[gnushogi.git] / doc / gnushogi.texinfo

\input texinfo   @c -*-texinfo-*-

@c % **  Start of header.
@setfilename gnushogi.info
@settitle GNU Shogi manual
@c % **  End of header.

@dircategory Games
@direntry
* gnushogi: (gnushogi).          Japanese chess
@end direntry

@setchapternewpage odd

@c ==================================
@c TeX-specific macros
@c ==================================

@c None yet!

@c ==================================
@c info-specific macros
@c ==================================

@c None yet!

@c ==================================
@c Summary description and copyright.
@c ==================================

@ifinfo

This file describes how to use GNU shogi, 
a program which plays Shogi (Japanese chess).

Copyright (C) 1999 Michael C. Vanier and the Free Software Foundation, Inc.

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

@ignore
Permission is granted to process this file through TeX and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).
@end ignore

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation approved
by the Free Software Foundation.

@end ifinfo

@c =========================================
@c End of summary description and copyright.
@c =========================================


@c ====================
@c Title and copyright.
@c ====================

@titlepage
@sp 10
@comment The title is printed in a large font.
@center @titlefont{GNU Shogi (Japanese chess)}
@author   Mike Vanier

@c  The following two commands start the copyright page.
@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1999 Michael C. Vanier and the Free Software Foundation

@end titlepage

@c ===========================
@c End of title and copyright.
@c ===========================


@c =========================
@c Top node and master menu.
@c =========================

@node    Top, (dir), (dir), (dir)
@top     GNU Shogi (Japanese chess)

@ifinfo
@menu
* Introduction::         What is GNU shogi?
* License::              The GNU General Public License.
* About shogi::          General information, rules, etc.
* gnushogi::             How to play GNU shogi (gnushogi).
* xshogi::               The X interface to GNU shogi.
* References and links:: Where to go for more information.
* Acknowledgements::
* Bugs::                 Where and how to report bugs.
* Index::        
@end menu
@end ifinfo

@iftex
This document describes GNU shogi, a program which plays Japanese chess
(shogi) against a human opponent.
@end iftex

@c ================================
@c End of top node and master menu.
@c ================================


@c =====
@c Body.
@c =====

@node Introduction, License, Top, Top
@chapter Introduction
@cindex Introduction

GNU shogi is a program that plays shogi, the Japanese version of chess,
against a human (or computer) opponent.  This file describes how to use
GNU shogi and also gives background information about the game of shogi.

This file describes GNU shogi version 1.3.2.  It was written by me, Mike
Vanier, the current maintainer of GNU shogi.  My email address is
@email{mvanier@@cs.caltech.edu}.


GNU shogi is actually two programs: 

@sp 1

@table @samp

@item gnushogi
is the text-based program which also contains the game-playing engine.

@item xshogi
is the X-windows graphical interface to gnushogi.

@end table

@sp 1

Since xshogi invokes gnushogi, most players will just type ``xshogi''
and start playing.

Disclaimer: I use the personal pronouns ``him'', ``his'' etc. to refer
to a shogi player regardless of gender.  That's easier than writing
``his or her'' all over the place.  I don't mean to infer that women
don't play shogi; in fact shogi is very popular in Japan among women as
well as men.



@node License, About shogi, Introduction, Top
@unnumbered GNU GENERAL PUBLIC LICENSE
@cindex License
@cindex GPL
@center Version 2, June 1991

@display
Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
@end display

@unnumberedsec Preamble

  The licenses for most software are designed to take away your
freedom to share and change it.  By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software---to make sure the software is free for all its users.  This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it.  (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.)  You can apply it to
your programs, too.

  When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.

  To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.

  For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have.  You must make sure that they, too, receive or can get the
source code.  And you must show them these terms so they know their
rights.

  We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.

  Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software.  If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.

  Finally, any free program is threatened constantly by software
patents.  We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary.  To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.

  The precise terms and conditions for copying, distribution and
modification follow.

@page
@iftex
@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
@end iftex
@ifinfo
@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
@end ifinfo

@enumerate 0
@item
This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License.  The ``Program'', below,
refers to any such program or work, and a ``work based on the Program''
means either the Program or any derivative work under copyright law:
that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another
language.  (Hereinafter, translation is included without limitation in
the term ``modification''.)  Each licensee is addressed as ``you''.

Activities other than copying, distribution and modification are not
covered by this License; they are outside its scope.  The act of
running the Program is not restricted, and the output from the Program
is covered only if its contents constitute a work based on the
Program (independent of having been made by running the Program).
Whether that is true depends on what the Program does.

@item
You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty;
and give any other recipients of the Program a copy of this License
along with the Program.

You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.

@item
You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:

@enumerate a
@item
You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.

@item
You must cause any work that you distribute or publish, that in
whole or in part contains or is derived from the Program or any
part thereof, to be licensed as a whole at no charge to all third
parties under the terms of this License.

@item
If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display an
announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
these conditions, and telling the user how to view a copy of this
License.  (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
@end enumerate

These requirements apply to the modified work as a whole.  If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works.  But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
exercise the right to control the distribution of derivative or
collective works based on the Program.

In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
the scope of this License.

@item
You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:

@enumerate a
@item
Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections
1 and 2 above on a medium customarily used for software interchange; or,

@item
Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; or,

@item
Accompany it with the information you received as to the offer
to distribute corresponding source code.  (This alternative is
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with such
an offer, in accord with Subsection b above.)
@end enumerate

The source code for a work means the preferred form of the work for
making modifications to it.  For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable.  However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.

If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.

@item
You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.

@item
You are not required to accept this License, since you have not
signed it.  However, nothing else grants you permission to modify or
distribute the Program or its derivative works.  These actions are
prohibited by law if you do not accept this License.  Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.

@item
Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions.  You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.

@item
If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent issues),
conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License.  If you cannot
distribute so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you
may not distribute the Program at all.  For example, if a patent
license would not permit royalty-free redistribution of the Program by
all those who receive copies directly or indirectly through you, then
the only way you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.

It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices.  Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.

This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.

@item
If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded.  In such case, this License incorporates
the limitation as if written in the body of this License.

@item
The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

Each version is given a distinguishing version number.  If the Program
specifies a version number of this License which applies to it and ``any
later version'', you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation.  If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.

@item
If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission.  For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this.  Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.

@page
@iftex
@heading NO WARRANTY
@end iftex
@ifinfo
@center NO WARRANTY
@end ifinfo

@item
BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

@item
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.
@end enumerate

@iftex
@heading END OF TERMS AND CONDITIONS
@end iftex
@ifinfo
@center END OF TERMS AND CONDITIONS
@end ifinfo

@page
@unnumberedsec How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the ``copyright'' line and a pointer to where the full notice is found.

@smallexample
@var{one line to give the program's name and a brief idea of what it does.}
Copyright (C) 19@var{yy}  @var{name of author}

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
@end smallexample

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

@smallexample
Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author}
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details 
type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
@end smallexample

The hypothetical commands @samp{show w} and @samp{show c} should show
the appropriate parts of the General Public License.  Of course, the
commands you use may be called something other than @samp{show w} and
@samp{show c}; they could even be mouse-clicks or menu items---whatever
suits your program.

You should also get your employer (if you work as a programmer) or your
school, if any, to sign a ``copyright disclaimer'' for the program, if
necessary.  Here is a sample; alter the names:

@smallexample
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.

