Update XBoard docs

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@c %**start of header
@setfilename xboard.info
@settitle XBoard
@c %**end of header

@include version.texi

@ifinfo
@format
INFO-DIR-SECTION Games
START-INFO-DIR-ENTRY
* xboard: (xboard).         An X Window System graphical chessboard.
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@end ifinfo

@titlepage
@title XBoard

@page
@vskip 0pt plus 1filll
@include copyright.texi

@end titlepage
@ifset man
.TH xboard 6 "$Date: " "GNU"
.SH NAME
.PP
xboard @- X graphical user interface for chess
.SH SYNOPSIS
.PP
.B xboard [options]
.br
.B xboard -ics -icshost hostname [options]
.br
.B xboard -ncp [options]
.br
.B |pxboard
.br
.B cmail [options]
@end ifset

@node Top
@top Introduction
@cindex introduction

@ifset man
.SH DESCRIPTION
@end ifset

XBoard is a graphical chessboard that can serve as a
user interface to chess engines (such as GNU Chess), the
Internet Chess Servers,
electronic mail correspondence chess, or your own collection of saved games.

This manual documents version @value{VERSION} of XBoard.

@menu
* Major modes::     The main things XBoard can do.
* Menus::           Menus, buttons, and keys.
* Options::         Command options supported by XBoard.
* Chess Servers::   Using XBoard with an Internet Chess Server (ICS).
* Firewalls::       Connecting to a chess server through a firewall.
* Environment::     Environment variables.
* Limitations::     Known limitations and/or bugs.
* Problems::        How and where to report any problems you run into.
* Contributors::    People who have helped developing XBoard.
* CMail::           Using XBoard for electronic correspondence chess.
* Other programs::  Other programs you can use with XBoard.
@ifnottex
* Copyright::       Copyright notice for this manual.
@end ifnottex
* Copying::         The GNU General Public License.

* Index::           Index of concepts and symbol names.
@end menu

@node Major modes
@chapter Major modes
@cindex Major modes

XBoard always runs in one of four major modes.  You select the
major mode from the command line when you start up XBoard.

@table @asis
@item xboard [options]
As an interface to GNU Chess or another chess engine running on your
machine, XBoard lets you play a game against the machine,
set up arbitrary positions, force variations, watch a game between two
chess engines, interactively analyze your stored games or set up and
analyze arbitrary positions.  (Note: Not all chess engines support
analysis.)
@item xboard -ics -icshost hostname [options]
As Internet Chess Server (ICS) interface, XBoard
lets you play against other ICS users, observe games
they are playing, or review games that have recently finished.  Most
of the ICS "wild" chess variants are supported, including bughouse.
@item xboard -ncp [options]
XBoard can also be used simply
as an electronic chessboard to play through games. It will read and
write game files and allow you to play through variations
manually. You can use it to browse games off the net or review games
you have saved.  These features are also available in the other modes.
@item |pxboard
If you want to pipe games into XBoard, use the supplied shell
script @file{pxboard}.  For example, from the news reader @file{xrn},
find a message with one or more games in it, click the Save button,
and type @samp{|pxboard} as the file name.
@item cmail [options]
As an interface to electronic mail correspondence chess, XBoard
works with the cmail program. See @ref{CMail} below for
instructions.
@end table

@node Menus
@chapter Menus, buttons, and keys
@cindex Menus

To move a piece, you can drag it with the left mouse button, or you
can click the left mouse button once on the piece, then once more on
the destination square.  To drop a new piece on a square (when
applicable), press the middle or the right mouse button over the
square and select from the pop-up menu.  In cases where you can drop
either a white or black piece, use the middle button (or shift+right)
for white and the right button (or shift+middle) for black.  When you
are playing a bughouse game on an Internet Chess Server, a list of the
off-board pieces that each player has available is shown in the window
title after the player's name; in addition, the piece menus show the
number of pieces available of each type. From version 4.3.14 on, it is
also possible in crazyhouse, bughouse or shogi to drag and drop pieces
to the board from the holdings squares displayed next to the board.
This latter method for dropping pieces during a game is preferred,
and the piece-drop menu is now deprecated (except for editing a position).
Although the old behavior can still be selected through a command-line
option, the default function of the right mouse button is to display
the position the chess program thinks it will end up in,
while moving the mouse vertically with this button pressed will step
through the principal variation to show how this position will be 
reached.
Lines of play displayed in the engine-output window an similarly
be played out on the board, by right-clicking on them.

When connected to an ICS, it is possible to call up a graphical
representation of players seeking a game in stead of the chess board,
when the latter is not in use
(i.e. when you are not playing or observing).
Left-clicking the display area will switch between this 'seek graph'
and the chess board.
Hovering the mouse pointer over a dot will show the details of the
seek ad in the message field above the board.
Left-clicking the dot will challenge that player.
Right-clicking a dot will 'push it to the back',
to reveal any dots that were hidden behind it.
Right-clicking off dots will refresh the graph.

Most other XBoard commands are available from the menu bar. The most
frequently used commands also have shortcut keys or on-screen buttons.
Some rarely used parameters can only be set through options on the
command line used to invoke XBoard.

XBoard uses a settings file, in which it can remember any changes to
the settings that are made through menus or command-line options,
so they will still apply when you restart XBoard for another session.
The settings can be saved into this file automatically when XBoard exits,
or on explicit request of the user.
The default name for the settings file is /etc/xboard/xboard.conf,
but in a standard install this file is only used as a master settings
file that determines the system-wide default settings,
and defers reading and writing of user settings to a user-specific
file like ~/.xboardrc in the user's home directory.

When XBoard is iconized, its graphical icon is a white knight if
it is White's turn to move, a black knight if it is Black's turn.  See
Iconize in @ref{Keys} below if you have problems getting this
feature to work.

@menu
* File Menu::       Accessing external games and positions.
* Mode Menu::       Selecting XBoard's mode.
* Action Menu::     Talking to the chess engine or ICS opponents.
* Step Menu::       Controlling the game.
* Options Menu::    User preferences.
* Help Menu::       Getting help.
* Keys::            Other shortcut keys.
@end menu

@node File Menu
@section File Menu
@cindex File Menu
@cindex Menu, File
@table @asis
@item New Game
@cindex New Game, Menu Item
Resets XBoard and the chess engine to the beginning of a new chess
game. The @kbd{r} key is a keyboard equivalent. In Internet Chess
Server mode, clears the current state of XBoard, then
resynchronizes with the ICS by sending a refresh command. If you want to
stop playing, observing, or examining an ICS game, use an
appropriate command from the Action menu, not @samp{New Game}.
@xref{Action Menu}.
@item New Shuffle Game
@cindex New Shuffle Game, Menu Item
Similar to @samp{New Game}, but allows you to specify a particular initial position 
(according to a standardized numbering system)
in chess variants which use randomized opening positions (e.g. Chess960).
The selected opening position will persistently be chosen on any following
New Game command until you use this menu to select another. Selecting
position number -1 will produce a newly randomized position on any new game.
Using this menu item in variants that normally do not shuffle their opening position
does cause these variants to become shuffle variants until you use the
@samp{New Shuffle Game} menu to explicitly switch the randomization off,
or select a new variant.
@item New Variant
@cindex New variant, Menu Item
Allows you to select a new chess variant in non-ICS mode. 
(In ICS play, the ICS is responsible for deciding which variant will be played,
and XBoard adapts automatically.) If you play with an engine, the engine must
be able to play the selected variant, or the command will be ignored.
XBoard supports all major variants, such as xiangqi, shogi, chess, chess960,
Capablanca Chess, shatranj, crazyhouse, bughouse.
(But not every board size has built-in bitmaps for un-orthodox pieces!)
@item Load Game
@cindex Load Game, Menu Item
Plays a game from a record file. The @kbd{g} key is a keyboard equivalent.
A pop-up dialog prompts you for the file name. If the file contains more
than one game, a second pop-up dialog
displays a list of games (with information drawn from their PGN tags, if
any), and you can select the one you want. Alternatively, you can load the
Nth game in the file directly, by typing the number @kbd{N} after the
file name, separated by a space.

The game file parser will accept PGN (portable game notation),
or in fact almost any file that contains moves in algebraic
notation. 
Notation of the form @samp{P@@f7}
is accepted for piece-drops in bughouse games;
this is a nonstandard extension to PGN.
If the file includes a PGN position (FEN tag), or an old-style
XBoard position diagram bracketed by @samp{[--} and @samp{--]}
before the first move, the game starts from that position. Text
enclosed in parentheses, square brackets, or curly braces is assumed to
be commentary and is displayed in a pop-up window. Any other
text in the file is ignored. PGN variations (enclosed in
parentheses) also are treated as comments;
however, if you rights-click them in the comment window,
XBoard will shelve the current line, and load the the selected variation,
so you can step through it.
You can later revert to the previous line with the @samp{Revert} command.
This way you can walk quite complex varation trees with XBoard.
(The XBoard PGN parser is currenty limited to three nested levels of variations
on top of the main game, however.)
The nonstandard PGN tag [Variant "varname"] functions similarly to
the -variant command-line option (see below), allowing games in certain chess
variants to be loaded.  
Note that it must appear before any FEN tag for XBoard to recognize
variant FENs appropriately.
There is also a heuristic to 
recognize chess variants from the Event tag, by looking for the strings
that the Internet Chess Servers put there when saving variant ("wild") games.
@item Load Next Game
@cindex Load Next Game, Menu Item
Loads the next game from the last game record file you loaded.
The shifted @kbd{N} key is a keyboard equivalent.
@item Load Previous Game
@cindex Load Previous Game, Menu Item
Loads the previous game from the last game record file you
loaded.  The shifted @kbd{P} key is a keyboard equivalent.
Not available if the last game was loaded from a pipe.
@item Reload Same Game
@cindex Reload Same Game, Menu Item
Reloads the last game you loaded.
Not available if the last game was loaded from a pipe.
@item Save Game
@cindex Save Game, Menu Item
Appends a record of the current game to a file.
A pop-up dialog
prompts you for the file name. If the game did not begin with
the standard starting position, the game file includes the
starting position used. Games are saved in the PGN (portable
game notation) format, unless the oldSaveStyle option is true,
in which case they are saved in an older format that is specific
to XBoard. Both formats are human-readable, and both can be
read back by the @samp{Load Game} command.
Notation of the form @samp{P@@f7}
is accepted for piece-drops in bughouse games;
this is a nonstandard extension to PGN.
@item Copy Game
@cindex Copy Game, Menu Item
Copies a record of the current game to an internal clipboard in PGN
format and sets the X selection to the game text.  The game can be
pasted to another application (such as a text editor or another copy
of XBoard) using that application's paste command.  In many X
applications, such as xterm and emacs, the middle mouse button can be
used for pasting; in XBoard, you must use the Paste Game command.
@item Paste Game
@cindex Paste Game, Menu Item
Interprets the current X selection as a game record and loads it, as
with Load Game.
@item Load Position
@cindex Load Position, Menu Item
Sets up a position from a position file.  A pop-up dialog prompts
you for the file name. If the file contains more than one saved
position, and you want to load the Nth one, type the number N
after the file name, separated by a space. Position files must
be in FEN (Forsythe-Edwards notation), or in the format that the
Save Position command writes when oldSaveStyle is turned on.
@item Load Next Position
@cindex Load Next Position, Menu Item
Loads the next position from the last position file you loaded.
@item Load Previous Position
@cindex Load Previous Position, Menu Item
Loads the previous position from the last position file you
loaded.  Not available if the last position was loaded from a pipe.
@item Reload Same Position
@cindex Reload Same Position, Menu Item
Reloads the last position you loaded.
Not available if the last position was loaded from a pipe.
@item Save Position
@cindex Save Game, Menu Item
Appends a diagram of the current position to a file.
A pop-up dialog
prompts you for the file name. Positions are saved in
FEN (Forsythe-Edwards notation) format unless the @code{oldSaveStyle}
option is true, in which case they are saved in an older,
human-readable format that is specific to XBoard. Both formats
can be read back by the @samp{Load Position} command.
@item Copy Position
@cindex Copy Position, Menu Item
Copies the current position to an internal clipboard in FEN format and
sets the X selection to the position text.  The position can be pasted
to another application (such as a text editor or another copy of
XBoard) using that application's paste command.  In many X
applications, such as xterm and emacs, the middle mouse button can be
used for pasting; in XBoard, you must use the Paste Position command.
@item Paste Position
@cindex Paste Position, Menu Item
Interprets the current X selection as a FEN position and loads it, as
with Load Position.
@item Mail Move
@itemx Reload CMail Message
@cindex Mail Move, Menu Item
@cindex Reload CMail Message, Menu Item
See @ref{CMail}.
@item Exit
@cindex Exit, Menu Item
Exits from XBoard. The shifted @kbd{Q} key is a keyboard equivalent.
@end table

@node Mode Menu
@section Mode Menu
@cindex Menu, Mode
@cindex Mode Menu
@table @asis
@item Machine White
@cindex Machine White, Menu Item
Tells the chess engine to play White.
@item Machine Black
@cindex Machine Black, Menu Item
Tells the chess engine to play Black.
@item Two Machines
@cindex Two Machines, Menu Item
Plays a game between two chess engines.
@item Analysis Mode
@cindex Analysis Mode, Menu Item
XBoard tells the chess engine to start analyzing the current game/position
and shows you the analysis as you move pieces around.
Note: Some chess engines do not support Analysis mode.

To set up a position to analyze, you do the following:

1. Select Edit Position from the Mode Menu

2. Set up the position.  Use the middle and right buttons to
bring up the white and black piece menus.

3. When you are finished, click on either the Black or White
clock to tell XBoard which side moves first.

4. Select Analysis Mode from the Mode Menu to start the analysis.

The analysis function can also be used when observing games on an ICS
with an engine loaded (zippy mode); the engine then will analyse
the positions as they occur in the observed game.
@item Analyze File
@cindex Analyze File, Menu Item
This option lets you load a game from a file (PGN, XBoard format, etc.)
and analyze it. When you select this menu item, a pop-up window appears
and asks for a file name to load.
If the file contains multiple games, another pop up appears that lets
you select which game you wish to analyze.
After a game is loaded, use the XBoard arrow buttons to step
forwards/backwards through the game and watch the analysis.
Note: Some chess engines do not support Analysis mode.
@item ICS Client
@cindex ICS Client, Menu Item
This is the normal mode when XBoard
is connected to a chess server.  If you have moved into
Edit Game or Edit Position mode, you can select this option to get out.

To use xboard in ICS mode, run it in the foreground with the -ics
option, and use the terminal you started it from to type commands and
receive text responses from the chess server.  See
@ref{Chess Servers} below for more information.

XBoard activates some special position/game editing features when you
use the @kbd{examine} or @kbd{bsetup} commands on ICS and you have
@samp{ICS Client} selected on the Mode menu.  First, you can issue the
ICS position-editing commands with the mouse.  Move pieces by dragging
with mouse button 1.  To drop a new piece on a square, press mouse
button 2 or 3 over the square.  This brings up a menu of white pieces
(button 2) or black pieces (button 3).  Additional menu choices let
you empty the square or clear the board.  Click on the White or Black
clock to set the side to play.  You cannot set the side to play or
drag pieces to arbitrary squares while examining on ICC, but you can
do so in @kbd{bsetup} mode on FICS.  In addition, the menu commands
@samp{Forward}, @samp{Backward}, @samp{Pause}, and @samp{Stop Examining}
have special functions in this mode; see below.
@item Edit Game
@cindex Edit Game, Menu Item
Allows you to make moves for both Black and White, and to change
moves after backing up with the @samp{Backward} command. The clocks do
not run.

In chess engine mode, the chess engine continues to check moves for legality
but does not participate in the game. You can bring the chess engine
into the game by selecting @samp{Machine White}, @samp{Machine Black},
or @samp{Two Machines}.

In ICS mode, the moves are not sent to the ICS: @samp{Edit Game} takes
XBoard out of ICS Client mode and lets you edit games locally.
If you want to edit games on ICS in a way that other ICS users
can see, use the ICS @kbd{examine} command or start an ICS match
against yourself.
@item Edit Position
@cindex Edit Position, Menu Item
Lets you set up an arbitrary board position.
Use mouse button 1 to drag pieces to new squares, or to delete a piece
by dragging it off the board or dragging an empty square on top of it.
To drop a new piece on a square, press mouse button 2 or 3 over the
square. This brings up a menu of white pieces (button 2) or
black pieces (button 3). Additional menu choices let you empty the
square or clear the board. You can set the side to play next by
clicking on the word White or Black at the top of the screen.
Selecting @samp{Edit Position} causes XBoard to discard
all remembered moves in the current game.