@var{signature of Ty Coon}, 1 April 1989
Ty Coon, President of Vice
@end smallexample

This General Public License does not permit incorporating your program into
proprietary programs.  If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library.  If this is what you want to do, use the GNU Library General
Public License instead of this License.


@node    About shogi, gnushogi, License, Top
@chapter About the game of shogi
     

@quotation
``Japanese chess cedes nothing in depth or beauty to the European
game... it is at least as interesting.''

--- Alexander Alekhine @*
(quoted in David Pritchard, @cite{The Encyclopedia of Chess Variants}) 

@sp 1

``... shogi [is] by far the most complex form of chess that has ever
achieved widespread popularity.''

--- R. Wayne Schmittberger, @cite{New Rules for Classic Games}
@end quotation

@sp 1

Shogi is the version of chess played in Japan.  It is strikingly
different from standard chess (which I shall refer to henceforth as
``international chess'') and also to all other regional variants,
because captured pieces can re-enter play on the side of the capturer.
This has several interesting effects on the play of the game:

@sp 1

@enumerate
@item
Shogi is much more complex than international chess, at least in
terms of the average number of possible moves per turn (estimated at
about 35 for chess and at about 80 for shogi).

@item
There are almost no draws (about 1-2% of all games in professional play).

@item
Exchanges complicate the play rather than simplifying it.

@item
There are no ``endgames'' in the standard chess sense; all pieces remain
in play throughout the game.  Games typically end in a race to
checkmate the other player before being checkmated oneself.

@item
Ownership of a piece is not indicated by the color of the piece;
instead, pieces are wedge-shaped and point towards the opponent.  The
name of the piece is inscribed in Kanji characters on the front of the
piece.

@item
Most importantly: it's more fun than other forms of chess :-)

@end enumerate

@sp 1

Shogi is extremely popular in Japan; it has been estimated that 20
million Japanese can play shogi, of which perhaps 1 million are active
players.  It is even more popular there than the game of go, Japan's
other favorite board game.  There are a number of professional players
who make a considerable amount of money playing in shogi tournaments,
and the game receives extensive newpaper and television coverage.
Despite this, the game has yet to become popular outside of Japan.  Part
of this is because the Kanji characters on the pieces scare away some
people, but mostly it's due, I think, to lack of exposure to the game
and to the difficulty of finding opponents.  I hope that GNU shogi will
help introduce shogi to a wider audience.

@ifinfo
@menu
* The rules of shogi::
* Sample game::
* Mating problems::
* Shogi variants::
* Differences between shogi and chess::
@end menu
@end ifinfo


@c -------------------------------------------------------
@c 
@c The rules of shogi.
@c
@c -------------------------------------------------------

@node    The rules of shogi, Sample game, About shogi, About shogi
@section The rules of shogi
@cindex  Rules

Shogi is a two-person abstract strategy board game with full information
(i.e. all pieces and moves are visible to both players at all times).
It is in the chess family, being descended from the same ancestral game
as international chess: the Indian game of Chaturanga.  The two players
are referred to as ``Black'' and ``White'', with Black moving first
(unlike in international chess, where White moves first), and with
movement alternating between the two players.  Note that ``Black'' and
``White'' are just names; the pieces are not colored.  Instead, they are
flat, wedge-shaped pieces which point towards the opponent.  The
identity of a given piece is indicated by two Japanese Kanji characters
on each piece.  In fact, only the top character is needed to identify
the piece and thus only the top character is used in shogi diagrams.  I
will use alphabetical equivalents in the diagrams here; to see what the
Kanji characters look like, start up xshogi (@pxref{xshogi}) and compare
the starting setup there with the starting setup in this file
(@pxref{The opening setup}).

The object of the game is to capture the opponent's King.  The board is
a grid of 9x9 uncolored squares, and pieces are placed on the squares.
Each player begins with 20 pieces, described in the next section.
Capture is by displacement, as in international chess.

@ifinfo
@menu
* The moves of the pieces::
* The opening setup::
* Promotion of pieces::
* Drops::
* Winning the game::
* Draws::
* Handicaps::
* Notes for chess players::
@end menu
@end ifinfo

@c The moves of the pieces.

@node       The moves of the pieces, The opening setup, The rules of shogi, The rules of shogi
@subsection The moves of the pieces
@cindex     Piece moves

Each player at the beginning of a shogi game has a total of 20 pieces of
eight different types.  The moves of the shogi pieces can be divided
into three classes: ``stepping'' pieces, that only move one square at a
time; ``ranging'' pieces that move any number of unobstructed squares in
a line, and ``jumping'' pieces that can jump over obstructing pieces to
reach their destination squares.  Most pieces can also promote to
different (usually stronger) pieces under certain circumstances (see the
next section).  All pieces capture the same way that they move (even
pawns).  The piece moves and promotions are as follows; each piece name
is followed by the standard piece abbreviation:

@enumerate

@item
The king (K).  The king can move one square in any horizontal, vertical,
or diagonal direction, just like the king in international chess.  The
king does not promote.

@item
The rook (R).  The rook can move any number of squares in a horizontal
or vertical direction.  The rook is the same as the rook in
international chess (except that it can promote).  A rook promotes to a
``dragon king'' or ``dragon'' for short (often just referred to as a
``promoted rook''), which can move as a rook or can move one square in
any diagonal direction.

@item
The bishop (B).  The bishop can move any number of squares in a diagonal
direction.  The bishop is the same as the bishop in international chess
(except that it can promote).  A bishop promotes to a ``dragon horse''
or ``horse'' for short (often just referred to as a ``promoted
bishop''), which can move as a bishop or can move one square in any
horizontal or vertical direction.  Note: the horse should not be
confused with a knight (see below), as they are two completely different
pieces.

@item
The gold general (G).  A gold general can move one square in any
horizontal or vertical direction, or one square in a forward diagonal
direction.  Gold generals do not promote.

@item
The silver general (S).  A silver general can move one square in any
diagonal direction, or one square straight forward.  A silver general
promotes to a gold general.

@item
The knight (N).  A knight can move one square straight forward followed
by one square to either forward diagonal, jumping over intervening
pieces if any.  In other words, a knight moves like its international
chess counterpart, but forward only.  A knight promotes to a gold
general.  The knight is the only jumping piece, as in chess.

@item
The lance (L).  A lance can move any number of squares straight forward.
A lance promotes to a gold general.

@item
The pawn (P).  A pawn can move one square straight forward.  The pawn
captures the same way that it moves, in contrast to international chess.
There is also no initial two-space move for pawns and no
@emph{en-passant} capture.  A pawn promotes to a gold general; a
promoted pawn is usually known as a ``Tokin''.

@end enumerate


@c The opening setup.

@node       The opening setup, Promotion of pieces, The moves of the pieces, The rules of shogi
@subsection The opening setup
@cindex     Opening setup

The opening setup for shogi is as follows:

@ifinfo

   9    8    7    6    5    4    3    2    1
+---------------------------------------------+     @*
| wL | wN | wS | wG | wK | wG | wS | wN | wL |  a   @*  
+---------------------------------------------+     @*  
|    | wR |    |    |    |    |    | wB |    |  b   @*  
+---------------------------------------------+     @*  
| wP | wP | wP | wP | wP | wP | wP | wP | wP |  c   @*
+---------------------------------------------+     @*
|    |    |    |    |    |    |    |    |    |  d   @*
+---------------------------------------------+     @*
|    |    |    |    |    |    |    |    |    |  e   @*
+---------------------------------------------+     @*
|    |    |    |    |    |    |    |    |    |  f   @*
+---------------------------------------------+     @*
| bP | bP | bP | bP | bP | bP | bP | bP | bP |  g   @*
+---------------------------------------------+     @*  
|    | bB |    |    |    |    |    | bR |    |  h   @*
+---------------------------------------------+     @*  
| bL | bN | bS | bG | bK | bG | bS | bN | bL |  i   @* 
+---------------------------------------------+
@end ifinfo

@c The following TeX macros are taken with permission from 
@c "TeX for the Beginner" by Wynter Snow.

@tex
\def\startline{\par\nobreak\noindent}

{\obeylines\obeyspaces%
\gdef\beginVerbatim{\bigbreak%
\begingroup%
\parskip=0pt%
\obeylines\obeyspaces%
\let^^M=\startline%
\tt}}
\gdef\endVerbatim{\endgroup\bigbreak}
\beginVerbatim


   9    8    7    6    5    4    3    2    1
+--------------------------------------------+     
| wL | wN | wS | wG | wK | wG | wS | wN | wL |  a   
+--------------------------------------------+     
|    | wR |    |    |    |    |    | wB |    |  b   
+--------------------------------------------+     
| wP | wP | wP | wP | wP | wP | wP | wP | wP |  c   
+--------------------------------------------+     
|    |    |    |    |    |    |    |    |    |  d   
+--------------------------------------------+     
|    |    |    |    |    |    |    |    |    |  e   
+--------------------------------------------+     
|    |    |    |    |    |    |    |    |    |  f   
+--------------------------------------------+     
| bP | bP | bP | bP | bP | bP | bP | bP | bP |  g   
+--------------------------------------------+     
|    | bB |    |    |    |    |    | bR |    |  h   
+--------------------------------------------+     
| bL | bN | bS | bG | bK | bG | bS | bN | bL |  i   
+--------------------------------------------+

\endVerbatim
@end tex

@sp 1

Here, ``b'' stands for ``black'' and ``w'' stands for ``white'', so
that, for instance, ``bL'' means ``black lance''.  The numbers above the
files and the letters to the right of the ranks represent the most
common notation system used for shogi by westerners (the Japanese also
use Arabic numerals for the files but use Japanese numerals for the
ranks).  


@c Promotion of pieces.

@node       Promotion of pieces, Drops, The opening setup, The rules of shogi
@subsection Promotion of pieces
@cindex     Piece promotion

In sharp contrast to international chess, where only pawns can promote
to higher-ranked pieces, most of the pieces in shogi can promote.  The
promoted ranks are discussed in the section on piece moves (@pxref{The
moves of the pieces}) but are repeated here for reference:

@table @asis

@item Pawn
promotes to gold general (called a `tokin' in this case only).

@item Lance
promotes to gold general.

@item Knight
promotes to gold general.

@item Silver general
promotes to gold general.

@item Gold general
does not promote.

@item Bishop
promotes to ``dragon horse'' or just ``horse'' for short.  The horse can
move as a bishop or can move one square in any orthogonal direction.

@item Rook
promotes to ``dragon king'' or just ``dragon'' for short.  The dragon
can move as a rook or can move one square in any diagonal direction.

@item King
does not promote.

@end table

@sp 1

The three ranks furthest away from each player constitute his/her
``promotion zone''.  A player may, but is not required to, promote a
piece after making a move in which the piece begins and/or ends in the
promotion zone.  Thus you can promote a piece when moving the piece into
the promotion zone, out of the promotion zone, or entirely within the
promotion zone.  Promotion is mandatory in these cases:

@sp 1

@enumerate

@item You must promote a pawn or a lance after moving it to the last rank.

@item You must promote a knight after moving it to either of the last
two ranks.

@end enumerate

@sp 1

These forced promotions ensure that a piece cannot be moved to a square
from which it would have no further move.

Pieces ``dropped'' onto the board (@pxref{Drops}) always drop in the
unpromoted state, even if they drop into the promotion zone.



@c Drops.

@node       Drops, Winning the game, Promotion of pieces, The rules of shogi
@subsection Drops
@cindex     Drops

When a player captures a piece, that piece is not removed from play.
Instead, it becomes the property of the capturer and can re-enter play
by being placed on (almost) any vacant square during the player's move.
This is known as a ``drop'' and counts as a full move (in other words,
you can either move a piece on the board or drop a piece onto the board
during your move, but not both).  All pieces drop in the unpromoted
state.  Pieces may be legally dropped in their promotion zone, but they
do not promote on that turn.

There are several restrictions on drops:

@enumerate

@item A pawn may not be dropped onto a file if there is already an
unpromoted pawn belonging to the same player on that file.  It is legal
to drop a pawn on a file which contains a @emph{promoted} pawn belonging
to the same player, however.

@item A pawn may not be dropped to give immediate checkmate on the
move.  A pawn is, however, permitted to be moved on the board to give
immediate checkmate.  This is a curious rule, and if anyone knows the
reason for it I would appreciate it if they would contact me and explain
it to me :-)

@item A pawn or piece may not be dropped onto a square from which they
would have no legal move.  This means that pawns and lances may not be
dropped onto the last rank, and the knight may not be dropped onto the
last or second-to-last rank.

@end enumerate

It is entirely permissible (and often advisable) to drop a piece or pawn
between one's King and an attacking ranging piece.  For this reason,
the final checkmating move is nearly always an attack on the King from
an adjacent square (except for an attack by a Knight).

Captured pieces are said to be pieces ``in hand''.

The drop is the primary distinguishing feature of Japanese chess, shared
with no other popular chess-type game.  It gives shogi a very aggressive
quality, and dramatically increases the number of possible moves once a
few pieces have been captured.  Another interesting feature of shogi is
that exchanges complicate play rather than simplifying it (as in
international chess), because of the drop rule.


@c Winning.

@node       Winning the game, Draws, Drops, The rules of shogi
@subsection Winning the game
@cindex     Winning the game

A game of shogi is won by capturing the opponent's king.  In general,
this is done by checkmating the king: attacking the king in such a way
that the king cannot be defended no matter what the defending player
moves.  Note, though, that there is no rule that requires a player to
defend a king which is being attacked.  However, if he does not defend
his king, the opponent is entirely free to capture it on the next move,
thus winning the game.  As in international chess, in practice most
games end by resignation when one player realizes that he cannot escape
checkmate. 


@c Draws.

@node       Draws, Handicaps, Winning the game, The rules of shogi
@subsection Draws
@cindex     Draws

There are very few draws in shogi; only about 1-2% of professional games
end in a draw.  One reason for this is that material can never be
depleted as in chess, because captured pieces are constantly re-entering
play as a consequence of the drop rule.  In fact, most of the ways a
game can be drawn in chess are not allowed in shogi:

@sp 1

@itemize @bullet

@item Draws cannot be offered.

@item There is no fifty-move rule.

@item A stalemate counts as a win for the stalemater.  Stated otherwise:
if you can't move, you lose.

@item Perpetual check is illegal (see below).