In ICS mode, changes made to the position by @samp{Edit Position} are
not sent to the ICS: @samp{Edit Position} takes XBoard out of
@samp{ICS Client} mode and lets you edit positions locally. If you want to
edit positions on ICS in a way that other ICS users can see, use
the ICS @kbd{examine} command, or start an ICS match against yourself.
(See also the ICS Client topic above.)
@item Training
@cindex Training, Menu Item
Training mode lets you interactively guess the moves of a game for one
of the players. You guess the next move of the game by playing the
move on the board. If the move played matches the next move of the
game, the move is accepted and the opponent's response is auto-played.
If the move played is incorrect, an error message is displayed.  You
can select this mode only while loading a game (that is, after
selecting @samp{Load Game} from the File menu).  While XBoard is in 
@samp{Training} mode, the navigation buttons are disabled.
@item Show Engine Output
@cindex Show Engine Output, Menu Item
Shows or hides a window in which the thinking output of any loaded engines
is displayed.
XBoard will display lines of thinking output of the same depth ordered by score, 
(highest score on top), rather than in the order the engine produced them. 
Usually this amounts to the same, as a normal engine search will only find new PV 
(and emit it as thinking output) 
when it searches a move with a higher score than the previous variation. 
But when the engine is in multi-variation mode this needs not always be true, 
and it is more convenient for someone analyzing games to see the moves sorted by score. 
The order in which the engine found them is only of interest to the engine author, 
and can still be deduced from the time or node count printed with the line.
@item Show Evaluation Graph
@cindex Show Evaluation Graph, Menu Item
Shows or hides a window which displays a graph of how the engine score(s)
evolved as a function of the move number. Clicking on the graph will bring
the corresponding position in the board display.
@item Show Game List
@cindex Show Game List, Menu Item
Shows or hides the list of games generated by the last @samp{Load Game}
command.
@item Show Move History
@cindex Show Move History, Menu Item
Shows or hides a list of moves of the current game.
This list allows you to move the display to any earlier position in the game
by clicking on the corresponding move.
@item Edit Tags
@cindex Edit Tags, Menu Item
Lets you edit the PGN (portable game notation)
tags for the current game. After editing, the tags must still conform to
the PGN tag syntax:

@example
<tag-section> ::= <tag-pair> <tag-section>
                        <empty>
<tag-pair> ::= [ <tag-name> <tag-value> ]
<tag-name> ::= <identifier>
<tag-value> ::= <string>
@end example
@noindent
See the PGN Standard for full details. Here is an example:

@example
[Event "Portoroz Interzonal"]
[Site "Portoroz, Yugoslavia"]
[Date "1958.08.16"]
[Round "8"]
[White "Robert J. Fischer"]
[Black "Bent Larsen"]
[Result "1-0"]
@end example
@noindent
Any characters that do not match this syntax are silently ignored. Note that
the PGN standard requires all games to have at least the seven tags shown
above. Any that you omit will be filled in by XBoard
with @samp{?} (unknown value), or @samp{-} (inapplicable value).
@item Edit Comment
@cindex Edit Comment, Menu Item
Adds or modifies a comment on the current position. Comments are
saved by @samp{Save Game} and are displayed by @samp{Load Game},
@samp{Forward}, and @samp{Backward}.
@item ICS Input Box
@cindex ICS Input Box, Menu Item
If this option is set in ICS mode,
XBoard
creates an extra window that you can use for typing in ICS commands.
The input box is especially useful if you want to type in something long or do
some editing on your input, because output from ICS doesn't get mixed
in with your typing as it would in the main terminal window.
@item Pause
@cindex Pause, Menu Item
Pauses updates to the board, and if you are playing against a chess engine,
also pauses your clock. To continue, select @samp{Pause} again, and the
display will automatically update to the latest position.
The @samp{P} button and keyboard @kbd{p} key are equivalents.

If you select Pause when you are playing against a chess engine and
it is not your move, the chess engine's clock
will continue to run and it will eventually make a move, at which point
both clocks will stop. Since board updates are paused, however,
you will not see the move until you exit from Pause mode (or select Forward).
This behavior is meant to simulate adjournment with a sealed move.

If you select Pause while you are observing or examining a game on a
chess server, you can step backward and forward in the current history
of the examined game without affecting the other observers and
examiners, and without having your display jump forward to the latest
position each time a move is made. Select Pause again to reconnect
yourself to the current state of the game on ICS.

If you select @samp{Pause} while you are loading a game, the game stops
loading. You can load more moves manually by selecting @samp{Forward}, or
resume automatic loading by selecting @samp{Pause} again.
@end table

@node Action Menu
@section Action Menu
@cindex Menu, Action
@cindex Action, Menu
@table @asis
@item Accept
@cindex Accept, Menu Item
Accepts a pending match offer. If there is more than one offer
pending, you will have to type in a more specific command
instead of using this menu choice.
@item Decline
@cindex Decline, Menu Item
Declines a pending offer (match, draw, adjourn, etc.). If there
is more than one offer pending, you will have to type in a more
specific command instead of using this menu choice.
@item Call Flag
@cindex Call Flag, Menu Item
Calls your opponent's flag, claiming a win on time, or claiming
a draw if you are both out of time. You can also call your
opponent's flag by clicking on his clock or by pressing the
keyboard @kbd{t} key.
@item Draw
@cindex Draw, Menu Item
Offers a draw to your opponent, accepts a pending draw offer
from your opponent, or claims a draw by repetition or the 50-move
rule, as appropriate. The @kbd{d} key is a keyboard equivalent.
@item Adjourn
@cindex Adjourn, Menu Item
Asks your opponent to agree to adjourning the current game, or
agrees to a pending adjournment offer from your opponent.
@item Abort
@cindex Abort, Menu Item
Asks your opponent to agree to aborting the current game, or
agrees to a pending abort offer from your opponent. An aborted
game ends immediately without affecting either player's rating.
@item Resign
@cindex Resign, Menu Item
Resigns the game to your opponent. The shifted @kbd{R} key is a
keyboard equivalent.
@item Stop Observing
@cindex Stop Observing, Menu Item
Ends your participation in observing a game, by issuing the ICS
observe command with no arguments. ICS mode only.
@item Stop Examining
@cindex Stop Examining, Menu Item
Ends your participation in examining a game, by issuing the ICS
unexamine command. ICS mode only.
@item Upload to Examine
@cindex Upload to Examine, Menu Item
Create an examined game of the proper variant on the ICS,
and send the game there that is currenty loaded in XBoard
(e.g. through pasting or loading from file).
You must be connected to an ICS for this to work.
@item Adjudicate to White
@itemx Adjudicate to Black
@itemx Adjudicate Draw
@cindex Adjudicate to White, Menu Item
@cindex Adjudicate to Black, Menu Item
@cindex Adjudicate Draw, Menu Item
Terminate an ongoing game in Two-Machines mode (including match mode),
with as result a win for white, for black, or a draw, respectively.
The PGN file of the game will accompany the result string
by the comment "user adjudication".
@end table

@node Step Menu
@section Step Menu
@cindex Step Menu
@cindex Menu, Step
@table @asis
@item Backward
@cindex Backward, Menu Item
@cindex <, Button
Steps backward through a series of remembered moves.
The @samp{[<]} button and the @kbd{b} key are equivalents,
as is turning the mouse wheel towards you.
In addition, pressing the Control key steps back one move, and releasing
it steps forward again.

In most modes, @samp{Backward} only lets you look back at old positions;
it does not retract moves. This is the case if you are playing against
a chess engine, playing or observing a game on an ICS, or loading a game.
If you select @samp{Backward} in any of these situations, you will not
be allowed to make a different move. Use @samp{Retract Move} or
@samp{Edit Game} if you want to change past moves.

If you are examining an ICS game, the behavior of @samp{Backward}
depends on whether XBoard is in Pause mode. If Pause mode is
off, @samp{Backward} issues the ICS backward command, which backs up
everyone's view of the game and allows you to make a different
move. If Pause mode is on, @samp{Backward} only backs up your local
view.
@item Forward
@cindex Forward, Menu Item
@cindex >, Button
Steps forward through a series of remembered moves (undoing the
effect of @samp{Backward}) or forward through a game file. The
@samp{[>]} button and the @kbd{f} key are equivalents,
as is turning the mouse wheel away from you.

If you are examining an ICS game, the behavior of Forward
depends on whether XBoard is in Pause mode. If Pause mode is
off, @samp{Forward} issues the ICS forward command, which moves
everyone's view of the game forward along the current line. If
Pause mode is on, @samp{Forward} only moves your local view forward,
and it will not go past the position that the game was in when
you paused.
@item Back to Start
@cindex Back to Start, Menu Item
@cindex <<, Button
Jumps backward to the first remembered position in the game.
The @samp{[<<]} button and the shifted @kbd{B} key are equivalents.

In most modes, Back to Start only lets you look back at old
positions; it does not retract moves. This is the case if you
are playing against a local chess engine, playing or observing a game on
a chess server, or loading a game. If you select @samp{Back to Start} in any
of these situations, you will not be allowed to make different
moves. Use @samp{Retract Move} or @samp{Edit Game} if you want to change past
moves; or use Reset to start a new game.

If you are examining an ICS game, the behavior of @samp{Back to
Start} depends on whether XBoard is in Pause mode. If Pause mode
is off, @samp{Back to Start} issues the ICS @samp{backward 999999}
command, which backs up everyone's view of the game to the start and
allows you to make different moves. If Pause mode is on, @samp{Back
to Start} only backs up your local view.
@item Forward to End
@cindex Forward to End, Menu Item
@cindex >>, Button
Jumps forward to the last remembered position in the game. The
@samp{[>>]} button and the shifted @kbd{F} key are equivalents.

If you are examining an ICS game, the behavior of @samp{Forward to
End} depends on whether XBoard is in Pause mode. If Pause mode
is off, @samp{Forward to End} issues the ICS @samp{forward 999999}
command, which moves everyone's view of the game forward to the end of
the current line. If Pause mode is on, @samp{Forward to End} only moves
your local view forward, and it will not go past the position
that the game was in when you paused.
@item Revert
@itemx Annotate
@cindex Revert, Menu Item
@cindex Annotate, Menu Item
If you are examining an ICS game and Pause mode is off, issues
the ICS command @samp{revert}.
In local mode, when you were editing or analyzing a game, 
and have been entering a number of moves by hand, starting from 
a position not at the end of the game, 
the revert command restores the game to the variation you started from. 
This can be applied recursively, 
so that you can analyze variations on variations; 
each time you create a new variation by entering an alternative move, 
the current variation will be shelved. 
Revert allows you to return to the most recently shelved variation.
The difference between Revert and Annotate is that with the latter,
the variation you had been entering and are now abandoning
is currently added as a comment 
(in PGN variation syntax, i.e. between parentheses)
to the original move where you deviated.
Note that such 'variation comments' can be played out on the board again
(also when they were loaded from file)
by clicking them in the comment window.
@item Truncate Game
@cindex Truncate Game, Menu Item
Discards all remembered moves of the game beyond the current
position. Puts XBoard into @samp{Edit Game} mode if it was not there
already.
@item Move Now
@cindex Move Now, Menu Item
Forces the chess engine to move immediately. Chess engine mode only.
@item Retract Move
@cindex Retract Move, Menu Item
Retracts your last move. In chess engine mode, you can do this only
after the chess engine has replied to your move; if the chess engine is still
thinking, use @samp{Move Now} first. In ICS mode, @samp{Retract Move}
issues the command @samp{takeback 1} or @samp{takeback 2}
depending on whether it is your opponent's move or yours.
@end table

@node Options Menu
@section Options Menu
@cindex Menu, Options
@cindex Options Menu
@table @asis
@item Flip View
@cindex Flip View, Menu Item
Inverts your view of the chess board for the duration of the
current game. Starting a new game returns the board to normal.
The @kbd{v} key is a keyboard equivalent.
@item Adjudications
@cindex Adjudications, Menu Item
Pops up a sub-menu where you can enable or disable various adjudications
that XBoard can perform in engine-engine games.
You can instruct XBoard to detect and terminate the game on checkmate
or stalemate, even if the engines would not do so, to verify engine
result claims (forfeiting engines that make false claims), rather than
naively following the engine, to declare draw on positions
which can never be won for lack of mating material, (e.g. KBK),
or which are impossible to win unless the opponent seeks its own demise 
(e.g. KBKN).
For these adjudications to work, @samp{Test Legality} should be switched on.
It is also possible to instruct XBoard to enforce a 50-move or 3-fold-repeat
rule and automatically declare draw (after a user-adjustable number of moves
or repeats) even if the engines are prepared to go on.
It is also possible to have XBoard declare draw on games that seem to drag on 
forever, or adjudicate a loss if both engines agree (for 3 consecutive moves) that one
of them is behind more than a user-adjustable score threshold.
For the latter adjudication to work, XBoard should be able to properly understand
the engine's scores. To facilitate the latter, you can inform xboard here if
the engines report scores from the viewpoint of white, or from that of their own color.
@item General Settings
@cindex General Settings, Menu Item
Pops up a sub-menu where you can set some engine parameters common to most engines,
such as hash-table size, tablebase cache size, maximum number of processors
that SMP engines can use, and where to find the Polyglot adapter needed
to run UCI engines under XBoard. The feature that allows setting of these parameters on
engines is new since XBoard 4.3.15, so not many XBoard/WinBoard engines respond
to it yet, but UCI engines should.
It is also possible to specify a GUI opening book here, i.e. an opening
book that XBoard consults for any position a playing engine gets in.
It then forces the engine to play the book move, rather than to think up its own,
if that position is found in the book.
The book can switched on and off independently for either engine.
@item Engine #N Settings
@cindex Engine Settings, Menu Item
@cindex Engine #1 Settings, Menu Item
@cindex Engine #2 Settings, Menu Item
Pop up a menu dialog to alter the settings specific to the applicable engine.
(The second engine is only accessible once it has been used in Two-Machines mode.)
For each parameter the engine allows to be set,
a control element will appear in this dialog that can be used to alter the value.
Depending on the type of parameter (text string, number, multiple choice,
on/off switch, instantaneous signal) the appropriate control will appear,
with a description next to it.
XBoard has no idea what these values mean; it just passes them on to the engine.
How this dialog looks is completely determined by the engine,
and XBoard just passes it on to the user.
Many engines do not have any parameters that can be set by the user,
and in that case the dialog will be empty (except for the OK and cancel buttons).
UCI engines usually have many parameters. (But these are only visible with
a sufficiently modern version of the Polyglot adapter needed to run UCI engines,
e.g. Polyglot 1.4.55b.) For native XBoard engines this is less common.
@item Time Control
@cindex Time Control, Menu Item
Pops up a sub-menu where you can set the time-control parameters interactively.
Allows you to select classical or incremental time controls,
set the moves per session, session duration, and time increment.
Also allows specification of time-odds factors for one or both engines.
If an engine is given a time-odds factor N, all time quota it gets, 
be it at the beginning of a session or through the time increment or
fixed time per move, will be divided by N.
@item Always Queen
@cindex Always Queen, Menu Item
If this option is off, XBoard brings up a dialog
box whenever you move a pawn to the last rank, asking what piece
you want to promote it to. If the option is true, your pawns are
always promoted to queens. Your opponent can still under-promote.
@item Animate Dragging
@cindex Animate Dragging, Menu Item
If Animate Dragging is on, while you are dragging a piece with the
mouse, an image of the piece follows the mouse cursor.
If Animate Dragging is off, there is no visual feedback while you are
dragging a piece, but if Animate Moving is on, the move will be
animated when it is complete. 
@item Animate Moving
@cindex Animate Moving, Menu Item
If Animate Moving is on, all piece moves are animated.  An image of the
piece is shown moving from the old square to the new square when the
move is completed (unless the move was already animated by Animate Dragging).
If Animate Moving is off, a moved piece instantly disappears from its
old square and reappears on its new square when the move is complete.
@item Auto Comment
@cindex Auto Comment, Menu Item
If this option is on, any remarks made on ICS while you are observing or
playing a game are recorded as a comment on the current move.  This includes
remarks made with the ICS commands @kbd{say}, @kbd{tell}, @kbd{whisper},
and @kbd{kibitz}.
Limitation: remarks that you type yourself are not recognized;
XBoard scans only the output from ICS, not the input you type to it.
@item Auto Flag
@cindex Auto Flag, Menu Item
If this option is on and one player runs out of time
before the other,
XBoard
will automatically call his flag, claiming a win on time.
In ICS mode, Auto Flag will only call your opponent's flag, not yours,
and the ICS may award you a draw instead of a win if you have
insufficient mating material.  In local chess engine mode,
XBoard
may call either player's flag and will not take material into account.
@item Auto Flip View
@cindex Auto Flip View, Menu Item
If the Auto Flip View option is on when you start a game, the board
will be automatically oriented so that your pawns move from the bottom
of the window towards the top.
@item Auto Observe
@cindex Auto Observe, Menu Item
If this option is on and you add a player to your @code{gnotify}
list on ICS, XBoard will automatically observe all of that
player's games, unless you are doing something else (such as
observing or playing a game of your own) when one starts.
The games are displayed 
from the point of view of the player on your gnotify list; that is, his
pawns move from the bottom of the window towards the top.
Exceptions:  If both players in a game are on your gnotify list, if
your ICS 
@code{highlight}
variable is set to 0, or if the ICS you are using does not 
properly support observing from Black's point of view,
you will see the game from White's point of view.
@item Auto Raise Board
@cindex Auto Raise Board, Menu Item
If this option is on, whenever a new game begins, the chessboard window
is deiconized (if necessary) and raised to the top of the stack of windows.
@item Auto Save
@cindex Auto Save, Menu Item
If this option is true, at the end of every game XBoard prompts
you for a file name and appends a record of the game to the file
you specify. 
Disabled if the @code{saveGameFile} command-line
option is set, as in that case all games are saved to the specified file.
@xref{Load and Save options}.
@item Blindfold
@cindex Blindfold, Menu Item
If this option is on, XBoard displays the board as usual but does
not display pieces or move highlights.  You can still move in the
usual way (with the mouse or by typing moves in ICS mode), even though
the pieces are invisible.
@item Flash Moves
@cindex Flash Moves, Menu Item
If this option is on, whenever a move is completed, the moved piece flashes.
The number of times to flash is set by the flashCount command-line
option; it defaults to 3 if Flash Moves is first turned on from the menu.