@end itemize

@sp 1

There are only two legal ways in which a draw can occur:

@sp 1

@enumerate

@item A position (including the pieces in hand) occurs 4 times with the same
player to move (called ``Sennichite'').  However, if this is caused by
consecutive checks (direct attacks on the King, threatening to capture
it on the next move) by one side, the player giving these checks loses
the game.  In other words, perpetual check results in a loss for the
attacker who recreates the same position the 4th time.

@item Both players have moved their King into the the promotion zone (or they
cannot be prevented from doing so) and the Kings cannot be checkmated.
A King who has entered the promotion zone is known as an ``entering
King''; due to the forward orientation of most shogi pieces, it is very
hard to mate such a King.  In that case the players may decide to count
their pieces as follows: the King does not count, the Rook and Bishop
count as 5 points, and all other pieces as one point.  Promotion is
disregarded.  If both players have at least 24 points the game is a draw
(called ``Jishogi'').  If a player has less, he loses the game.

Of course, a player can refuse to count pieces when he still has mating
chances or chances to gain material which would affect the outcome of
the counting.  There is no strict rule about what to do if this is not
the case, but nonetheless a player refuses to count up (e.g. because he
does not have enough points for a draw).  It has been generally accepted
that in such a case the game ends and the pieces are counted after one
player has managed to get all his pieces protected in the promotion
zone.

@end enumerate

@sp 1

@c Handicaps.

@node       Handicaps, Notes for chess players, Draws, The rules of shogi
@subsection Handicaps
@cindex     Handicaps

Unlike international chess, shogi has a well-established handicap system
which is used when players of different strengths play against each
other.  Handicaps range from small to huge, which makes it possible for
weak players to play against even very strong players and have an even
chance of winning.

Shogi players are ranked as follows: the weakest rank is around 15
``kyu'', which represents a beginner.  14 kyu is higher than 15 kyu, 13
kyu is higher still, and so on until you get to 1 kyu.  The next highest
rank is 1 ``dan'', followed by 2 dan, 3 dan and so forth.  The highest
amateur rank is 6 dan; professionals go up to 9 dan.  However,
professional ranks are not the same as amateur ranks; a professional 1
dan is @emph{much} stronger than an amateur 1 dan.  This system is
similar to that used by go players (and also other Japanese sports such
as karate).

A handicap consists of the stronger player playing White and removing
one or more pieces from his side of the board at the start of the game.
These pieces are permanently removed from play; they are not in hand.

The following is a list of the accepted handicaps, from weakest to
strongest.  The degree of the handicap, represented by the position in
the list, represents the difference in rank between the two players for
which the handicap is appropriate.  These rules are taken from the books
``Shogi for Beginners'' by John Fairbairn and ``The Art of Shogi'' by
Tony Hoskings (@pxref{References and links}) and, I believe, represent
current Japanese practice.

@sp 1

@enumerate

@item 
The stronger player removes his left lance (on 1a).

@item 
The players play a two-game match; in the first game the stronger player
removes his left lance (on 1a), while in the second game he removes his
bishop.

@item 
The stronger player removes his bishop.

@item 
The stronger player removes his rook.

@item 
The stronger player removes his rook and left lance.

@item 
The players play a two-game match; in the first game the stronger player
removes his rook and left lance (on 1a), while in the second game he
removes his rook and bishop.

@item 
The stronger player removes his rook and bishop.  This is usually called
a ``two-piece'' handicap.

@item 
The stronger player removes his rook, bishop, and both lances.  This is
called a ``four-piece'' handicap.

@item 
The stronger player removes his rook, bishop, both lances, and both
knights.  This is called a ``six-piece'' handicap.

@item 
The stronger player removes his rook, bishop, both lances, both knights,
and both silvers.  This is called an ``eight-piece'' handicap.

@end enumerate

@sp 1

Another advantage of playing handicap games is that the handicaps alter
the optimal strategy for both players.  For instance, handicaps all have
their own opening lines which may bear little or no resemblance to those
used in non-handicap shogi.  This means that when learning handicap
shogi, you are essentially learning completely new games which use the
same equipment!

The reader may wonder how on earth a player giving an eight-piece
handicap, say, could possibly hope to win.  Don't forget, though, that
in shogi the opponent's pieces can be captured and then become part of
one's own army.  Thus, if the opponent plays badly enough, the number of
pieces will soon even out.


@c Notes for chess players.

@node       Notes for chess players,  , Handicaps, The rules of shogi
@subsection Notes for chess players

Here are a few miscellaneous things that may confuse chess players.
Some of these have been mentioned elsewhere, but they bear repeating.

@sp 1

@enumerate
@item There is no queen.

@item Pawns capture the same way they move.  There is no initial
two-space pawn move and no @emph{en-passant} move.

@item There is no special castling move.  There @emph{are} a large
number of possible defensive formations referred to as ``castles''
(@pxref{Sample game}) but there is no need for special moves to create
them.

@item A given piece can only promote to @emph{one} other kind of piece.

@end enumerate

@sp 1

@c 
@c Sample game.
@c 

@node    Sample game, Mating problems, The rules of shogi, About shogi
@section Sample game
@cindex  Sample game

@c This will have to be spruced up for the TeX version...

This game was annotated by Pieter Stouten (@pxref{References and
links}).  I have made some minor corrections.  Note that captures are
denoted by the ``x'' symbol e.g. Rx3f and drops are denoted by the ``*''
symbol e.g. R*3f.  Check is indicated by a ``+'' after the move,
e.g. R3f+.  I recommend you use gnushogi/xshogi to play along with this
game.  In xshogi simply hit the ``Force Moves'' button after starting
up, while in gnushogi enter the word ``force'' at the prompt.  This will
allow you to enter moves for both sides.

Note also that the move numbering system used here is the chess-type
system where one move means one move by each player.  The Japanese count
one move made by each player as two moves.

---------------------------------------------------------------------------

Below you will find (the English translation of) an annotated game which
was published in the Dutch Shogi magazine ``81'' and in the Dutch
beginners booklet.  It has proven to be a very useful game to explain
some basic principles of Shogi.  Also, it is a rather straightforward
game compared to professional games where in most cases very diffuse
middle game fights take place.

   Pieter Stouten, 14th May 1990.

---------------------------------------------------------------------------

Black: Michael Trent (1-dan).  White: David Murphy (2-dan).