If you are playing a game on an ICS, the board is always
oriented at the start of the game so that your pawns move from
the bottom of the window towards the top. Otherwise, the starting
orientation is determined by the @code{flipView} command line option;
if it is false (the default), White's pawns move from bottom to top
at the start of each game; if it is true, Black's pawns move from
bottom to top. @xref{User interface options}.
@item Get Move List
@cindex Get Move List, Menu Item
If this option is on, whenever XBoard
receives the first board of a new ICS game (or a different game from
the one it is currently displaying), it
retrieves the list of past moves from the ICS.
You can then review the moves with the @samp{Forward} and @samp{Backward}
commands
or save them with @samp{Save Game}.  You might want to
turn off this option if you are observing several blitz games at once,
to keep from wasting time and network bandwidth fetching the move lists over
and over.
When you turn this option on from the menu, XBoard
immediately fetches the move list of the current game (if any).
@item Highlight Dragging
@cindex Highlight Dragging, Menu Item
If Highlight Dragging is on, and the option -showTargetSquares is also on
in the settings file, all squares a piece that is 'picked up' with the mouse
can legally move to are highighted with a fat colored dot in the
highlightColor (non-captures) or premoveHighlightColor (captures).
Legality testing must be on for XBoard to know how the piece moves.
@item Highlight Last Move
@cindex Highlight Last Move, Menu Item
If Highlight Last Move is on, after a move is made, the starting and
ending squares remain highlighted. In addition, after you use Backward
or Back to Start, the starting and ending squares of the last move to
be unmade are highlighted.
@item Move Sound
@cindex Move Sound, Menu Item
If this option is on, XBoard alerts you by playing a sound
after each of your opponent's moves (or after every
move if you are observing a game on the Internet Chess Server).
The sound is not played after moves you make or moves read from a
saved game file. By default, the
sound is the terminal bell, but on some systems you can change it
to a sound file using the soundMove option; see below.

If you turn on this option when using XBoard with the Internet
Chess Server, you will probably want to give the
@kbd{set bell 0}
command to the ICS, since otherwise the ICS will ring the terminal bell
after every move (not just yours). (The @file{.icsrc} file
is a good place for this; see @ref{ICS options}.)
@item ICS Alarm
@cindex ICS Alarm, Menu Item
When this option is on, an alarm sound is played when your clock
counts down to the icsAlarmTime (by default, 5 seconds) in an ICS
game.  For games with time controls that include an increment, the
alarm will sound each time the clock counts down to the icsAlarmTime.
By default, the alarm sound is the terminal bell, but on some systems
you can change it to a sound file using the soundIcsAlarm option; see
below.
@item Old Save Style
@cindex Old Save Style, Menu Item
If this option is off, XBoard saves games in PGN
(portable game notation) and positions in FEN (Forsythe-Edwards
notation).  If the option is on, a save style that is compatible
with older versions of XBoard is used instead.
The old position style is more human-readable
than FEN; the old game style has no particular advantages.
@item Periodic Updates
@cindex Periodic Updates, Menu Item
If this option is off (or if
you are using a chess engine that does not support periodic updates),
the analysis window
will only be updated when the analysis changes. If this option is
on, the Analysis Window will be updated every two seconds.
@item Ponder Next Move
@cindex Ponder Next Move, Menu Item
If this option is off, the chess engine will think only when it is on
move.  If the option is on, the engine will also think while waiting
for you to make your move.
@item Popup Exit Message
@cindex Popup Exit Message, Menu Item
If this option is on, when XBoard wants to display a message just
before exiting, it brings up a modal dialog box and waits for you to
click OK before exiting.  If the option is off, XBoard prints the
message to standard error (the terminal) and exits immediately.
@item Popup Move Errors
@cindex Popup Move Errors, Menu Item
If this option is off, when you make an error in moving (such as
attempting an illegal move or moving the wrong color piece), the
error message is displayed in the message area.  If the option is
on, move errors are displayed in small pop-up windows like other errors.
You can dismiss an error pop-up either by clicking its OK button or by
clicking anywhere on the board, including down-clicking to start a move.
@item Premove
@cindex Premove, Menu Item
If this option is on while playing a game on an ICS, you can register
your next planned move before it is your turn.  Move the piece with
the mouse in the ordinary way, and the starting and ending squares
will be highlighted with a special color (red by default).  When it is
your turn, if your registered move is legal, XBoard will send it to
ICS immediately; if not, it will be ignored and you can make a
different move.  If you change your mind about your premove, either
make a different move, or double-click on any piece to cancel the move
entirely.
@item Quiet Play
@cindex Quiet Play, Menu Item
If this option is on, XBoard will automatically issue an ICS
@kbd{set shout 0}
command whenever you start a game and a
@kbd{set shout 1}
command whenever you finish one.  Thus, you will not be distracted
by shouts from other ICS users while playing.
@item Show Coords
@cindex Show Coords, Menu Item
If this option is on, XBoard displays algebraic coordinates
along the board's left and bottom edges.
@item Hide Thinking
@cindex Hide Thinking, Menu Item
If this option is off, the chess engine's notion of the score and best
line of play from the current position is displayed as it is
thinking. The score indicates how many pawns ahead (or if negative,
behind) the chess engine thinks it is. In matches between two
machines, the score is prefixed by @samp{W} or @samp{B} to indicate
whether it is showing White's thinking or Black's, and only the thinking
of the engine that is on move is shown.
@item Test Legality
@cindex Test Legality, Menu Item
If this option is on, XBoard tests whether the moves you try to make
with the mouse are legal and refuses to let you make an illegal move.
Moves loaded from a file with @samp{Load Game} are also checked.  If
the option is off, all moves are accepted, but if a local chess engine
or the ICS is active, they will still reject illegal moves.  Turning
off this option is useful if you are playing a chess variant with
rules that XBoard does not understand.  (Bughouse, suicide, and wild
variants where the king may castle after starting on the d file are
generally supported with Test Legality on.)
@item Save Settings Now
@cindex Save Settings Now, Menu Item
Selecting this menu item causes the current XBoard settings to be
written to the settings file, so they will also apply in future sessions.
Note that some settings are 'volatile', and are not saved,
because XBoard considers it too unlikely that you want those to apply
next time.
In particular this applies to the Chess program names, and all options
giving information on those Chess programs (such as their directory,
if they have their own opening book, if they are UCI or native XBoard),
or the variant you are playing.
Such options would still be understood when they appear in the settings
file in case they were put there with the aid of a text editor, but they
would disappear from the file as soon as you save the settings.
@item Save Settings on Exit
@cindex Save Settings on Exit, Menu Item
Setting this option has no immediate effect, but causes the settings
to be saved when you quit XBoard. What happens then is otherwise 
identical to what happens when you use select "Save Settings Now",
see there.
@end table

@node Help Menu
@section Help Menu
@cindex Menu, Help
@cindex Help Menu
@table @asis
@item Info XBoard
@cindex Info XBoard, Menu Item
Displays the XBoard documentation in info format.  For this feature to
work, you must have the GNU info program installed on your system, and
the file @file{xboard.info} must either be present in the current
working directory, or have been installed by the @samp{make install}
command when you built XBoard.
@item Man XBoard
@cindex Man XBoard, Menu Item
Displays the XBoard documentation in man page format.  For this
feature to work, the file @file{xboard.6} must have been installed by
the @samp{make install} command when you built XBoard, and the
directory it was placed in must be on the search path for your
system's @samp{man} command.
@item Hint
@cindex Hint, Menu Item
Displays a move hint from the chess engine.
@item Book
@cindex Book, Menu Item
Displays a list of possible moves from the chess engine's opening
book.  The exact format depends on what chess engine you are using.
With GNU Chess 4, the first column gives moves, the second column
gives one possible response for each move, and the third column shows
the number of lines in the book that include the move from the first
column. If you select this option and nothing happens, the chess
engine is out of its book or does not support this feature.
@item About XBoard
@cindex About XBoard, Menu Item
Shows the current XBoard version number.
@end table

@node Keys
@section Other Shortcut Keys
@cindex Keys
@cindex Shortcut keys
@table @asis
@item Iconize
Pressing the @kbd{i} or @kbd{c} key iconizes XBoard. The graphical
icon displays a white knight if it is White's move, or a black knight
if it is Black's move. If your X window manager displays only text
icons, not graphical ones, check its documentation; there is probably
a way to enable graphical icons.  If you get black and white reversed,
we would like to hear about it; see @ref{Problems} below for
instructions on how to report this problem.
@end table

You can add or remove shortcut keys using the X resources
@code{form.translations}. Here is an example of what would go in your
@file{.Xresources} file:

@example
XBoard*form.translations: \
  Shift<Key>?: AboutGameProc() \n\
  <Key>y: AcceptProc() \n\
  <Key>n: DeclineProc() \n\
  <Key>i: NothingProc()
@end example
@noindent
Binding a key to @code{NothingProc} makes it do nothing, thus removing
it as a shortcut key. The XBoard commands that can be bound to keys
are:

@example
AbortProc, AboutGameProc, AboutProc, AcceptProc, AdjournProc,
AlwaysQueenProc, AnalysisModeProc, AnalyzeFileProc,
AnimateDraggingProc, AnimateMovingProc, AutobsProc, AutoflagProc,
AutoflipProc, AutoraiseProc, AutosaveProc, BackwardProc,
BlindfoldProc, BookProc, CallFlagProc, CopyGameProc, CopyPositionProc,
DebugProc, DeclineProc, DrawProc, EditCommentProc, EditGameProc,
EditPositionProc, EditTagsProc, EnterKeyProc, FlashMovesProc,
FlipViewProc, ForwardProc, GetMoveListProc, HighlightLastMoveProc,
HintProc, Iconify, IcsAlarmProc, IcsClientProc, IcsInputBoxProc,
InfoProc, LoadGameProc, LoadNextGameProc, LoadNextPositionProc,
LoadPositionProc, LoadPrevGameProc, LoadPrevPositionProc,
LoadSelectedProc, MachineBlackProc, MachineWhiteProc, MailMoveProc,
ManProc, MoveNowProc, MoveSoundProc, NothingProc, OldSaveStyleProc,
PasteGameProc, PastePositionProc, PauseProc, PeriodicUpdatesProc,
PonderNextMoveProc, PopupExitMessageProc, PopupMoveErrorsProc,
PremoveProc, QuietPlayProc, QuitProc, ReloadCmailMsgProc,
ReloadGameProc, ReloadPositionProc, RematchProc, ResetProc,
ResignProc, RetractMoveProc, RevertProc, SaveGameProc,
SavePositionProc, ShowCoordsProc, ShowGameListProc, ShowThinkingProc,
StopExaminingProc, StopObservingProc, TestLegalityProc, ToEndProc,
ToStartProc, TrainingProc, TruncateGameProc, and TwoMachinesProc.
@end example

@node Options
@chapter Options
@cindex Options
@cindex Options

This section documents the command-line options to XBoard.  You can
set these options in two ways: by typing them on the shell command
line you use to start XBoard, or by setting them as X resources
(typically in your @file{.Xresources} file).  Many of the options
cannot be changed while XBoard is running; others set the initial
state of items that can be changed with the @ref{Options} menu.

Most of the options have both a long name and a short name. To turn a
boolean option on or off from the command line, either give its long
name followed by the value true or false
(@samp{-longOptionName true}), or give just the short name to turn the
option on (@samp{-opt}), or the short name preceded by @samp{x} to
turn the option off (@samp{-xopt}). For options that take strings or
numbers as values, you can use the long or short option names
interchangeably.

Each option corresponds to an X resource with the same name, so
if you like, you can set options in your @file{.Xresources} file
or in a file named @file{XBoard} in your home directory.
For options that have two names, the longer one is the name of
the corresponding X resource; the short name is not recognized.
To turn a boolean option on or off as an
X resource, give its long name followed by the value
true or false (@samp{XBoard*longOptionName: true}).

@menu
* Chess engine options::        Controlling the chess engine.
* UCI + WB Engine Settings::    Setting some very common engine parameters
* ICS options::                 Connecting to and using ICS.
* Load and Save options::       Input/output options.
* User interface options::      Look and feel options.
* Adjudication Options::        Control adjudication of engine-engine games.
* Other options::               Miscellaneous.
@end menu