   1. P2f P3d  2. P2e B3c @*
[ This move is necessary, as otherwise white can exchange pawns: 3. P2d
Px2d 4. Rx2d.  He would thus get a pawn in hand and open up his rook
file. ]

   3. P7f P4d @*
[ White closes the bishop diagonal again.  He plans to play ranging rook
(the rook goes to 5b, 4b, 3 or 2b; a defensive strategy) and in that
case he'd better avoid an exchange of bishops.  One of the reasons is
that he will have problems developing his pieces without leaving holes
for bishop drops. ]

   4. S4h R3b  5. P3f S4b  6. K6h K6b @*
[ In general the rook plays an important role in the attacks.  It is
wise to move the king away from the area where the initial fights will
be and both players act according to the Shogi proverb ``keep the rook
and king apart''. ]

   7. K7h K7b  8. P5f P5d  9. G4i-5h G4a-5b @*
[ Both players use their second gold general to build their castle. ]

   10. S6h @*
[ In itself this move is not bad.  However, it will become clear that
black plans a quick attack and in that case it is wiser to omit this
move. ]

   10... S5c  11. P1f P1d @*
[ The advance of the edge pawns must be timed very well.  The remark at
black's tenth move applies here too: this move is good if black wants to
play a slow game, because it eliminates a future B1e. ]

   12. P4f K8b  13. N3g S7b @*
[ Black develops his knight in order to start an attack over the second,
third and fourth files.  White strengthens his king's position and
awaits the attack.  He aims at a counterattack as soon as black has
broken through into the white camp.  Probably white's breakthrough will
take place later, but he has good compensation in the form of a stronger
castle.  This theme occurs very often in static rook versus ranging rook
games. ]

   14. P4e R4b @*
[ Black starts his attack and white puts up a very passive defence.  His
rook has a hard task now to penetrate the black position.  Moreover, he
blocks his own bishop.  It seems much better to start a counterattack
with 14... P3e, later to be followed by B2b, B5a or Bx4d in order to use
his rook more actively. ]

   15. Px4d Sx4d  16. P*4e S5c @*
[ 16... Sx4e is more active.  A silver general is normally more valuable
than a knight, but white gets two pawns in hand and black none, while
the knight might come in handy for white too. ]

   17. Bx3c+ Nx3c  18. P2d Px2d @*
[ Black threatens to break through and white has to consider taking the
pawn on 2d or starting a counterattack with Nx4e.  If he chooses the
latter, black can play Px2c+ followed by +P3c.  The disadvantage is the
black ``tokin'' (=promoted pawn) that white will get in his camp; the
advantage is that it will cost black two more moves to promote his rook.
Because white did not trust that the result after engaging in a
``semeai'' (=mutual attack) with 18...Nx4e would give a positive result,
he captured the pawn on 2d.  Making the right decision in moments like
this often makes the difference between a win and a loss: miss one
attacking chance and you will be forced to defend the whole game until
the unavoidable defeat; on the other hand, an unsound attack can destroy
all ``aji'' (=potential, meaning possibilities, threats) without getting
anything in return. ]

   19. Rx2d Nx4e  20. Nx4e Rx4e  21. R2a+ P*4g @*
[ Now it becomes clear why black's 10. S6h was not good.  Had this move
been omitted, then white would not have had the time to play 13... S7b
and after R2a+ the gold on 6a would hang.  Thus black would have kept
``sente'' (=initiative).  Instead of 21... P*4g, B*6d is a very good
move, because after 22. P*2h black does not have a pawn in hand anymore
and he is being threatened with the annoying 22... N*4f 23. G5g N3h+
24. S4g +N4h also.  Black can also counter 21... B*6d with 22. N*3g.
White would then reply with 22... R4b 23. B*3c P*4g 24. Bx4b+ Sx4b.  The
white rook has played its role and instead of spending moves on saving
it white starts to scatter black's defences by successive pawn drops on
the fourth file: 25. Gx4g P*4f 26. G5g N*6e 27. G5h P4g+ 28. Gx4g P*4f.
This analysis was provided by Kato Hifumi, 9-dan professional (the
highest regular grade).  Destroying the coherence of the enemy pieces
(their shape) by dropping pawns is one of the most important Shogi
techniques.  With the actual move 21... P*4g white missed a good
chance. ]

   22. Sx4g P*4f  23. B*3g Px4g+  24. +Rx6a +Px3g @*
[ 23. B*3g seems pointless, but a closer look reveals that it is
actually quite mean.  On move 24 white cannot capture black's ``Ryu''
(=dragon =promoted rook) with his silver: 24... Sx6a 25. N*7d K7b
26. G*8b mate.  By attacking the front of the white castle and
threatening to mate him there, black has the chance to break down the
white defences from the side. ]

   25. +Rx5b S*6b @*
[ Here 25... B*4d would be much better, because it is defensive and
attacking at the same time.  After e.g. 26. G*4c Bx9i+ 27. Gx5c black
threatens 28. +Rx7b Kx7b 29. S*6a K8b 30. S*7a Kx7a 31. G*7b mate.
White is one move quicker, however.  He has the following beautiful
``tsume'' (mating sequence where every move is check): 27... N*8f 28. Px8f
S*8g 29. Kx8g B*9h 30. K7h Bx8i+ 31. K8g +B8i-8h 32. K9f L*9e mate.
This illustrates the sharpness of Shogi: one move can make the
difference between winning and losing. ]

   26. P*4f Rx4f @*
[ This move eliminates white's last chances.  26... R4b 27. +Rx4b Sx4b
28. R*4a seems annoying, but after 28... B*3c 29. S7g B*3b white wins
the rook and with his ``tokin'' on 3g there still is some hope. ]

   27. N*6e +P4g @*
[ White cannot defend anymore, so he starts a desperate attack.  Black
does not lose the right track, however. ]

   28. Nx5c+ +Px5h  29. +Nx6b +Px6h  30. Gx6h N*8f  31. Px8f B*6i  32. Gx6i
   R4h+  33. N*6h +Rx6h  34. Gx6h S*8g  35. Kx8g N*9e  36. K7h Resigns @*
[ White resigns here, because after 36... B*8g 27. K7g his attack has
petered out. ]

@page


@c 
@c Mating problems.
@c 

@node    Mating problems, Shogi variants, Sample game, About shogi
@section Mating problems

One good way to improve at shogi is to solve mating problems.  There are
several types of these problems, but the most common is called a
``tsume-shogi'' problem, or ``tsume'' problem for short.  In a tsume
problem, all pieces that are not on the board are assumed to be in the
opponent's hand (except for your King, which is usually not shown).
Every move you make must be check until the final checkmate.  Your
opponent may play any piece on the board or drop any of his pieces in
hand in order to prevent the mate.  In a properly constructed tsume
problem, all of your pieces on the board and in hand must be essential
to the solution.  One consequence of this is that all of your pieces in
hand must be played during the solution.  There should only be one
correct solution for the given number of moves.  Tsume problems use
Japanese-style move numbering; thus, a problem where you move (and give
check), your opponent moves, and you move to give checkmate is called a
three-mover.  Here is a really trivial three-mover:

@sp 1

@ifinfo

   3    2    1            @*
----------------+         @*
|    |    |    |  a       @*  
----------------+         @*  
|    |    | wK |  b       @*  
----------------+         @*  
|    |    |    |  c       @*
----------------+         @*
| bN |    |    |  d       @*
----------------+         @*
|    |    |    |  e       @*
----------------+         @*
|    | bN |    |  f       @*
----------------+         @*

@sp 1

Black in hand: S, G

@end ifinfo


@tex
\def\startline{\par\nobreak\noindent}

{\obeylines\obeyspaces%
\gdef\beginVerbatim{\bigbreak%
\begingroup%
\parskip=0pt%
\obeylines\obeyspaces%
\let^^M=\startline%
\tt}}
\gdef\endVerbatim{\endgroup\bigbreak}
\beginVerbatim

   3    2    1            
----------------+         
 |    |    |    |  a         
----------------+           
 |    |    | wK |  b         
----------------+           
 |    |    |    |  c       
----------------+         
 | bN |    |    |  d       
----------------+         
 |    |    |    |  e       
----------------+         
 |    | bN |    |  f       
----------------+
     
Black in hand: 2G

\endVerbatim
@end tex

@sp 1

Here, Black plays G*2b, White plays K1c, and Black plays G*1d mate.
More typical tsume problems range from 5 moves to arbitrarily high
numbers of moves, and they can be quite brain-busting.  Tsume problems
may seem artificial, but in the closing stages of the game where both
players have a lot of pieces in hand, it is often necessary to give
check at every move, or else your opponent will start a counterattack
and will mate you before you mate him.  A tsume problem is a worst-case
scenario for the attacker: you have to mate your opponent even though he
has every piece not on the board in hand, which means you have to
develop sharp attacking skills.  Many more tsume problems can be found
on the internet; I particularly recommend Patrick Davin's ``Shogi
Nexus'' (@pxref{References and links}).