@node Chess engine options
@section Chess Engine Options
@cindex options, Chess engine
@cindex Chess engine options
@table @asis
@item -tc or -timeControl minutes[:seconds]
@cindex tc, option
@cindex timeControl, option
Each player begins with his clock set to the @code{timeControl} period.
Default: 5 minutes.
The additional options @code{movesPerSession} and @code{timeIncrement}
are mutually exclusive.  
@item -mps or -movesPerSession moves
@cindex mps, option
@cindex movesPerSession, option
When both players have made @code{movesPerSession} moves, a
new @code{timeControl} period is added to both clocks.  Default: 40 moves.
@item -inc or -timeIncrement seconds
@cindex inc, option
@cindex timeIncrement, option
If this option is specified, @code{movesPerSession} is ignored.
Instead, after each player's move, @code{timeIncrement} seconds are
added to his clock.  
Use @samp{-inc 0} if you want to require the entire
game to be played in one @code{timeControl} period, with no increment.
Default: -1, which specifies @code{movesPerSession} mode.
@item -clock/-xclock or -clockMode true/false
@cindex clock, option
@cindex clockMode, option
Determines whether or not to display the chess clocks. If clockMode is
false, the clocks are not shown, but the side that is to play next
is still highlighted. Also, unless @code{searchTime}
is set, the chess engine still keeps track of the clock time and uses it to
determine how fast to make its moves.
@item -st or -searchTime minutes[:seconds]
@cindex st, option
@cindex searchTime, option
Tells the chess engine to spend at most the given amount of time
searching for each of its moves. Without this option, the chess engine
chooses its search time based on the number of moves and amount
of time remaining until the next time control.
Setting this option also sets clockMode to false.
@item -depth or -searchDepth number
@cindex sd, option
@cindex searchDepth, option
Tells the chess engine to look ahead at most the given number of moves
when searching for a move to make. Without this option, the chess
engine chooses its search depth based on the number of moves and
amount of time remaining until the next time control.  With the option,
the engine will cut off its search early if it reaches the specified depth.
@item -firstNPS number
@itemx -secondNPS number
@cindex firstNPS, option
@cindex secondNPS, option
Tells the chess engine to use an internal time standard based on its node count, 
rather then wall-clock time, to make its timing decisions. 
The time in virtual seconds should be obtained by dividing the node count 
through the given number, like the number was a rate in nodes per second. 
Xboard will manage the clocks in accordance with this, relying on the number 
of nodes reported by the engine in its thinking output. If the given number equals zero, 
it can obviously not be used to convert nodes to seconds, and the time reported 
by the engine is used to decrement the XBoard clock in stead. The engine is supposed to 
report in CPU time it uses, rather than wall-clock time, in this mode. This option 
can provide fairer conditions for engine-engine matches on heavily loaded machines, 
or with very fast games (where the wall clock is too inaccurate). 
@code{showThinking} must be on for this option to work. Default: -1 (off).
Not many engines might support this yet!
@item -firstTimeOdds factor
@itemx -secondTimeOdds factor
@cindex firstTimeOdds, option
@cindex secondTimeOdds, option
Reduces the time given to the mentioned engine by the given factor. 
If pondering is off, the effect is indistinguishable from what would happen 
if the engine was running on an n-times slower machine. Default: 1.
@item -timeOddsMode mode
@cindex timeOddsMode, option
This option determines how the case is handled where both engines have a time-odds handicap. 
If mode=1, the engine that gets the most time will always get the nominal time, 
as specified by the time-control options, and its opponent's time is renormalized accordingly. 
If mode=0, both play with reduced time. Default: 0.
@item -hideThinkingFromHuman true/false
Controls the Hide Thinking option. @xref{Options Menu}. Default: true.
(Replaces the Show-Thinking option of older xboard versions.)
@item -thinking/-xthinking or -showThinking true/false
@cindex thinking, option
@cindex showThinking, option
Forces the engine to send thinking output to xboard. 
Used to be the only way to control if thinking output was displayed 
in older xboard versions,
but as the thinking output in xboard 4.3 is also used for several other
purposes (adjudication, storing in PGN file) the display of it is now controlled
by the new option Hide Thinking. @xref{Options Menu}. Default: false.
(But if xboard needs the thinking output for some purpose,
it makes the engine send it despite the setting of this option.)
@item -ponder/-xponder or -ponderNextMove true/false
@cindex ponder, option
@cindex ponderNextMove, option
Sets the Ponder Next Move menu option. @xref{Options Menu}. Default: true.
@item -smpCores number
Specifies the maximum number of CPUs an SMP engine is allowed to use.
Only works for engines that support the XBoard/WinBoard-protocol cores feature.
@item -mg or -matchGames n
@cindex mg, option
@cindex matchGames, option
Automatically runs an n-game match between two chess engines,
with alternating colors.
If the @code{loadGameFile} or @code{loadPositionFile} option is set,
XBoard
starts each game with the given opening moves or the given position;
otherwise, the games start with the standard initial chess position.
If the @code{saveGameFile} option is set, a move record for the
match is appended to the specified file. If the @code{savePositionFile}
option is set, the final position reached in each game of the match is appended
to the specified file. When the match is over, XBoard
displays the match score and exits. Default: 0 (do not run a match).
@item -mm/-xmm or -matchMode true/false
@cindex mm, option
@cindex matchMode, option
Setting @code{matchMode} to true is equivalent to setting
@code{matchGames} to 1.
@item -sameColorGames n
@cindex sameColorGames, option
Automatically runs an n-game match between two chess engines,
without alternating colors.
Otherwise the same applies as for the @samp{-matchGames} option,
over which it takes precedence if both are specified. (See there.)
Default: 0 (do not run a match).
@item -fcp or -firstChessProgram program
@cindex fcp, option
@cindex firstChessProgram, option
Name of first chess engine.
Default: @file{Fairy-Max}.
@item -scp or -secondChessProgram program
@cindex scp, option
@cindex secondChessProgram, option
Name of second chess engine, if needed.
A second chess engine is started only in Two Machines (match) mode.
Default: @file{Fairy-Max}.
@item -fb/-xfb or -firstPlaysBlack true/false
@cindex fb, option
@cindex firstPlaysBlack, option
In games between two chess engines, firstChessProgram normally plays
white.  If this option is true, firstChessProgram plays black.  In a
multi-game match, this option affects the colors only for the first
game; they still alternate in subsequent games.
@item -fh or -firstHost host
@itemx -sh or -secondHost host
@cindex fh, option
@cindex firstHost, option
@cindex sh, option
@cindex secondHost, option
Hosts on which the chess engines are to run. The default for
each is @file{localhost}. If you specify another host, XBoard
uses @file{rsh} to run the chess engine there. (You can substitute a
different remote shell program for rsh using the @code{remoteShell}
option described below.)
@item -fd or -firstDirectory dir
@itemx -sd or -secondDirectory dir
@cindex fd, option
@cindex firstDirectory, option
@cindex sd, option
@cindex secondDirectory, option
Working directories in which the chess engines are to be run.
The default is "", which means to run the chess engine
in the same working directory as XBoard
itself.  (See the CHESSDIR environment variable.)
This option is effective only when the chess engine is being run
on the local host; it does not work if the engine is run remotely
using the -fh or -sh option.
@item -initString string
@itemx -secondInitString string
@cindex initString, option
@cindex secondInitString, option
The string that is sent to initialize each chess engine for a new game.
Default:

@example
new
random
@end example
@noindent
Setting this option from the command line is tricky, because you must
type in real newline characters, including one at the very end.
In most shells you can do this by
entering a @samp{\} character followed by a newline. It is easier to set
the option from your @file{.Xresources} file; in that case you can
include the character sequence @samp{\n} in the string, and it will
be converted to a newline.

If you change this option, don't remove the @samp{new} 
command; it is required by all chess engines to
start a new game.

You can remove the @samp{random} command if you like; including it
causes GNU Chess 4 to randomize its move selection slightly so that it
doesn't play the same moves in every game.  Even without
@samp{random}, GNU Chess 4 randomizes its choice of moves from its
opening book.  Many other chess engines ignore this command entirely
and always (or never) randomize.

You can also try adding other commands to the initString; see the
documentation of the chess engine you are using for details.
@item -firstComputerString string
@itemx -secondComputerString string
@cindex firstComputerString, option
@cindex secondComputerString, option
The string that is sent to the chess engine if its opponent is another
computer chess engine.  The default is @samp{computer\n}.  Probably the
only useful alternative is the empty string (@samp{}), which keeps the
engine from knowing that it is playing another computer.
@item -reuse/-xreuse or -reuseFirst true/false
@itemx -reuse2/-xreuse2 or -reuseSecond true/false
@cindex reuse, option
@cindex reuseFirst, option
@cindex reuse2, option
@cindex reuseSecond, option
If the option is false,
XBoard kills off the chess engine after every game and starts
it again for the next game.  
If the option is true (the default), 
XBoard starts the chess engine only once
and uses it repeatedly to play multiple games.
Some old chess engines may not work properly when
reuse is turned on, but otherwise games will start faster if it is left on.
@item -firstProtocolVersion version-number
@itemx -secondProtocolVersion version-number
@cindex firstProtocolVersion, option
@cindex secondProtocolVersion, option
This option specifies which version of the chess engine communication
protocol to use.  By default, version-number is 2.  In version 1, the
"protover" command is not sent to the engine; since version 1 is a
subset of version 2, nothing else changes.  Other values for
version-number are not supported.
@item -firstScoreAbs true/false
@itemx -secondScoreAbs true/false
@cindex firstScoreAbs, option
@cindex secondScoreAbs, option
If this option is set, the score reported by the engine is taken to be 
that in favor of white, even when the engine plays black. 
Important when XBoard uses the score for adjudications, or in PGN reporting. 
@item -niceEngines priority
@cindex niceEngines, option
This option allows you to lower the priority of the engine processes, 
so that the generally insatiable hunger for CPU time of chess engines does not interfere so much 
with smooth operation of XBoard (or the rest of your system). 
Negative values could increase the engine priority, which is not recommended.
@item -firstOptions string
@itemx -secondOptions string
@cindex firstOptions, option
@cindex secondOptions, option
The given string is a comma-separated list of (option name=option value) pairs, 
like the following example: "style=Karpov,blunder rate=0". 
If an option announced by the engine at startup through the feature commands of the XBoard/WinBoard protocol 
matches one of the option names (i.e. "style" or "blunder rate"), 
it would be set to the given value (i.e. "Karpov" or 0) 
through a corresponding option command to the engine. 
This provided that the type of the value (text or numeric) matches as well.
@item -firstNeedsNoncompliantFEN string
@itemx -secondNeedsNoncompliantFEN string
@cindex firstNeedsNoncompliantFEN, option
@cindex secondNeedsNoncompliantFEN, option
The castling rights and e.p. fields of the FEN sent to the mentioned engine 
with the setboard command will be replaced by the given string. This can for 
instance be used to run engines that do not understand Chess960 FENs in 
variant fischerandom, to make them at least understand the opening position, 
through setting the string to "KQkq -". (Note you also have to give the e.p. field!) 
Other possible applications are to provide work-arounds for engines that want to see 
castling and e.p. fields in variants that do not have castling or e.p. 
(shatranj, courier, xiangqi, shogi) so that XBoard would normally omit them 
(string = "- -"), or to add variant-specific fields that are not yet supported by XBoard 
(e.g. to indicate the number of checks in 3check).
@item -shuffleOpenings
@cindex shuffleOpenings, option
Forces shuffling of the opening setup in variants that normally have a fixed initial position.
Shufflings are symmetric for black and white, and exempt King and Rooks in variants
with normal castling.
Remains in force until a new variant is selected.
@end table

@node UCI + WB Engine Settings
@section UCI + WB Engine Settings
@cindex Engine Settings
@cindex Settings, Engine
@table @asis
@item -fUCI or -firstIsUCI true/false
@itemx -sUCI or -secondIsUCI true/false
@cindex fUCI, option
@cindex sUCI, option
@cindex firstIsUCI, option
@cindex secondIsUCI, option
Indicates if the mentioned engine executable file is an UCI engine, 
and should be run with the aid of the Polyglot adapter rather than directly. 
Xboard will then pass the other UCI options and engine name to Polyglot 
through a .ini temporary file created for the purpose.
@item -PolyglotDir filename
@cindex PolyglotDir, option
Gives the name of the directory in which the Polyglot adapter for UCI engines expects its files.
Default: "/usr/local/share/polyglot".
@item -usePolyglotBook true/false
@cindex usePolyglotBook, option
Specifies if the Polyglot book should be used.
@item -PolyglotBook filename
@cindex PolyglotBook, option
Gives the filename of the opening book that Polyglot should use. 
From XBoard 4.3.15 on, native XBoard/WinBoard engines will also use the opening book specified here, 
provided the @code{usePolyglotBook} option is set to true,
and the option @code{firstHasOwnBookUCI} or @code{secondHasOwnBookUCI} applying to the engine
is set to false.
The engine will be kept in force mode as long as the current position is in book, 
and XBoard will select the book moves for it. Default "".
@item -fNoOwnBookUCI or -firstXBook or -firstHasOwnBookUCI true/false
@itemx -sNoOwnBookUCI or -secondXBook or -secondHasOwnBookUCI true/false
@cindex fNoOwnBookUCI, option
@cindex sNoOwnBookUCI, option
@cindex firstHasOwnBookUCI, option
@cindex secondHasOwnBookUCI, option
@cindex firstXBook, option
@cindex secondXBook, option
Indicates if the mentioned engine has its own opening book it should play from,
rather than using the external book through XBoard. Default: false.
@item -defaultHashSize n
@cindex defaultHashSize, option
Sets the size of the hash table to n MegaBytes. Together with the EGTB cache size 
this number is also used to calculate the memory setting of XBoard/WinBoard engines, 
for those that support the memory feature of the XBoard/WinBoard protocol. Default: 64.
@item -defaultCacheSizeEGTB n
@cindex defaultCacheSizeEGTB, option
Sets the size of the EGTB cache to n MegaBytes. Together with the hash-table size 
this number is also used to calculate the memory setting of XBoard/WinBoard engines, 
for those that support the memory feature of the XBoard/WinBoard protocol. Default: 4.
@item -defaultPathEGTB filename
@cindex defaultPathEGTB, option
Gives the name of the directory where the end-game tablebases are installed, for UCI engines.
Default: "/usr/local/share/egtb".
@item -egtFormats string
@cindex egtFormats, option
Specifies which end-game tables are installed on the computer, and where. 
The argument is a comma-separated list of format specifications, 
each specification consisting of a format name, a colon, and a directory path name, 
e.g. "nalimov:/usr/local/share/egtb". 
If the name part matches that of a format that the engine requests through a feature command, 
xboard will relay the path name for this format to the engine through an egtpath command. 
One egtpath command for each matching format will be sent. 
Popular formats are "nalimov" DTM tablebases and "scorpio" bitbases.
Default: "".
@end table

@node ICS options
@section ICS options
@cindex ICS options
@cindex Options, ICS
@table @asis
@item -ics/-xics or -internetChessServerMode true/false
@cindex ics, option
@cindex internetChessServerMode, option
Connect with an Internet Chess Server to play chess against its
other users, observe games they are playing, or review games
that have recently finished. Default: false.
@item -icshost or -internetChessServerHost host
@cindex icshost, option
@cindex internetChessServerHost, option
The Internet host name or address of the chess server to connect
to when in ICS mode. Default: @code{chessclub.com}.
Another popular chess server to try is @code{freechess.org}.
If your site doesn't have a working Internet name server, try
specifying the host address in numeric form. 
You may also need
to specify the numeric address when using the icshelper option
with timestamp or timeseal (see below).
@item -icsport or -internetChessServerPort port-number
@cindex icsport, option
@cindex internetChessServerPort, option
The port number to use when connecting to a chess server in ICS
mode. Default: 5000.
@item -icshelper or -internetChessServerHelper prog-name
@cindex icshelper, option
@cindex internetChessServerHelper, option
An external helper program used to communicate with the chess server.
You would set it to "timestamp" for ICC (chessclub.com) or
"timeseal" for FICS (freechess.org), after
obtaining the correct version of timestamp or timeseal for your
computer.  See "help timestamp" on ICC and "help timeseal" on FICS.
This option is shorthand for @code{-useTelnet -telnetProgram program}.
@item -telnet/-xtelnet or -useTelnet true/false
@cindex telnet, option
@cindex useTelnet, option
This option is poorly named; it should be called useHelper.
If set to true, it instructs XBoard to run an external
program to communicate with the Internet Chess Server. 
The program to use is given by the telnetProgram option.
If the option is
false (the default), XBoard opens a TCP socket and uses its own
internal implementation of the telnet protocol to communicate with the
ICS. @xref{Firewalls}.
@item -telnetProgram prog-name
@cindex telnetProgram, option
This option is poorly named; it should be called helperProgram.
It gives the name of the telnet program to be used with
the @code{gateway} and @code{useTelnet} options.  The default is
@file{telnet}. The telnet program is invoked with the value of
@code{internetChessServerHost} as its first argument and the value
of @code{internetChessServerPort} as its second argument.
@xref{Firewalls}.
@item -gateway host-name
@cindex gateway, option
If this option is set to a host name, XBoard communicates with the
Internet Chess Server by using @file{rsh} to run
the @code{telnetProgram} on the given host,
instead of using its own internal implementation
of the telnet protocol. You can substitute a different remote shell
program for @file{rsh} using the @code{remoteShell} option described below.
@xref{Firewalls}.
@item -internetChessServerCommPort or -icscomm dev-name
@cindex internetChessServerCommPort, option
@cindex icscomm, option
If this option is set, XBoard communicates with the ICS through
the given character I/O device instead of opening a TCP connection.
Use this option if your system does not have any kind of
Internet connection itself (not even a SLIP or PPP connection),
but you do have dial-up access (or a hardwired terminal line) to
an Internet service provider from which you can telnet to the ICS.

The support for this option in XBoard is minimal. You need to
set all communication parameters and tty modes before you enter
XBoard.

Use a script something like this:

@example
stty raw -echo 9600 > /dev/tty00
xboard -ics -icscomm /dev/tty00
@end example

Here replace @samp{/dev/tty00} with the name of the device that your
modem is connected to. You might have to add several more
options to these stty commands. See the man pages for @file{stty}
and @code{tty} if you run into problems. Also, on many systems stty
works on its standard input instead of standard output, so you
have to use @samp{<} instead of @samp{>}.

If you are using linux, try starting with the script below.
Change it as necessary for your installation.