@page

@c 
@c Shogi variants.
@c 

@node    Shogi variants, Differences between shogi and chess, Mating problems, About shogi
@section Shogi variants
@cindex  Shogi variants
@cindex  Variants
@cindex  Tori Shogi
@cindex  Wa Shogi
@cindex  Chu Shogi
@cindex  Dai Shogi
@cindex  Tenjiku Shogi
@cindex  Dai-dai Shogi
@cindex  Maka-dai-dai Shogi
@cindex  Tai Shogi
@cindex  Kyoku Tai Shogi

Several historical variants of shogi exist.  Most of these were invented
before modern shogi (in some cases hundreds of years before), are much
larger than modern shogi and are not played with drops.  Thus, in many
ways they are really more like giant chess games than like modern shogi.
The only one of these games to have survived in Japan is Chu (middle)
shogi, which is still played a little bit.  Thanks to the efforts of
George Hodges and John Fairbairn of the Shogi Association (two British
shogi enthusiasts), these games were resurrected and rules and sets for
them can still be purchased from George Hodges (@pxref{References and
links}).  I hope to eventually extend GNU shogi so that it can play at
least some of these games.  There are also several non-historical
variants of shogi; I don't know much about them but you can find
information about them on the internet (@pxref{References and links}).

The historical variants include:

@sp 1

@enumerate

@item
Tori (bird) shogi, played on a 7x7 board with 32 pieces in all; this is
the only variant that is known to have been played with drops.

@item
Wa shogi, played on an 11x11 board with 54 pieces.  This game can be
played with or without drops but the historical evidence favors the view
that it was played without drops.  However, most people who have tried
it claim it is a much better game with drops, being even more intricate
than standard shogi.

@item
Chu (middle) shogi, played on a 12x12 board with 92 pieces.  This was
(and is) by far the most popular of the variants, and has 21 different
kinds of pieces in the starting line-up alone (along with several others
that appear upon promotion).  Unlike modern shogi, there are a
tremendous number of ranging pieces and the game is definitely not
played with drops.  There is also an amazing piece called the Lion which
has a double king move and can capture two pieces at once!  Chu shogi
has a small but fanatical following, some of whom consider it better
than modern shogi.

@item
Dai (great) shogi, played on a 15x15 board with 130 pieces.  Other than
the larger board, this game is very similar to Chu shogi.

@item
Tenjiku (exotic) shogi, played on a 16x16 board with 176 pieces.  This
game is possibly the most complex tactical game in existence.  There are
many astoundingly powerful pieces, including one (the Fire Demon) that
can capture up to eight opposing pieces in a single move!  Despite the
size of the game, checkmates can occur very suddenly (and often very
early on) if one player makes a wrong move.  Tenjiku also has a small
but fanatical following, one of whom (Colin Adams) has written a book on
the game which is available for download at
@uref{http://www.colina.demon.co.uk/tenjiku.html}.

@item
Dai-dai (great-great) shogi, played on a 17x17 board with 192 pieces.
The opening setup alone has 64 different kinds of pieces!  This game and
the larger ones that follow sound pretty outlandish, but they have
actually been played; a game of Dai-dai can supposedly be played in
about 12 hours.

@item
Maka-dai-dai (great-great-great) shogi, played on a 19x19 board with 192
pieces.  For those for whom Dai-dai shogi is just too small :-)

@item
Tai (grand) shogi, played on a 25x25 board with 354 pieces!  Until
recently, this was thought to be the biggest chess game ever devised,
but now there is...

@item
Kyoku tai (extremely grand?) shogi, played on a 36x36 board with 402
pieces.  The rules for this have just been unearthed in an old Japanese
book.  Hopefully someone will soon organize a postal Kyoku tai shogi
championship; maybe their distant ancestors could finish it :-)

It is thought that the really huge games (Dai-dai and up) were never
really played to any significant extent (gee, wonder why?) and were
devised merely so that the creators could have the fun of inventing
enormous games, amazing their friends and confounding their enemies.
However, the games up to Tenjiku shogi at least appear to be quite
playable, assuming one has the time.

@end enumerate

@sp 1

@c
@c Differences between shogi and chess.
@c

@node    Differences between shogi and chess,  ,  Shogi variants, About shogi
@section Differences between shogi and chess
@cindex  Shogi vs. Chess

Some differences between shogi and international chess have been
mentioned elsewhere in this document; I summarize them here for people
who are interested in game comparisons.  I won't try to deal with the
thorny question of which game is ``better'' although my bias may have
already come through :-) In fact, the drop rule makes the two games so
different in character that arguing over which game is better is like
comparing apples to oranges (you'd be better off comparing chess to Chu
shogi (@pxref{Shogi variants}).  However, I believe that if you are a
chess fan you'll really like shogi as well, and shogi is also popular
with many people who don't particularly like chess.

Here are the significant differences between chess and shogi:

@sp 1

@enumerate

@item
In shogi, captured pieces become the property of the capturer and can
re-enter play by being dropped onto almost any vacant square.  In chess,
captured pieces are out of the game.  Thus, in shogi, piece exchanges
complicate the play significantly while in chess they simplify it.

@item
The shogi board is 9x9; the chess board is 8x8.

@item
Shogi has five pieces with no counterpart in chess: the gold and silver
generals, the lance, the promoted rook and the promoted bishop.  Chess
has one piece with no counterpart in shogi: the queen.  The knight's
move in shogi is much more restrictive than in chess.  Pieces in shogi
generally have a much smaller range of movement than in chess (unless
they are in hand).

@item
In shogi, all pieces except the gold general and the king can promote,
but only to one kind of piece.  Promotion is easier in shogi because the
promotion zone is closer to the starting position of the pieces
(especially pawns).  In chess, only the pawn can promote, but it can
promote to any other piece except the king.

@item
In shogi, pawns capture the same way they move.  There is no initial
two-space pawn move and hence no @emph{en-passant} captures.  In chess,
pawns capture diagonally which means that opposing pawns can block each
other.

@item
In shogi, you only have one rook and one bishop.  Note that the bishop
is not restricted to only one ``color'' square (squares in shogi aren't
colored, but never mind) because promoted bishops can also move one
square orthogonally.

@item
There is no special castling move in shogi.  The term ``castle'' is
used in shogi to denote a defensive formation consisting of (usually)
three generals which protect the king.  There are many such castles
(about 40 or so have names).  @xref{Sample game}.

@item
Draws are much rarer in shogi than in chess.  Perpetual check is not
allowed.  Stalemate is a virtual impossibility, and is a loss for the
stalematee. 

@item
Since pieces are never out of play in shogi, chess-type endgames
involving only a few pieces do not occur.

@item
Shogi games are generally longer than chess games (about 60-70 moves is
typical).