@example
#!/bin/sh -f
# configure modem and fire up XBoard

# configure modem
(
  stty 2400 ; stty raw ; stty hupcl ; stty -clocal
  stty ignbrk ; stty ignpar ; stty ixon ; stty ixoff
  stty -iexten ; stty -echo
) < /dev/modem
xboard -ics -icscomm /dev/modem
@end example
@noindent
After you start XBoard in this way, type whatever commands are
necessary to dial out to your Internet provider and log in.
Then telnet to ICS, using a command like
@kbd{telnet chessclub.com 5000}.
Important: See the paragraph below about extra echoes, 
in @ref{Limitations}.
@item -icslogon or -internetChessServerLogonScript file-name
@cindex icslogon, option
@cindex internetChessServerLogonScript, option
@cindex .icsrc
Whenever XBoard connects to the Internet Chess Server,
if it finds a file with the name given in this option, it feeds the
file's contents to the ICS as commands. The default file name
is @file{.icsrc}.
Usually the first two lines of the file should be
your ICS user name and password.
The file can be either in $CHESSDIR, in XBoard's working
directory if CHESSDIR is not set, or in your home directory.
@item -msLoginDelay delay
@cindex msLoginDelay, option
If you experience trouble logging on to an ICS when using the
@code{-icslogon} option, inserting some delay between characters
of the logon script may help. This option adds @code{delay}
milliseconds of delay between characters. Good values to try
are 100 and 250.
@item -icsinput/-xicsinput or -internetChessServerInputBox true/false
@cindex icsinput, option
@cindex internetChessServerInputBox, option
Sets the ICS Input Box menu option. @xref{Mode Menu}. Default: false.
@item -autocomm/-xautocomm or -autoComment true/false
@cindex autocomm, option
@cindex autoComment, option
Sets the Auto Comment menu option. @xref{Options Menu}. Default: false.
@item -autoflag/-xautoflag or -autoCallFlag true/false
@cindex autoflag, option
@cindex autoCallFlag, option
Sets the Auto Flag menu option.  @xref{Options Menu}. Default: false.
@item -autobs/-xautobs or -autoObserve true/false
@cindex autobs, option
@cindex autoObserve, option
Sets the Auto Observe menu option.  @xref{Options Menu}. Default: false.
@item -autoKibitz
@cindex autoKibitz, option
Enables kibitzing of the engines last thinking output (depth, score, time, speed, PV) 
before it moved
to the ICS, in zippy mode. The option @code{showThinking} must be switched on for 
this option to work.
Also diverts similar kibitz information of an opponent engine that is playing you 
through the ICS to the engine-output window, as if the engine was playing locally.
@item -seekGraph true/false or -sg
@cindex seekGraph, option
@cindex sg, option
Enables displaying of the seek graph by left-clicking the board when
you are logged on to an ICS and currently idle.
The seek graph show all players currently seeking games on the ICS,
plotted according to their rating and the time control of the game they seek,
in three different colors (for rated, unrated and wild games).
Computer ads are displayed as squares, human ads are dots.
Default: false.
@item -autoRefresh true/false
@cindex autoRefresh, option
Enables automatic updating of the seek graph,
by having the ICS send a running update of all newly placed
and removed seek ads.
This consumes a substantial amount of communication bandwidth,
and is only supported for FICS and ICC.
Default: false.
@item -backgroundObserve true/false
@cindex backgroundObserve, option
When true, boards sent to you by the ICS from other games while you are playing
(e.g. because you are observing them)
will not be automatically displayed.
Only a summary of time left and material of both players will appear
in the message field above the board.
XBoard will remember the last board it has received this way,
and will display it in stead of the position in your own game
when you press the right mouse button.
No other information is stored on such games observed in the background;
you cannot save such a game later, or step through its moves.
This feature is provided solely for the benefit of bughouse players,
to enable them to peek at their partner's game without the need
to logon twice.
Default: false.
@item -dualBoard true/false
@cindex dualBoard, option
In combination with -backgroundObserve true, this option will display
the board of the background game side by side with that of your own game,
so you can have it in view permanently.
Any board or holdings info coming in will be displayed on the secondary
board immediately.
This feature is still experimental and largely unfinished.
There is no animation or highlighting of moves on the secondary board.
Default: false.
@item -oneClickMove true/false
@cindex oneClickMove, option
When set, this option allows you to enter moves by only clicking the to-
or from-square, when only a single legal move to or from that square
is possible.
Double-clicking a piece (or clicking an already selected piece)
will instruct that piece to make the only capture it can legally do.
Defaut: false.
@item -moves/-xmoves or -getMoveList true/false
@cindex moves, option
@cindex getMoveList, option
Sets the Get Move List menu option.  @xref{Options Menu}.  Default: true.
@item -alarm/-xalarm or -icsAlarm true/false
@cindex alarm, option
@cindex icsAlarm, option
Sets the ICS Alarm menu option.  @xref{Options Menu}. Default: true.
@item -icsAlarmTime ms
@cindex icsAlarmTime, option
Sets the time in milliseconds for the ICS Alarm menu option.
@xref{Options Menu}. Default: 5000.
@item lowTimeWarning true/false
@cindex lowTimeWarning, option
Controls a color change of the board as a warning your time is running out.
@xref{Options Menu}. Default: false.
@item -pre/-xpre \fRor\fB -premove true/false
@cindex pre, option
@cindex premove, option
Sets the Premove menu option. @xref{Options Menu}. Default: true.
@item -quiet/-xquiet or -quietPlay true/false
@cindex quiet, option
@cindex quietPlay, option
Sets the Quiet Play menu option.  @xref{Options Menu}.  Default: false.
@item -colorizeMessages or -colorize
@cindex Colors
@cindex colorize, option
Setting colorizeMessages
to true tells XBoard to colorize the messages received from
the ICS.  Colorization works only if your xterm 
supports ISO 6429 escape sequences for changing text colors.
@item -colorShout foreground,background,bold
@itemx -colorSShout foreground,background,bold
@itemx -colorChannel1 foreground,background,bold
@itemx -colorChannel foreground,background,bold
@itemx -colorKibitz foreground,background,bold
@itemx -colorTell foreground,background,bold
@itemx -colorChallege foreground,background,bold
@itemx -colorRequest foreground,background,bold
@itemx -colorSeek foreground,background,bold
@itemx -colorNormal foreground,background,bold
@cindex Colors
@cindex colorShout, option
@cindex colorSShout, option
@cindex colorChannel1, option
@cindex colorChannel, option
@cindex colorKibitz, option
@cindex colorTell, option
@cindex colorChallenge, option
@cindex colorRequest, option
@cindex colorSeek, option
@cindex colorNormal, option
These options set the colors used when colorizing ICS messages.
All ICS messages are grouped into one of these categories:
shout, sshout, channel 1, other channel, kibitz, tell, challenge, 
request (including abort, adjourn, draw, pause, and takeback), or
normal (all other messages).  

Each foreground or background argument can be one of the following:
black, red, green, yellow, blue, magenta, cyan, white, or default.
Here ``default'' means the default foreground or background color of
your xterm.  Bold can be 1 or 0.  If background is omitted, ``default''
is assumed; if bold is omitted, 0 is assumed.

Here is an example of how to set the colors in your @file{.Xresources} file.
The colors shown here are the default values; you will get
them if you turn @code{-colorize} on without specifying your own colors.

@example
xboard*colorizeMessages: true   
xboard*colorShout: green
xboard*colorSShout: green, black, 1
xboard*colorChannel1: cyan
xboard*colorChannel: cyan, black, 1
xboard*colorKibitz: magenta, black, 1
xboard*colorTell: yellow, black, 1
xboard*colorChallenge: red, black, 1
xboard*colorRequest: red
xboard*colorSeek: blue
xboard*colorNormal: default
@end example
@item -soundProgram progname
@cindex soundProgram, option
@cindex Sounds
If this option is set to a sound-playing program that is installed and
working on your system, XBoard can play sound files when certain
events occur, listed below.  The default program name is "play".  If
any of the sound options is set to "$", the event rings the terminal
bell by sending a ^G character to standard output, instead of playing
a sound file.  If an option is set to the empty string "", no sound is
played for that event.
@item -soundShout filename
@itemx -soundSShout filename
@itemx -soundChannel filename
@itemx -soundKibitz filename
@itemx -soundTell filename
@itemx -soundChallenge filename
@itemx -soundRequest filename
@itemx -soundSeek filename
@cindex soundShout, option
@cindex soundSShout, option
@cindex soundChannel, option
@cindex soundKibitz, option
@cindex soundTell, option
@cindex soundChallenge, option
@cindex soundRequest, option
@cindex soundSeek, option
These sounds are triggered in the same way as the colorization events
described above.  They all default to "", no sound.  They are played
only if the colorizeMessages is on.
@item -soundMove filename
@cindex soundMove, option
This sound is used by the Move Sound menu option.  Default: "$".
@item -soundIcsAlarm filename
@cindex soundIcsAlarm, option
This sound is used by the ICS Alarm menu option.  Default: "$".
@item -soundIcsWin filename
@cindex soundIcsWin, option
This sound is played when you win an ICS game.  Default: "" (no sound).
@item -soundIcsLoss filename
@cindex soundIcsLoss, option
This sound is played when you lose an ICS game.  Default: "" (no sound).
@item -soundIcsDraw filename
@cindex soundIcsDraw, option
This sound is played when you draw an ICS game.  Default: "" (no sound).
@item -soundIcsUnfinished filename
@cindex soundIcsUnfinished, option
This sound is played when an ICS game that you are participating in is
aborted, adjourned, or otherwise ends inconclusively.  Default: "" (no
sound).

Here is an example of how to set the sounds in your @file{.Xresources} file:

@example
xboard*soundShout: shout.wav
xboard*soundSShout: sshout.wav
xboard*soundChannel1: channel1.wav
xboard*soundChannel: channel.wav
xboard*soundKibitz: kibitz.wav
xboard*soundTell: tell.wav
xboard*soundChallenge: challenge.wav
xboard*soundRequest: request.wav
xboard*soundSeek: seek.wav
xboard*soundMove: move.wav
xboard*soundIcsWin: win.wav
xboard*soundIcsLoss: lose.wav
xboard*soundIcsDraw: draw.wav
xboard*soundIcsUnfinished: unfinished.wav
xboard*soundIcsAlarm: alarm.wav
@end example
@item -dropMenu true|false
@cindex dropMenu, option
This option allows you to emulate old behavior, 
where the right mouse button brings up the (now deprecated) drop menu 
rather than displaying the position at the end of the principal variation. 
Default: False.
@end table

@node Load and Save options
@section Load and Save options
@cindex Options, Load and Save
@cindex Load and Save options
@table @asis
@item -lgf or -loadGameFile file
@itemx -lgi or -loadGameIndex index
@cindex lgf, option
@cindex loadGameFile, option
@cindex lgi, option
@cindex loadGameIndex, option
If the @code{loadGameFile} option is set, XBoard loads the specified
game file at startup. The file name @file{-} specifies the standard
input. If there is more than one game in the file, XBoard
pops up a menu of the available games, with entries based on their PGN 
(Portable Game Notation) tags.
If the @code{loadGameIndex} option is set to @samp{N}, the menu is suppressed
and the N th game found in the file is loaded immediately.
The menu is also suppressed if @code{matchMode} is enabled or if the game file
is a pipe; in these cases the first game in the file is loaded immediately.
Use the @file{pxboard} shell script provided with XBoard if you
want to pipe in files containing multiple games and still see the menu.
If the loadGameIndex specifies an index -1, this triggers auto-increment
of the index in @code{matchMode}, which means that after every game the
index is incremented by one, causing each game of the match to be played
from the next game in the file. Similarly, specifying an index value of -2
causes the index to be incremented every two games, so that each game
in the file is used twice (with reversed colors).
The @code{rewindIndex} option causes the index to be reset to the
first game of the file when it has reached a specified value.
@item -rewindIndex n
Causes a position file or game file to be rewound to its beginning after n
positions or games in auto-increment @code{matchMode}. 
See @code{loadPositionIndex} and @code{loadGameIndex}.
default: 0 (no rewind).
@item -td or -timeDelay seconds
@cindex td, option
@cindex timeDelay, option
Time delay between moves during @samp{Load Game}. Fractional seconds
are allowed; try @samp{-td 0.4}. A time delay value of -1 tells
XBoard not to step through game files automatically. Default: 1
second.
@item -sgf or -saveGameFile file
@cindex sgf, option
@cindex saveGameFile, option
If this option is set, XBoard appends a record of every game
played to the specified file. The file name @file{-} specifies the
standard output.
@item -autosave/-xautosave or -autoSaveGames true/false
@cindex autosave, option
@cindex autoSaveGames, option
Sets the Auto Save menu option.  @xref{Options Menu}.  Default: false.
Ignored if @code{saveGameFile} is set.
@item -lpf or -loadPositionFile file
@itemx -lpi or -loadPositionIndex index
@cindex lpf, option
@cindex loadPositionFile, option
@cindex lpi, option
@cindex loadPositionIndex, option
If the @code{loadPositionFile} option is set, XBoard loads the
specified position file at startup. The file name @file{-} specifies the
standard input. If the @code{loadPositionIndex} option is set to N,
the Nth position found in the file is loaded; otherwise the
first position is loaded.
If the loadPositionIndex specifies an index -1, this triggers auto-increment
of the index in @code{matchMode}, which means that after every game the
index is incremented by one, causing each game of the match to be played
from the next position in the file. Similarly, specifying an index value of -2
causes the index to be incremented every two games, so that each position
in the file is used twice (with the engines playing opposite colors).
The @code{rewindIndex} option causes the index to be reset to the
first position of the file when it has reached a specified value.
@item -spf or -savePositionFile file
@cindex spf, option
@cindex savePositionFile, option
If this option is set, XBoard appends the final position reached
in every game played to the specified file. The file name @file{-}
specifies the standard output.
@item -pgnExtendedInfo true/false
@cindex pgnExtendedInfo, option`
If this option is set, XBoard saves depth, score and time used for each 
move that the engine found as a comment in the PGN file.
Default: false.
@item -pgnEventHeader string
@cindex pgnEventHeader, option`
Sets the name used in the PGN event tag to string. 
Default: "Computer Chess Game".
@item -saveOutOfBookInfo true/false
@cindex saveOutOfBookInfo, option`
Include the information on how the engine(s) game out of its opening book 
in a special 'annotator' tag with the PGN file.
@item -oldsave/-xoldsave or -oldSaveStyle true/false
@cindex oldsave, option
@cindex oldSaveStyle, option
Sets the Old Save Style menu option.  @xref{Options Menu}.  Default: false.
@item -gameListTags string
@cindex gameListTags, option
The character string lists the PGN tags that should be printed in the
Game List, and their order. The meaning of the codes is e=event,
s=site, d=date, o=round, p=players, r=result, w=white Elo, b=black Elo,
t=time control, v=variant, a=out-of-book info, c=result comment.
Default: "eprd"
@item -ini or -settingsFile filename
@itemx -saveSettingsFile filename
@itemx @@filename
@cindex saveSettingsFile, option
@cindex SettingsFile, option
@cindex init, option
@cindex at sign, option
When XBoard encounters an option -settingsFile (or -ini for short),
or @@filename, it tries to read the mentioned file,
and substitutes the contents of it (presumaby more command-line options)
in place of the option.
In the case of -ini or -settingsFile, the name of a successfully read
settings file is also remembered as the file to use for saving settings
(automatically on exit, or on user command).
An option of the form @@filename does not affect saving.
The option -saveSettingsFile does specify a name of the file to use
for saving, without reading any options from it, and is thus also effective
when the file did not exist yet.
So the settings will be saved to the file specified in the last
-saveSettingsFile or succesfull -settingsFile / -ini command,
if any, and in /etc/xboard/xboard.conf otherwise.
Usualy the latter is only accessible for the system administrator, though, 
and will be used to contain system-wide default setings, amongst which
a -saveSettingsFile and -settingsFile options to specify a settings file
accessible to the individual user, such as ~/.xboardrc in the user's
home directory.
@end table

@node User interface options
@section User interface options
@cindex User interface options
@cindex Options, User interface
@table @asis
@item -display
@itemx -geometry
@itemx -iconic
@cindex display, option
@cindex geometry, option
@cindex iconic, option
These and most other standard Xt options are accepted.
@item -noGUI
@cindex noGUI, option
Suppresses all GUI functions of XBoard 
(to speed up automated ultra-fast engine-engine games, which you don’t want to watch). 
There will be no board or clock updates, no printing of moves, 
and no update of the icon on the task bar in this mode.
@item -movesound/-xmovesound or -ringBellAfterMoves true/false
@cindex movesound, option
@cindex bell, option
@cindex ringBellAfterMoves, option
Sets the Move Sound menu option.  @xref{Options Menu}.  Default: false.
For compatibility with old XBoard versions, -bell/-xbell are also 
accepted as abbreviations for this option.
@item -exit/-xexit or -popupExitMessage true/false
@cindex exit, option
@cindex popupExitMessage, option
Sets the Popup Exit Message menu option.  @xref{Options Menu}. Default: true.
@item -popup/-xpopup or -popupMoveErrors true/false
@cindex popup, option
@cindex popupMoveErrors, option
Sets the Popup Move Errors menu option.  @xref{Options Menu}. Default: false.
@item -queen/-xqueen or -alwaysPromoteToQueen true/false
@cindex queen, option
@cindex alwaysPromoteToQueen, option
Sets the Always Queen menu option.  @xref{Options Menu}.  Default: false.
@item -legal/-xlegal or -testLegality true/false
@cindex legal, option
@cindex testLegality, option
Sets the Test Legality menu option.  @xref{Options Menu}.  Default: true.
@item -size or -boardSize (sizeName | n1,n2,n3,n4,n5,n6,n7)
@cindex size, option
@cindex boardSize, option
@cindex board size
Determines how large the board will be, by selecting the pixel size
of the pieces and setting a few related parameters.
The sizeName can be one of: Titanic, giving 129x129 pixel pieces,
Colossal 116x116, Giant 108x108, Huge 95x95, Big 87x87, Large 80x80, Bulky 72x72,
Medium 64x64, Moderate 58x58, Average 54x54, Middling 49x49, Mediocre
45x45, Small 40x40, Slim 37x37, Petite 33x33, Dinky 29x29, Teeny 25x25,
or Tiny 21x21.
Orthodox pieces of all these sizes are built into XBoard.
Other sizes can
be used if you have them; see the pixmapDirectory and bitmapDirectory
options.
Complete sets of un-orthodox pieces are only provided in sizes
Bulky, Middling and (to a lesser extent) Petite;
Archbishop, Marshall and Amazon are also available in all sizes between
Bulky and Petite.
When no bitmap is available, the piece will be displayed as Amazon or King.
The default depends on the size of your screen; it is approximately the
largest size that will fit without clipping.