@item
Shogi has a well-developed handicap system which is in general use;
chess does not.

@end enumerate

@sp 1

The effects of all these differences on play include (in my opinion):

@sp 1

@enumerate

@item
Piece/pawn structures in chess are more rigid than in shogi.  Pawns
block each other and pawns, once advanced, cannot ever retreat.  In
shogi, you can repair the hole caused by a pawn advance by exchanging
the pawn and dropping it back where you want it.  Thus shogi is more
fluid than chess and less ``structural''.

@item
Counterattack is MUCH more common in shogi than in chess.  Games
typically end in mutual mating attacks, where each player is trying to
checkmate the other player before being checkmated himself.  This makes
tempo incredibly important and also makes sacrificial play quite common.

@item
Attacks involving only ranging pieces are more a feature of chess than
of shogi.  A shogi attack typically uses a ranging piece or pieces to
support an attack by short-range pieces (especially generals).  It is
very rare to mate a king with a non-adjacent ranging piece in shogi
since the player whose king is threatened can almost always interpose by
dropping a piece.

@end enumerate

@sp 1


@c --------------------
@c gnushogi.
@c --------------------

@node    gnushogi, xshogi, About shogi, Top
@chapter gnushogi
@cindex  gnushogi

This section describes how to run the ``gnushogi'' program.

@sp 1

SYNOPSIS
     
@sp 1

gnushogi [ [[-]a] [-b bookfile] [-B binbookfile] [-C] [-h langfile] 
[-L langfile] [-r length] [-R] [-s pathname] [-l pathname] [-S binbooksize]
[-t] [-c size] [-T size] [-v] [-x] [-X] arg1 arg2 ]

@sp 1

DESCRIPTION

@sp 1

GNU shogi (gnushogi) plays a game of japanese chess (shogi) against the
user or it plays against itself.

At startup gnushogi reads the binbook file if it is present.  It then
looks for a book file.  If it is present it adds its contents to the
binbook data.  If the binbook file is writable a new combined binbook
file is written.

Gnushogi is a modified version of the gnuchess program.  It has a simple
alphanumeric board display, or it can be used with the xshogi program
under X windows.  The program gets its opening moves from the file
gnushogi.bbk which is located in a directory specified in the Makefile.
To invoke the program type:

@sp 1

@table @samp

@item  gnushogi -C
simple curses based version

@item  gnushogi -X (or just gnushogi)
xshogi compatible version

@item gnushogi -R
raw test display version
@end table

@sp 1

TIME CONTROLS

@sp 1

If one argument is given, it is the search time per move in
[minutes:]seconds.  So gnushogi 30 will generate one move every 30
seconds, while gnushogi 5:00 will generate one move every 5 minutes.

If two or more arguments are given, they will be used to set tournament
time controls with the first argument of each pair being the number of
moves and the second being the total clock time in minutes[:seconds].
Thus, entering gnushogi 60 5 will set the clocks for 5 minutes (300
seconds) for the first 60 moves, and gnushogi 30 3:30 will allow 3
minutes and 30 seconds for 30 moves.

gnushogi 30 5 1 :30 will allow 5 minutes for the first 30 moves and 30
seconds for each move after that.  Up to 4 pairs of controls may be
specified.

If no argument is given the program will prompt the user for level of
play.

For use with xshogi see the documentation on that program.
@xref{xshogi}.

@sp 1

@page

BOOK

@sp 1

The book gnushogi.tbk consists of a sequence of openings.  An opening
begins with a line starting with a # (the rest of the line is a comment).
Following this is a series of moves in algebraic notation alternating
between black and white separated by whitespace.  A move may have a ?
after it indicating this move should never be made in this position.  Moves
are stored as position:move so transpositions between openings can take
place.

@sp 1

HASHFILE

@sp 1

The hashfile if created should be on the order of 4 megabytes; you can
create such a hashfile by typing ``gnushogi -c 22'' (see below).  This
file contains positions and moves learned from previous games.  If a
hashfile is used the computer makes use of the experience it gained in
past games.  Tests run so far show that it plays no worse with the
hashfile than without, but it is not clear yet whether it provides a
real advantage.

@sp 1

LEGAL MOVES

@sp 1

Note: Piece letters are determined by the language file.  What is
specified here is the default (English).

Once gnushogi is invoked, the program will display the board and prompt
the user for a move.  To enter a move, use the notation 7g7f where the
first letter-number pair indicates the origin square and the second
letter-number pair indicates the destination square.  An alternative is
to use the notation P7f where the first letter indicates the piece type
(P,L,N,S,G,B,R,K).  To promote append a + the type of the new piece to
the move, as in 2d2c+ or P2c+. Note that you must use capital letters
for the pieces by default.

@sp 1

COMMAND-LINE OPTIONS

@sp 1

@table @samp

@item -a
Do not search on opponent's time.

@item a
Do search on opponent's time.

@item -b @var{bookfile}
Use bookfile for opening book.

@item -B @var{binbookfile}
Use binbookfile for binary opening book.

@item -c @var{size}          
Create a new HASHFILE.  File size is 2^size entries of approximately 65+?
bytes.

@item -C
Use curses-based display mode.

@item -h   
Do not use hashfile.

@item h    
Do use hashfile.

@item -l @var{pathname}
Pathname of the loadfile used with get or xget.

@item -L @var{lang}
Use language lang from the file gnushogi.lang.  If -L is not specified
it uses the first language in the file.

@item  -P @var{plylevels}
Number of plys to include in the binbookfile.  For generating a
binbookfile.

@item  -r @var{length}
Rehash @emph{length} times in searching entries for position in
transposition table.

@item  -R  
Use raw text display mode.  This can be used for dumb terminals or for
systems that don't have curses.

@item  -s @var{pathname}
Pathname of the save file to use with the save command.

@item  -S @var{size}
Size of binbookfile for memory based books.  For creating a binbookfile.

@item  -t   
Show statistics for HASHFILE.

@item  -T @var{size}
Set the transposition table size to 2^size entries.

@item  -v   
Show version and patchlevel.

@item  -x @var{value}
Use value as the evaluation window xwndw.

@item  -X   
Use xshogi display mode (the default).

@end table

@sp 1

COMMANDS

@sp 1

In addition to legal moves, the following commands can be entered at the
gnushogi prompt.  Note: command names are determined by the language
file and may vary with the implementation.  The default language is
English.

@table @samp

@item alg
allow algebraic input (not implemented).

@item Awindow 
change Alpha window (default score + 90).

@item Bwindow 
change Beta window (default score - 90).

@item beep 
toggles beeping after each move (default: on).

@item bd 
updates the current board position on the display.

@item book 
turns off use of the opening library.

@item both 
causes the computer to play both sides of a shogi game.

@item black 
causes the computer to play as White, if the computer was to move
first.

@item bsave 
saves a game to disk as a book textfile.  The program will prompt the
user for a file name.

@item gamein 
toggles game mode time control.  Assumes the time specified for time
control is the time for a complete game.  Input with the level command
should be the game time and the expected number of moves in a game.  go
command must be given.

@item coords 
show coordinates on the display (visual only).

@item contempt 
allows the value of @emph{contempt} to be modified.

@item debug 
asks for a piece as color piece, as wb or bn, and shows its calculated
value on each square.

@item debuglevel 
sets level of debugging output if compiled with debug options.