You can select other sizes or vary other layout parameters by providing
a list of comma-separated values (with no spaces) as the argument.
You do not need to provide all the values; for any you omit from the
end of the list, defaults are taken from the nearest built-in size.
The value @code{n1} gives the piece size, @code{n2} the width of the
black border
between squares, @code{n3} the desired size for the 
clockFont, @code{n4} the desired size for the coordFont,
@code{n5} the desired size for the default font,
@code{n6} the smallLayout flag (0 or 1), 
and @code{n7} the tinyLayout flag (0 or 1).  
All dimensions are in pixels.
If the border between squares is eliminated (0 width), the various
highlight options will not work, as there is nowhere to draw the highlight.
If smallLayout is 1 and @code{titleInWindow} is true, 
the window layout is rearranged to make more room for the title.
If tinyLayout is 1, the labels on the menu bar are abbreviated
to one character each and the buttons in the button bar are made narrower.
@item -coords/-xcoords or -showCoords true/false
@cindex coords, option
@cindex showCoords, option
Sets the Show Coords menu option.  @xref{Options Menu}.  Default: false.
The @code{coordFont} option specifies what font to use.
@item -autoraise/-xautoraise or -autoRaiseBoard true/false
@cindex autoraise, option
@cindex autoRaiseBoard, option
Sets the Auto Raise Board menu option.  @xref{Options Menu}.  Default: true.
@item -autoflip/-xautoflip or -autoFlipView true/false
@cindex autoflip, option
@cindex autoFlipView, option
Sets the Auto Flip View menu option.  @xref{Options Menu}.  Default: true.
@item -flip/-xflip or -flipView true/false
@cindex flip, option
@cindex flipView, option
If Auto Flip View is not set, or if you are observing but not participating
in a game, then the positioning of the board at the start of each game
depends on the flipView option.  If flipView is false (the default),
the board is positioned so that the white pawns move from the bottom to the
top; if true, the black pawns move from the bottom to the top.
In any case, the Flip menu option (see @ref{Options Menu})
can be used to flip the board after
the game starts.
@item -title/-xtitle or -titleInWindow true/false
@cindex title, option
@cindex titleInWindow, option
If this option is true, XBoard displays player names (for ICS
games) and game file names (for @samp{Load Game}) inside its main
window. If the option is false (the default), this information is
displayed only in the window banner. You probably won't want to
set this option unless the information is not showing up in the
banner, as happens with a few X window managers.
@item -buttons/-xbuttons or -showButtonBar True/False
@cindex buttons, option
@cindex showButtonBar, option
If this option is False, xboard omits the [<<] [<] [P] [>] [>>] button
bar from the window, allowing the message line to be wider.  You can
still get the functions of these buttons using the menus or their keyboard
shortcuts.  Default: true.
@item -mono/-xmono or -monoMode true/false
@cindex mono, option
@cindex monoMode, option
Determines whether XBoard displays its pieces and squares with
two colors (true) or four (false). You shouldn't have to
specify @code{monoMode}; XBoard will determine if it is necessary.
@item -showTargetSquares true/false
@cindex showTargetSquares, option
Determines whether XBoard can highlight the squares a piece has
legal moves to, when you grab that piece with the mouse.
If this option is set, this feature can be controlled through
the Highlight Dragging menu item.
@item -flashCount count
@itemx -flashRate rate
@itemx -flash/-xflash
@cindex flashCount, option
@cindex flashRate, option
@cindex flash, option
@cindex xflash, option
These options enable flashing of pieces when they
land on their destination square.
@code{flashCount}
tells XBoard how many times to flash a piece after it
lands on its destination square.
@code{flashRate}
controls the rate of flashing (flashes/sec).
Abbreviations:
@code{flash}
sets flashCount to 3.
@code{xflash}
sets flashCount to 0.
Defaults:  flashCount=0 (no flashing), flashRate=5.
@item -highlight/-xhighlight or -highlightLastMove true/false
@cindex highlight, option
@cindex highlightLastMove, option
Sets the Highlight Last Move menu option. @xref{Options Menu}. Default: false.
@item -blind/-xblind or -blindfold true/false
@cindex blind, option
@cindex blindfold, option
Sets the Blindfold menu option.  @xref{Options Menu}.  Default: false.
@item -clockFont font
@cindex clockFont, option
@cindex Font, clock
The font used for the clocks. If the option value is a pattern
that does not specify the font size, XBoard tries to choose an
appropriate font for the board size being used.
Default: -*-helvetica-bold-r-normal--*-*-*-*-*-*-*-*.
@item -coordFont font
@cindex coordFont, option
@cindex Font, coordinates
The font used for rank and file coordinate labels if @code{showCoords}
is true. If the option value is a pattern that does not specify
the font size, XBoard tries to choose an appropriate font for
the board size being used.
Default: -*-helvetica-bold-r-normal--*-*-*-*-*-*-*-*.
@item -font font
@cindex font, option
@cindex Font
The font used for popup dialogs, menus, comments, etc.
If the option value is a pattern that does not specify
the font size, XBoard tries to choose an appropriate font for
the board size being used.
Default: -*-helvetica-medium-r-normal--*-*-*-*-*-*-*-*.
@item -fontSizeTolerance tol
@cindex fontSizeTolerance, option
In the font selection algorithm, a nonscalable font will be preferred
over a scalable font if the nonscalable font's size differs
by @code{tol} pixels
or less from the desired size.  A value of -1 will force
a scalable font to always be used if available; a value of 0 will
use a nonscalable font only if it is exactly the right size; 
a large value (say 1000) will force a nonscalable font to always be
used if available.  Default: 4.
@item -bm or -bitmapDirectory dir
@itemx -pixmap or -pixmapDirectory dir
@cindex bm, option
@cindex bitmapDirectory, option
@cindex pixmap, option
@cindex pixmapDirectory, option
These options control what piece images xboard uses.  The XBoard
distribution includes one set of pixmap pieces in xpm format, in the
directory @file{pixmaps}, and one set of bitmap pieces in xbm format,
in the directory @file{bitmaps}.  Pixmap
pieces give a better appearance on the screen: the white pieces have
dark borders, and the black pieces have opaque internal details.  With
bitmaps, neither piece color has a border, and the internal details
are transparent; you see the square color or other background color
through them.

If XBoard is configured and compiled on a system that includes libXpm,
the X pixmap library, the xpm pixmap pieces are compiled in as the
default.  A different xpm piece set can be selected at runtime with
the @code{pixmapDirectory} option, or a bitmap piece set can be selected
with the @code{bitmapDirectory} option.

If XBoard is configured and compiled on a system that does not include
libXpm (or the @code{--disable-xpm} option is given to the configure
program), the bitmap pieces are compiled in as the default.  It is not
possible to use xpm pieces in this case, but pixmap pieces in another
format called "xim" can be used by giving the @code{pixmapDirectory} option.
Or again, a different bitmap piece set can be selected with the
@code{bitmapDirectory} option.

Files in the @code{bitmapDirectory} must be named as follows:
The first character of a piece bitmap name gives the piece it 
represents (@samp{p}, @samp{n}, @samp{b}, @samp{r}, @samp{q}, or @samp{k}),
the next characters give the size in pixels, the
following character indicates whether the piece is
solid or outline (@samp{s} or @samp{o}),
and the extension is @samp{.bm}.
For example, a solid 80x80 knight would be named @file{n80s.bm}.
The outline bitmaps are used only in monochrome mode.
If bitmap pieces are compiled in and the bitmapDirectory is missing
some files, the compiled in pieces are used instead.

If the bitmapDirectory option is given,
it is also possible to replace xboard's icons and menu checkmark,
by supplying files named @file{icon_white.bm}, @file{icon_black.bm}, and
@file{checkmark.bm}.

For more information about pixmap pieces and how to get additional
sets, see @ref{zic2xpm} below.
@item -whitePieceColor color
@itemx -blackPieceColor color
@itemx -lightSquareColor color
@itemx -darkSquareColor color
@itemx -highlightSquareColor color
@itemx -lowTimeWarningColor color
@cindex Colors
@cindex whitePieceColor, option
@cindex blackPieceColor, option
@cindex lightSquareColor, option
@cindex darkSquareColor, option
@cindex highlightSquareColor, option
@cindex lowTimeWarningColor, option
Colors to use for the pieces, squares, and square highlights.
Defaults:

@example
-whitePieceColor       #FFFFCC
-blackPieceColor       #202020
-lightSquareColor      #C8C365
-darkSquareColor       #77A26D
-highlightSquareColor  #FFFF00
-premoveHighlightColor #FF0000
-lowTimeWarningColor   #FF0000
@end example

On a grayscale monitor you might prefer:

@example
-whitePieceColor       gray100
-blackPieceColor       gray0
-lightSquareColor      gray80
-darkSquareColor       gray60
-highlightSquareColor  gray100
-premoveHighlightColor gray70
-lowTimeWarningColor   gray70
@end example
@item -drag/-xdrag or -animateDragging true/false
@cindex drag, option
@cindex animateDragging, option
Sets the Animate Dragging menu option. @xref{Options Menu}.  Default: true.
@item -animate/-xanimate or -animateMoving true/false
@cindex animate, option
@cindex animateMoving, option
Sets the Animate Moving menu option. @xref{Options Menu}.  Default: true.
@item -animateSpeed n
@cindex -animateSpeed, option
Number of milliseconds delay between each animation frame when Animate
Moves is on.
@item -autoDisplayComment true/false
@itemx -autoDisplayTags true/false
@cindex -autoDisplayComment, option
@cindex -autoDisplayTags, option
If set to true, these options cause the window with the move comments,
and the window with PGN tags, respectively, to pop up automatically when
such tags or comments are encountered during the replaying a stored or
loaded game.  Default: true.
@item -pasteSelection true/false
@cindex -pasteSelection, option
If this option is set to true, the Paste Position and Paste Game
options paste from the currently selected text.  If false, they paste
from the clipboard.  Default: false.
@end table

@node Adjudication Options
@section Adjudication Options
@cindex Options, adjudication
@table @asis
@item -adjudicateLossThreshold n
@cindex adjudicateLossThreshold, option
If the given value is non-zero, XBoard adjudicates the game as a loss 
if both engines agree for a duration of 6 consecutive ply that the score 
is below the given score threshold for that engine. Make sure the score 
is interpreted properly by XBoard, 
using @code{-firstScoreAbs} and @code{-secondScoreAbs} if needed. 
Default: 0 (no adjudication)
@item -adjudicateDrawMoves n
@cindex adjudicateDrawMoves, option
If the given value is non-zero, XBoard adjudicates the game as a draw 
if after the given number of moves it was not yet decided. Default: 0 (no adjudication)
@item -checkMates true/false
@cindex checkMates, option
If this option is set, XBoard detects all checkmates and stalemates, 
and ends the game as soon as they occur. 
Legality-testing must be switched on for this option to work.
Default: true
@item -testClaims true/false
@cindex testClaims, option
If this option is set, XBoard verifies all result claims made by engines, 
and those who send false claims will forfeit the game because of it. 
Legality-testing must be switched on for this option to work. Default: true
@item -materialDraws true/false
@cindex materialDraws, option
If this option is set, XBoard adjudicates games as draws when there is 
no sufficient material left to inflict a checkmate. 
This applies to KBKB with like bishops (any number, actually), and to KBK, KNK and KK. 
Legality-testing must be switched on for this option to work. Default: true
@item -trivialDraws true/false
@cindex trivialDraws, option
If this option is set, XBoard adjudicates games as draws that cannot be 
usually won without opponent cooperation. This applies to KBKB with unlike bishops, 
and to KBKN, KNKN, KNNK, KRKR and KQKQ. The draw is called after 6 ply into these end-games, 
to allow quick mates that can occur in some exceptional positions to be found by the engines. 
KQKQ does not really belong in this category, and might be taken out in the future. 
(When bitbase-based adjudications are implemented.) 
Legality-testing must be on for this option to work. Default: false
@item -ruleMoves n
@cindex ruleMoves, option
If the given value is non-zero, XBoard adjudicates the game as a draw after the given 
number of consecutive reversible moves. Engine draw claims are always accepted after 50 moves, 
irrespective of the given value of n.
@item -repeatsToDraw n
If the given value is non-zero, xboard adjudicates the game as a draw if a position 
is repeated the given number of times. Engines draw claims are always accepted after 3 repeats, 
(on the 3rd occurrence, actually), irrespective of the value of n. 
Beware that positions that have different castling or en-passant rights do not count 
as repeats, XBoard is fully e.p. and castling aware!
@end table

@node Other options
@section Other options
@cindex Options, miscellaneous
@table @asis
@item -ncp/-xncp or -noChessProgram true/false
@cindex ncp, option
@cindex noChessProgram, option
If this option is true, XBoard acts as a passive chessboard; it
does not start a chess engine at all. Turning on this option
also turns off clockMode. Default: false.
@item -mode or -initialMode modename
@cindex mode, option
@cindex initalMode, option
If this option is given, XBoard selects the given modename
from the Mode menu after starting and (if applicable) processing the
loadGameFile or loadPositionFile option. Default: "" (no selection). 
Other supported values are 
MachineWhite, MachineBlack, TwoMachines, Analysis, 
AnalyzeFile, EditGame, EditPosition, and Training.
@item -variant varname
@cindex variant, option
Activates preliminary, partial support for playing chess variants
against a local engine or editing variant games.  This flag is not
needed in ICS mode.  Recognized variant names are:

@example
normal        Normal chess
wildcastle    Shuffle chess, king can castle from d file
nocastle      Shuffle chess, no castling allowed
fischerandom  Fischer Random shuffle chess
bughouse      Bughouse, ICC/FICS rules
crazyhouse    Crazyhouse, ICC/FICS rules
losers        Lose all pieces or get mated (ICC wild 17)
suicide       Lose all pieces including king (FICS)
giveaway      Try to have no legal moves (ICC wild 26)
twokings      Weird ICC wild 9
kriegspiel    Opponent's pieces are invisible
atomic        Capturing piece explodes (ICC wild 27)
3check        Win by giving check 3 times (ICC wild 25)
shatranj      An ancient precursor of chess (ICC wild 28)
xiangqi       Chinese Chess (on a 9x10 board)
shogi         Japanese Chess (on a 9x9 board & piece drops) 
capablanca    Capablanca Chess (10x8 board, with Archbishop 
              and Chancellor pieces)
gothic        similar, with a better initial position
caparandom    An FRC-like version of Capablanca Chess (10x8) 
janus         A game with two Archbishops (10x8 board)
courier       Medieval intermediate between shatranj and 
              modern Chess (on 12x8 board) 
falcon        Patented 10x8 variant with two Falcon pieces
berolina      Pawns capture straight ahead, and move diagonal 
cylinder      Pieces wrap around the board edge
knightmate    King moves as Knight, and vice versa 
super         Superchess (shuffle variant with 4 exo-pieces)
makruk        Thai Chess (shatranj-like, P promotes on 6th rank)
fairy         A catchall variant in which all piece types 
              known to XBoard can participate (8x8)
unknown       Catchall for other unknown variants
@end example

NOT ALL BOARDSIZES PROVIDE A COMPLETE SET OF BUILT-IN BITMAPS FOR ALL
UN-ORTHODOX PIECES, though. Only in @code{boardSize} middling and bulky
all 22 piece types are provided, while -boardSize petite has most
of them. Archbishop, Chancellor and Amazon are supported in every
size from petite to bulky. Kings or Amazons are substituted for
missing bitmaps. You can still play variants needing un-orthodox
pieces in other board sizes providing your own bitmaps through the
@code{bitmapDirectory} or @code{pixmapDirectory} options.

In the shuffle variants, XBoard now does shuffle the pieces, although
you can still do it by hand using Edit Position.  Some variants are
supported only in ICS mode, including bughouse, and
kriegspiel.  The winning/drawing conditions in crazyhouse (off-board
interposition on mate) are not fully understood, but losers, suicide, 
giveaway, atomic, and 3check should be OK.
Berolina and cylinder chess can only be played with legality testing off.
In crazyhouse, XBoard now does keep
track of off-board pieces.  In shatranj it does implement the baring
rule when mate detection is switched on.
@item -boardHeight N
@cindex boardHeight, option
Allows you to set a non-standard number of board ranks in any variant. 
If the height is given as -1, the default height for the variant is used.
Default: -1
@item -boardWidth N
@cindex boardWidth, option
Allows you to set a non-standard number of board files in any variant. 
If the width is given as -1, the default width for the variant is used. 
With a non-standard width, the initial position will always be an empty board, 
as the usual opening array will not fit.
Default: -1
@item -holdingsSize N
@cindex holdingsSize, option
Allows you to set a non-standard size for the holdings in any variant. 
If the size is given as -1, the default holdings size for the variant is used. 
The first N piece types will go into the holdings on capture, and you will be 
able to drop them on the board in stead of making a normal move. If size equals 0, 
there will be no holdings.
Default: -1
@item -defaultFrcPosition N
@cindex defaultFrcPosition, option
Specifies the number of the opening position in shuffle games like Chess960. 
A value of -1 means the position is randomly generated by XBoard
at the beginning of every game.
Default: -1
@item -pieceToSquareTable string
@cindex pieceToSquareTable, option
The characters that are used to represent the piece types XBoard knows in FEN 
diagrams and SAN moves. The string argument has to have an even length 
(or it will be ignored), as white and black pieces have to be given separately 
(in that order). The last letter for each color will be the King. 
The letters before that will be PNBRQ and then a whole host of fairy pieces 
in an order that has not fully crystallized yet (currently FEACWMOHIJGDVSLU, 
F=Ferz, Elephant, A=Archbishop, C=Chancellor, W=Wazir, M=Commoner, O=Cannon, 
H=Nightrider). You should list at least all pieces that occur in the variant 
you are playing. If you have less than 44 characters in the string, the pieces 
not mentioned will get assigned a period, and you will not be able to distinguish 
them in FENs. You can also explicitly assign pieces a period, in which case they 
will not be counted in deciding which captured pieces can go into the holdings.
A tilde '~' as a piece name does mean this piece is used to represent a promoted 
Pawn in crazyhouse-like games, i.e. on capture it turns back onto a Pawn. 
A '+' similarly indicates the piece is a shogi-style promoted piece, that should 
revert to its non-promoted version on capture (rather than to a Pawn).
Note that promoted pieces are represented by pieces 11 further in the list.
You should not have to use this option often: each variant has its own default 
setting for the piece representation in FEN, which should be sufficient in normal use.
Default: ""
@item -debug/-xdebug or -debugMode true/false
@cindex debug, option
@cindex debugMode, option
Turns on debugging printout.
@item -debugFile filename or -nameOfDebugFile filename
@cindex debugFile, option
@cindex nameOfDebugFile, option
Sets the name of the file to which XBoard saves debug information 
(including all communication to and from the engines).
@item -engineDebugOutput number
@cindex engineDebugOutput, option
Specifies how XBoard should handle unsolicited output from the engine, 
with respect to saving it in the debug file. 
The output is further (hopefully) ignored. 
If number=0, XBoard refrains from writing such spurious output to the debug file. 
If number=1, all engine output is written faithfully to the debug file. 
If number=2, any protocol-violating line is prefixed with a '#' character, 
as the engine itself should have done if it wanted to submit info for inclusion in the debug file.
This option is provided for the benefit of applications that use the debug file 
as a source of information, such as the broadcaster of live games TLCV / TLCS. 
Such applications can be protected from spurious engine output that might otherwise confuse them.
@item -rsh or -remoteShell shell-name
@cindex rsh, option
@cindex remoteShell, option
Name of the command used to run programs remotely. The default
is @file{rsh} or @file{remsh}, determined when XBoard is
configured and compiled.
@item -ruser or -remoteUser user-name
@cindex ruser, option
@cindex remoteUser, option
User name on the remote system when running programs with the
@code{remoteShell}. The default is your local user name.
@item -userName username
@cindex userName, option
Name under which the Human player will be listed in the PGN file. 
Default is the login name on your local computer.
@item -delayBeforeQuit number
@itemx -delayAfterQuit number
@cindex delayBeforeQuit, option
@cindex delayAfterQuit, option
These options specify how long XBoard has to wait before sending a termination signal to rogue engine processes, that do not want to react to the 'quit' command. The second one determines the pause after killing the engine, to make sure it dies.

@end table

@node Chess Servers
@chapter Chess Servers
@cindex ICS
@cindex ICS, addresses
@cindex Internet Chess Server
An @dfn{Internet Chess Server}, or @dfn{ICS}, is a place on the
Internet where people can get together to play chess, watch other
people's games, or just chat.  You can use either @code{telnet} or a
client program like XBoard to connect to the server.  There are
thousands of registered users on the different ICS hosts, and it is
not unusual to meet 200 on both chessclub.com and freechess.org.

Most people can just type @kbd{xboard -ics} to start XBoard as an ICS
client.  Invoking XBoard in this way connects you to the Internet
Chess Club (ICC), a commercial ICS.  You can log in there as a guest
even if you do not have a paid account.  To connect to the largest
Free ICS (FICS), use the command @kbd{xboard -ics -icshost freechess.org}
instead, or substitute a different host name to connect to your
favorite ICS.
For a full description of command-line options that control 
the connection to ICS and change the default values of ICS options, see
@ref{ICS options}.  

While you are running XBoard as an ICS client,
you use the terminal window that you started XBoard from
as a place to type in commands and read information that is
not available on the chessboard.

The first time you need to use the terminal is to enter your login name
and password, if you are a registered player. (You don't need to do
this manually; the @code{icsLogon} option can do it for you.
@pxref{ICS options}.)  If you are not registered, 
enter @kbd{g} as your name, and the server will pick a
unique guest name for you.

Some useful ICS commands
include
@table @kbd
@item help <topic>
@cindex help, ICS command
to get help on the given <topic>. To get a list of possible topics type
@dfn{help} without topic.  Try the help command before you ask other
people on the server for help.

For example @kbd{help register} tells you how to become a registered
ICS player.
@item who <flags>
@cindex who, ICS command
to see a list of people who are logged on.  Administrators
(people you should talk to if you have a problem) are marked
with the character @samp{*}, an asterisk. The <flags> allow you to
display only selected players: For example, @kbd{who of} shows a
list of players who are interested in playing but do not have
an opponent.
@item games
@cindex games, ICS command
to see what games are being played
@item match <player> [<mins>] [<inc>]
to challenge another player to a game. Both opponents get <mins> minutes
for the game, and <inc> seconds will be added after each move.
If another player challenges you, the server asks if you want to
accept the challenge; use the @kbd{accept} or @kbd{decline} commands
to answer.
@item accept
@itemx decline
@cindex accept, ICS command
@cindex decline, ICS command
to accept or decline another player's offer. 
The offer may be to start a new game, or to agree to a 
@kbd{draw}, @kbd{adjourn} or @kbd{abort} the current game. @xref{Action Menu}.

If you have more than one pending offer (for example, if more than one player
is challenging you, or if your opponent offers both a draw and to adjourn the
game), you have to supply additional information, by typing something
like @kbd{accept <player>}, @kbd{accept draw}, or @kbd{draw}.
@item draw
@itemx adjourn
@itemx abort
@cindex draw, ICS command
@cindex adjourn, ICS command
@cindex abort, ICS command
asks your opponent to terminate a game by mutual agreement. Adjourned
games can be continued later. 
Your opponent can either @kbd{decline} your offer or accept it (by typing the
same command or typing @kbd{accept}).  In some cases these commands work
immediately, without asking your opponent to agree.  For example, you can
abort the game unilaterally if your opponent is out of time, and you can claim
a draw by repetition or the 50-move rule if available simply by typing 
@kbd{draw}.
@item finger <player>
@cindex finger, ICS command
to get information about the given <player>. (Default: yourself.)
@item vars
@cindex vars, ICS command
to get a list of personal settings
@item set <var> <value>
@cindex set, ICS command
to modify these settings
@item observe <player>
@cindex observe, ICS command
to observe an ongoing game of the given <player>.
@item examine
@itemx oldmoves
@cindex examine, ICS command
@cindex oldmoves, ICS command
to review a recently completed game
@end table

Some special XBoard features are activated when you are
in examine mode on ICS.  See the descriptions of the menu commands
@samp{Forward}, @samp{Backward}, @samp{Pause}, @samp{ICS Client}, 
and @samp{Stop Examining} on the @ref{Step Menu}, @ref{Mode Menu}, and
@ref{Options Menu}.

@node Firewalls
@chapter Firewalls
By default, XBoard communicates with an Internet Chess Server
by opening a TCP socket directly from the machine it is running on
to the ICS. If there is a firewall between your machine and the ICS,
this won't work. Here are some recipes for getting around common
kinds of firewalls using special options to XBoard.
Important: See the paragraph in the below about extra echoes, in
@ref{Limitations}.

Suppose that you can't telnet directly to ICS, but you can telnet
to a firewall host, log in, and then telnet from there to ICS.
Let's say the firewall is called @samp{firewall.example.com}. Set
command-line options as follows:

@example
xboard -ics -icshost firewall.example.com -icsport 23
@end example
@noindent
Or in your @file{.Xresources} file:

@example
XBoard*internetChessServerHost: firewall.example.com
XBoard*internetChessServerPort: 23
@end example
@noindent
Then when you run XBoard in ICS mode, you will be prompted
to log in to the firewall host. This works because port 23 is the
standard telnet login service. Do so, then telnet to ICS, using a
command like @samp{telnet chessclub.com 5000}, or whatever command
the firewall provides for telnetting to port 5000.

If your firewall lets you telnet (or rlogin) to remote hosts but
doesn't let you telnet to port 5000, you may be able to connect to the
chess server on port 23 instead, which is the port the telnet program
uses by default.  Some chess servers support this (including
chessclub.com and freechess.org), while some do not.

If your chess server does not allow connections on port 23 and your
firewall does not allow you to connect to other ports, you may be able
to connect by hopping through another host outside the firewall that
you have an account on.  For instance, suppose you have a shell
account at @samp{foo.edu}. Follow the recipe above, but instead of
typing @samp{telnet chessclub.com 5000} to the firewall, type
@samp{telnet foo.edu} (or @samp{rlogin foo.edu}), log in there, and
then type @samp{telnet chessclub.com 5000}.

Suppose that you can't telnet directly to ICS, but you can use rsh
to run programs on a firewall host, and that host can telnet to ICS.
Let's say the firewall is called @samp{rsh.example.com}. Set
command-line options as follows:

@example
xboard -ics -gateway rsh.example.com -icshost chessclub.com
@end example

@noindent
Or in your @file{.Xresources} file:

@example
XBoard*gateway: rsh.example.com
XBoard*internetChessServerHost: chessclub.com
@end example

Then when you run XBoard in ICS mode, it will connect to
the ICS by using @file{rsh} to run the command
@samp{telnet chessclub.com 5000} on host @samp{rsh.example.com}.

Suppose that you can telnet anywhere you want, but you have to
run a special program called @file{ptelnet} to do so.

First, we'll consider the easy case, in which
@samp{ptelnet chessclub.com 5000} gets you to the chess server.
In this case set command line options as follows:

@example
xboard -ics -telnet -telnetProgram ptelnet
@end example

@noindent
Or in your @file{.Xresources} file:

@example
XBoard*useTelnet: true
XBoard*telnetProgram: ptelnet
@end example

@noindent
Then when you run XBoard in ICS mode, it will issue the
command @samp{ptelnet chessclub.com 5000} to connect to the ICS.

Next, suppose that @samp{ptelnet chessclub.com 5000} doesn't work;
that is, your @file{ptelnet} program doesn't let you connect to
alternative ports. As noted above, your chess server may allow you to
connect on port 23 instead.  In that case, just add the option
@samp{-icsport ""} to the above command, or add
@samp{XBoard*internetChessServerPort:} to your @file{.Xresources} file.
But if your chess server doesn't let you connect on port 23, you will have
to find some other host outside the firewall and hop through it. For
instance, suppose you have a shell account at @samp{foo.edu}. Set
command line options as follows:

@example
xboard -ics -telnet -telnetProgram ptelnet -icshost foo.edu -icsport ""
@end example

@noindent
Or in your @file{.Xresources} file:

@example
XBoard*useTelnet: true
XBoard*telnetProgram: ptelnet
XBoard*internetChessServerHost: foo.edu
XBoard*internetChessServerPort:
@end example

@noindent
Then when you run XBoard in ICS mode, it will issue the
command @samp{ptelnet foo.edu} to connect to your account at
@samp{foo.edu}. Log in there, then type @samp{telnet chessclub.com 5000}.

ICC timestamp and FICS timeseal do not work through some
firewalls.  You can use them only if your firewall gives a clean TCP
connection with a full 8-bit wide path.  If your firewall allows you
to get out only by running a special telnet program, you can't use
timestamp or timeseal across it.  But if you have access to a
computer just outside your firewall, and you have much lower netlag
when talking to that computer than to the ICS, it might be worthwhile
running timestamp there.  Follow the instructions above for hopping
through a host outside the firewall (foo.edu in the example),
but run timestamp or timeseal on that host instead of telnet.

Suppose that you have a SOCKS firewall that will give you a clean
8-bit wide TCP connection to the chess server, but only after you
authenticate yourself via the SOCKS protocol.  In that case, you could
make a socksified version of XBoard and run that.  If you are using
timestamp or timeseal, you will to socksify it, not XBoard; this may
be difficult seeing that ICC and FICS do not provide source code for
these programs.  Socksification is beyond the scope of this document,
but see the SOCKS Web site at http://www.socks.permeo.com/.
If you are missing SOCKS, try http://www.funbureau.com/.

@node Environment
@chapter Environment variables
@cindex Environment variables
@cindex CHESSDIR
Game and position files are found in a directory named by the
@code{CHESSDIR} environment variable. If this variable is not set, the
current working directory is used. If @code{CHESSDIR} is set,
XBoard actually changes its working directory to
@code{$CHESSDIR}, so any files written by the chess engine
will be placed there too.

@node Limitations
@chapter Limitations and known bugs
@cindex Limitations
@cindex Bugs
There is no way for two people running copies of XBoard to play
each other without going through an Internet Chess Server.

Under some circumstances, your ICS password may be echoed when you log on.

If you are connecting to the ICS by running telnet on an Internet
provider or firewall host, you may find that each line you type is
echoed back an extra time after you hit @key{Enter}. If your Internet
provider is a Unix system, you can probably turn its echo off by
typing @kbd{stty -echo} after you log in, and/or typing
@key{^E}@key{Enter} (Ctrl+E followed by the Enter key) to the telnet
program after you have logged into ICS.  It is a good idea to do this
if you can, because the extra echo can occasionally confuse XBoard's
parsing routines.

The game parser recognizes only algebraic notation.

Many of the following points used to be limitations in XBoard 4.2.7 and earlier, 
but are now fixed:
The internal move legality tester in XBoard 4.3.xx does look at the game history, 
and is fully aware of castling or en-passant-capture rights. It permits castling with 
the king on the d file because this is possible in some "wild 1" games on ICS. 
The piece-drop menu does not check piece drops in bughouse to see if you actually hold 
the piece you are trying to drop. But this way of dropping pieces should be considered 
an obsolete feature, now that pieces can be dropped by dragging them from the holdings 
to the board. Anyway, if you would attempt an illegal move when using a chess engine or the ICS, 
XBoard will accept the error message that comes back, undo the move, and let you try another.
FEN positions saved by XBoard do include correct information about whether castling or 
en passant are legal, and also handle the 50-move counter.
The mate detector does not understand that non-contact mate is not really mate in bughouse. 
The only problem this causes while playing is minor: a "#" (mate indicator) character will 
show up after a non-contact mating move in the move list. XBoard will not assume the game 
is over at that point, not even when the option Detect Mates is on.
Edit Game mode always uses the rules of the selected variant, 
which can be a variant that uses piece drops.  
You can load and edit games that contain piece drops. 
The (obsolete) piece menus are not active, 
but you can perform piece drops by dragging pieces from the holdings.
Edit Position mode does not allow you to edit the crazyhouse holdings properly. 
You cannot drag pieces to the holding, and using the popup menu to put pieces 
there does not adapt the holding counts and leads to an inconsistent state. 
Set up crazyhouse positions by loading / pasting a bFEN, from there you can set the holdings.
Fischer Random castling is fully understood. 
You can enter castlings by dragging the King on top of your Rook. 
You can probably also play Fischer Random successfully on ICS by typing 
castling moves into the ICS Interaction window.

The menus may not work if your keyboard is in Caps Lock or Num Lock mode.
This seems to be a problem with the Athena menu widget,
not an XBoard bug.

Also see the ToDo file included with the distribution for many other
possible bugs, limitations, and ideas for improvement that have been
suggested.
@node Problems
@chapter Reporting problems
@cindex Bugs
@cindex Bug reports
@cindex Reporting bugs
@cindex Problems
@cindex Reporting problems

You can report bugs and problems with XBoard using
the bug tracker at @code{https://savannah.gnu.org/projects/xboard/}
or by sending mail to @code{<bug-xboard@@gnu.org>}.  It can also
be useful to report or discuss bugs in the WinBoard Forum at
@code{http://www.open-aurec.com/wbforum/}, 
WinBoard development section.

Please use the @file{script} program to start a typescript, run 
XBoard with the @samp{-debug} option, and include the typescript
output in your message.
Also tell us what kind of machine and what operating system version
you are using.  The command @samp{uname -a} will often tell you this.

If you improve XBoard, please send a message about your changes,
and we will get in touch with you about merging them in
to the main line of development.

@node Contributors
@chapter Authors and contributors
@cindex Authors
@cindex Contributors

Chris Sears and Dan Sears wrote the original XBoard.  They were
responsible for versions 1.0 through 1.2.  The color scheme was taken
from Wayne Christopher's @code{XChess} program.

Tim Mann was primarily responsible for XBoard versions 1.3 through
4.2.7, and for WinBoard (a port of XBoard to Microsoft Win32) from its
inception through version 4.2.7.

John Chanak contributed the initial implementation of ICS mode.  Evan
Welsh wrote @code{CMail}, and Patrick Surry helped in designing,
testing, and documenting it.  Elmar Bartel contributed the new piece
bitmaps introduced in version 3.2.  Jochen Wiedmann converted the
documentation to texinfo.  Frank McIngvale added click/click moving,
the Analysis modes, piece flashing, ZIICS import, and ICS text
colorization to XBoard.  Hugh Fisher added animated piece movement to
XBoard, and Henrik Gram added it to WinBoard.  Mark Williams
contributed the initial (WinBoard-only) implementation of many new
features added to both XBoard and WinBoard in version 4.1.0, including
copy/paste, premove, icsAlarm, autoFlipView, training mode, auto
raise, and blindfold.  Ben Nye contributed X copy/paste code for
XBoard.

In a fork from version 4.2.7, Alessandro Scotti added many elements to
the user interface of WinBoard, including the board textures and
font-based rendering, the evaluation-graph, move-history and
engine-output window.  He was also responsible for adding the UCI
support.

H. G. Muller continued this fork of the project, producing version
4.3.  He made WinBoard castling- and e.p.-aware, added variant support
with adjustable board sizes, the crazyhouse holdings, and the fairy
pieces.  In addition he added most of the adjudication options, made
WinBoard more robust in dealing with buggy and crashing engines, and
extended time control with a time-odds and node-count-based modes.
Most of the options that initially were WinBoard only have now been
back-ported to XBoard.

Michel van den Bergh provided the code for reading Polyglot opening books.

Meanwhile, some work continued on the GNU XBoard project maintained at
savannah.gnu.org, but version 4.2.8 was never released.  Daniel
Mehrmann was responsible for much of this work.

Most recently, Arun Persaud worked with H. G. Muller to merge all
the features of the never-released XBoard/WinBoard 4.2.8 of the GNU
XBoard project and the never-released 4.3.16 from H. G.'s fork into a
unified XBoard/WinBoard 4.4, which is now available both from the
savannah.gnu.org web site and the WinBoard forum.

@node CMail
@chapter CMail
@cindex cmail
The @file{cmail} program can help you play chess by email with opponents of
your choice using XBoard as an interface.

You will usually run @file{cmail} without giving any options.

@menu
* CMail options::    Invoking CMail.
* CMail game::       Starting a CMail game.
* CMail answer::     Answering a move.
* CMail multi::      Multiple games in one message.
* CMail completion:: Completing a game.
* CMail trouble::    Known CMail problems.
@end menu

@node CMail options
@section CMail options
@table @asis
@item -h
Displays @file{cmail} usage information.
@item -c
Shows the conditions of the GNU General Public License.
@xref{Copying}.
@item -w
Shows the warranty notice of the GNU General Public License.
@xref{Copying}.
@item -v
@itemx -xv
Provides or inhibits verbose output from @file{cmail} and XBoard,
useful for debugging. The
@code{-xv}
form also inhibits the cmail introduction message.
@item -mail
@itemx -xmail
Invokes or inhibits the sending of a mail message containing the move.
@item -xboard
@itemx -xxboard
Invokes or inhibits the running of XBoard on the game file.
@item -reuse
@itemx -xreuse
Invokes or inhibits the reuse of an existing XBoard to display the
current game.
@item -remail
Resends the last mail message for that game. This inhibits running
XBoard.
@item -game <name>
The name of the game to be processed.
@item -wgames <number>
@itemx -bgames <number>
@itemx -games <number>
Number of games to start as White, as Black or in total. Default is 1 as
white and none as black. If only one color is specified then none of the
other color is assumed. If no color is specified then equal numbers of
White and Black games are started, with the extra game being as White if an
odd number of total games is specified.
@item -me <short name>
@itemx -opp <short name>
A one-word alias for yourself or your opponent.
@item -wname <full name>
@itemx -bname <full name>
@itemx -name <full name>
@itemx -oppname <full name>
The full name of White, Black, yourself or your opponent.
@item -wna <net address>
@itemx -bna <net address>
@itemx -na <net address>
@itemx -oppna <net address>
The email address of White, Black, yourself or your opponent.
@item -dir <directory>
The directory in which @file{cmail} keeps its files. This defaults to the
environment variable @code{$CMAIL_DIR} or failing that, @code{$CHESSDIR},
@file{$HOME/Chess} or @file{~/Chess}. It will be created if it does not exist.
@item -arcdir <directory>
The directory in which @file{cmail} archives completed games. Defaults to
the environment variable @code{$CMAIL_ARCDIR} or, in its absence, the same
directory as cmail keeps its working files (above).
@item -mailprog <mail program>
The program used by cmail to send email messages. This defaults to the
environment variable @code{$CMAIL_MAILPROG} or failing that
@file{/usr/ucb/Mail}, @file{/usr/ucb/mail} or @file{Mail}. You will need
to set this variable if none of the above paths fit your system.
@item -logFile <file>
A file in which to dump verbose debugging messages that are invoked with
the @samp{-v}
option.
@item -event <event>
The PGN Event tag (default @samp{Email correspondence game}).
@item -site <site>
The PGN Site tag (default @samp{NET}).
@item -round <round>
The PGN Round tag (default @samp{-}, not applicable).
@item -mode <mode>
The PGN Mode tag (default @samp{EM}, Electronic Mail).
@item Other options
Any option flags not listed above are passed through to XBoard.
Invoking XBoard through CMail changes the default values of two XBoard
options: The default value for @samp{-noChessProgram} is changed to
true; that is, by default no chess engine is started.  The default
value for @samp{-timeDelay} is changed to 0; that is, by default
XBoard immediately goes to the end of the game as played so far,
rather than stepping through the moves one by one.  You can still set
these options to whatever values you prefer by supplying them on
CMail's command line.  @xref{Options}.
@end table

@node CMail game
@section Starting a CMail Game
Type @file{cmail} from a shell to start a game as white. After an opening
message, you will be prompted for a game name, which is optional---if you
simply press @key{Enter}, the game name will take the form
@samp{you-VS-opponent}. You will next be prompted for the short name
of your opponent. If you haven't played this person before, you will also
be prompted for his/her email address. @file{cmail} will then invoke
XBoard in the background. Make your first move and select
@samp{Mail Move} from the @samp{File} menu. @xref{File Menu}. If all is well,
@file{cmail} will mail a copy of the move to your opponent. If you select
@samp{Exit} without having selected @samp{Mail Move} then no move will be
made.

@node CMail answer
@section Answering a Move
When you receive a message from an opponent containing a move in one of
your games, simply pipe the message through @file{cmail}. In some mailers
this is as simple as typing @kbd{| cmail} when viewing the message, while in
others you may have to save the message to a file and do @kbd{cmail < file}
at the command line. In either case @file{cmail} will display the game using
XBoard. If you didn't exit XBoard when you made your first move
then @file{cmail} will do its best to use the existing XBoard instead
of starting a new one. As before, simply make a move and select
@samp{Mail Move} from the @samp{File} menu. @xref{File Menu}. @file{cmail}
will try to use the
XBoard that was most recently used to display the current game. This
means that many games can be in progress simultaneously, each with its own
active XBoard.

If you want to look at the history or explore a variation, go ahead, but
you must return to the current position before XBoard will allow you
to mail a move. If you edit the game's history you must select
@samp{Reload Same Game} from the @samp{File} menu to get back to the original
position, then make the move you want and select @samp{Mail Move}.
As before, if you decide you aren't ready to make a move just yet you can
either select @samp{Exit} without sending a move or just leave
XBoard running until you are ready.

@node CMail multi
@section Multi-Game Messages

It is possible to have a @file{cmail} message carry more than one game.
This feature was implemented to handle IECG (International Email Chess
Group) matches, where a match consists of one game as white and one as black,
with moves transmitted simultaneously. In case there are more general uses,
@file{cmail} itself places no limit on the number of black/white games
contained in a message; however, XBoard does.

@node CMail completion
@section Completing a Game
Because XBoard can detect checkmate and stalemate, @file{cmail}
handles game termination sensibly. As well as resignation, the
@samp{Action} menu allows draws to be offered and accepted for
@file{cmail} games.

For multi-game messages, only unfinished and just-finished games will be
included in email messages. When all the games are finished, they are
archived in the user's archive directory, and similarly in the opponent's
when he or she pipes the final message through @file{cmail}. The archive
file name includes the date the game was started.

@node CMail trouble
@section Known CMail Problems
It's possible that a strange conjunction of conditions may occasionally
mean that @file{cmail} has trouble reactivating an existing
XBoard. If this should happen, simply trying it again should work.
If not, remove the file that stores the XBoard's PID
(@file{game.pid}) or use the @samp{-xreuse} option to force
@file{cmail} to start a new XBoard.

Versions of @file{cmail} after 2.16 no longer understand the old file format
that XBoard used to use and so cannot be used to correspond with
anyone using an older version.

Versions of @file{cmail} older than 2.11 do not handle multi-game messages,
so multi-game correspondence is not possible with opponents using an older
version.

@node Other programs
@chapter Other programs you can use with XBoard
@cindex Other programs

Here are some other programs you can use with XBoard

@menu
* GNU Chess::        The GNU Chess engine.
* Fairy-Max::        The Fairy-Max chess engine.
* HoiChess::         The HoiChess chess engine.
* Crafty::           The Crafty chess engine.
* zic2xpm::          The program used to import chess sets from ZIICS.
@end menu

@node GNU Chess
@section GNU Chess

The GNU Chess engine is available from:

ftp://ftp.gnu.org/gnu/gnuchess/

You can use XBoard to play a game against GNU Chess, or to
interface GNU Chess to an ICS.

@node Fairy-Max
@section Fairy-Max

Fairy-Max is a derivative from the once World's smallest Chess program micro-Max,
which measures only about 100 lines of source code.
The main difference with micro-Max is that Fairy-Max loads its move-generator
tables from a file, so that the rules for piece movement can be easily configured
to implement unorthodox pieces.
Fairy-Max can therefore play a large number of variants, normal Chess being one of those.
In addition it plays Knightmate, Capablanca and Gothic Chess, Shatranj, Courier Chess,
Cylinder chess, Berolina Chess, while the user can easily define new variants.
It can be obtained from:

http://home.hccnet.nl/h.g.muller/dwnldpage.html

@node HoiChess
@section HoiChess

HoiChess is a not-so-very-strong Chess engine, which comes with a derivative HoiXiangqi,
able to play Chinese Chess. It can be obtained from the standard Linux repositories
through:

sudo apt-get install hoichess

@node Crafty
@section Crafty

Crafty is a chess engine written by Bob Hyatt.
You can use XBoard to play a game against Crafty, hook Crafty up
to an ICS, or use Crafty to interactively analyze games and positions
for you.

Crafty is a strong, rapidly evolving chess program. This rapid
pace of development is good, because it means Crafty is always
getting better.  This can sometimes cause problems with
backwards compatibility, but usually the latest version of Crafty
will work well with the latest version of XBoard.
Crafty can be obtained from its author's FTP site:
ftp://ftp.cis.uab.edu/hyatt/.

To use Crafty with XBoard, give the -fcp and -fd options as follows, where
<crafty's directory> is the directory in which you installed Crafty
and placed its book and other support files.

@node zic2xpm
@section zic2xpm

The ``zic2xpm'' program is used to import chess sets from the ZIICS(*)
program into XBoard. ``zic2xpm'' is part of the XBoard distribution.
ZIICS is available from:

ftp://ftp.freechess.org/pub/chess/DOS/ziics131.exe

To import ZIICS pieces, do this:
@table @asis
@item 1. Unzip ziics131.exe into a directory:

@example
unzip -L ziics131.exe -d ~/ziics
@end example
@item 2. Use zic2xpm to convert a set of pieces to XBoard format.

For example, let's say you want to use the
FRITZ4 set. These files are named ``fritz4.*'' in the ZIICS distribution.

@example
mkdir ~/fritz4
cd ~/fritz4
zic2xpm ~/ziics/fritz4.*
@end example
@item 3. Give XBoard the ``-pixmap'' option when starting up, e.g.:

@example
xboard -pixmap ~/fritz4
@end example

Alternatively, you can add this line to your @file{.Xresources} file:

@example
xboard*pixmapDirectory: ~/fritz4
@end example
@end table

(*) ZIICS is a separate copyrighted work of Andy McFarland.
The ``ZIICS pieces'' are copyrighted works of their respective
creators. Files produced by ``zic2xpm'' are for PERSONAL USE ONLY
and may NOT be redistributed without explicit permission from
the original creator(s) of the pieces.

@ifnottex
@node Copyright
@unnumbered Copyright
@include copyright.texi
@end ifnottex

@node Copying
@unnumbered GNU GENERAL PUBLIC LICENSE
@include gpl.texinfo

@c noman
@node Index
@unnumbered Index

@printindex cp
@contents
@c end noman

@bye