@item depth 
allows the user to change the search depth of the program.  The maximum
depth is 29 ply.  Normally the depth is set to 29 and the computer
terminates its search based on elapsed time rather than depth.  If depth
is set to (say) 4 ply, the program will search until all moves have been
examined to a depth of 4 ply (with extensions up to 11 additional ply
for sequences of checks and captures).  If you set a maximum time per
move and also use the depth command, the search will stop at the
specified time or the specified depth, whichever comes first.

@item easy 
toggles easy mode (thinking on opponents time) on and off. The default
is easy mode ON.  If easy mode is disabled, the keyboard is polled for
input every so often and when input is seen the search is terminated. It
may also be terminated with a sigint.

@item edit 
allows the user to set up a board position.
@itemize @minus

@item #    
clear the board.

@item c
toggle piece color.

@item .
command will exit setup mode.

@item p3b
place a pawn on 3b

@item p3b+
place a promoted pawn on 3b

@item p*
place a pawn in hand (among the captured pieces)

@end itemize

Pieces are entered by typing a letter (p,l,n,s,g,b,r,k)  for
the piece followed by the coordinate.  Here, letter case is ignored.

The usual warning about the language file applies.

@item exit 
exits gnushogi.

@item first 
tells the computer to move first.  Computer begins searching for a move.
(same as ``go'').

@item force 
allows the user to enter moves for both sides.  To get the program to
play after a sequence of moves has been entered use the ``black'' or
``white'' commands.

@item get 
retrieves a game from disk.  The program will prompt the user for a file
name.

@item go 
tells the computer to move first.  Computer begins searching for a move.
(same as ``first'').

@item hash 
use/don't use hashfile.

@item hashdepth 
allows the user to change the minimum depth for using the hashfile and
the number of moves from the beginning of the game to use it.

@item help 
displays a short description of the commands and the current status of
options.

@item hint 
causes the program to supply the user with its predicted move.

@item level 
allows the user to set time controls such as 60 moves in 5 minutes etc.
In tournament mode, the program will vary the time it takes for each
move depending on the situation.  If easy mode is disabled (using the
``easy'' command), the program will often respond with its move
immediately, saving time on its clock for use later on.

@item list 
writes the game moves and some statistics on search depth, nodes, and
time to the file ``shogi.lst''.

@item material 
toggle material flag - draws on no pawns and both sides < rook.

@item new 
starts a new game.

@item p 
evaluates the board and shows the point score for each piece.  The total
score for a position is the sum of these individual piece scores.

@item post 
causes the program to display the principal variation and the score
during the search.  A score of 100 is equivalent to a 1 pawn advantage
for the computer.

@item quit 
exits the game.

@item random 
causes the program to randomize its move selection slightly.

@item rcptr 
set recapture mode.

@item remove 
backout the last level for both sides.  Equal to 2 undo's.

@item reverse 
causes the board display to be reversed.  That is, the Black's pieces will
now appear at the top of the board.

@item rv 
reverse board display.

@item save 
saves a game to disk.  The program will prompt the user for a file name.

@item switch 
causes the program to switch places with the opponent and begin
searching.

@item test 
performs some speed tests for MoveList and CaptureList generation, and
ScorePosition position scoring for the current board.

@item time 
set computer's time remaining, intended for synchronizing clocks among
multiple players.

@item tsume 
toggle tsume mode. In tsume mode, not all possible moves will be
generated. If a king is in check, only moves that get the king out of
check are generated.  If the king is not in check, only moves that give
check to the opponent's king are generated.

@item undo 
undoes the last move whether it was the computer's or the human's.  You
may also type ``remove''.  This is equivalent to two ``undo'''s
(e.g. retract one move for each side).

@item white 
causes the computer to play as Black; if the computer is to move
first the go command must be given.

@item xget 
read an xshogi position file.

@item xsave 
save as an xshogi position file.

@item xwndw 
change X window. The window around alpha/beta used to determine whether
the position should be scored or just estimated.  Note: this has
@emph{nothing} to do with xshogi or X windows; the terms are completely
separate.

@end table

@sp 1


@c --------------------
@c xshogi.
@c --------------------

@node    xshogi, References and links, gnushogi, Top
@chapter xshogi
@cindex  xshogi

This section describes how to run the ``xshogi'' program.

@sp 1

SYNOPSIS

@sp 1

xshogi [ options ]

@sp 1

DESCRIPTION

@sp 1

xshogi provides an X11/Xt/Athena Widgets user interface for gnushogi.
With xshogi you can play gnushogi, set up arbitrary positions, force
variations, or watch xshogi manage a game between two shogi programs.
Furthermore, it can be used as an interface between two players on
different displays.

xshogi can also be used as a shogi board to play out games.  It will
read through a game file or allow a player to play through a variation
manually (force mode).  This is useful for keeping track of email postal
games or browsing games off the net.

After starting xshogi, you can make moves by pressing mouse button 1
while the cursor is over a square with your piece on it and dragging the
mouse to another square.  If the move is illegal, gnushogi will not
allow it.  xshogi will then retract the move.

@sp 1

COMMAND-LINE OPTIONS

@sp 1

The following command line options also correspond to X resources that
you can set in your .Xdefaults file.

@sp 1

@table @samp

@item [standard Xt options]
xshogi accepts standard Xt options like -display, -geometry, and
-iconic.

@item -tc or -timeControl minutes[:seconds]
Amount of time for a set of moves determined by movesPerSession.  If
this number of moves is played within the time control period, xshogi
resets the time clocks.  Default: 5 minutes.

@item -mps or -movesPerSession moves
Number of moves in a time control period.  Default: 40 moves.

@item -st or -searchTime minutes[:seconds]
Tell gnushogi to spend at most the given amount of time searching for
each of its moves.  Without this option, gnushogi 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 -sd or -searchDepth number
Tell gnushogi to look ahead at most the given number of moves when
searching for a move to make.  Without this option, gnushogi chooses
its search depth 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 -clock or -clockMode (True | False)
Determines whether or not to use the clock.  If clockMode is False, the
clock does not run, but the side that is to play next is still
highlighted.

@item -td or -timeDelay seconds
Time delay between moves during ``Load Game''.  This doesn't have to be
a round number.  Try -td 0.4.  Default: 1 second.

@item -nsp or -noShogiProgram (True | False)
If this option is True, xshogi acts as a passive shogi board; it does
not try to start a shogi program, not even to check whether moves made
in Force mode are legal.  It also sets -clockMode to False.  Default:
False.

@item -fsp or -firstShogiProgram program
Name of first shogi program.  In matches between two machines, this
program plays white.  Default: ``gnushogi''.

@item -ssp or -secondShogiProgram program
Name of second shogi program, if needed.  In matches between two
machines, this program plays black; otherwise it is not started.
Default: ``gnushogi''.

@item -fh or -firstHost host
Name of host the first shogi program plays on.  Default: ``localhost''.

@item -sh or -secondHost host
Name of host the second shogi program plays on.  Default: ``localhost''.

@item -rsh or -remoteShell shell_name
Some systems do not use rsh as the remote shell.  This option allows a
user to name the remote shell command.  This should be done in the
resource file.

@item -mm or -matchMode (False | Init | Position | Opening)
Automatically run a game between firstShogiProgram and
secondShogiProgram.  If matchMode is set to Init, xshogi will start the
game with the initial shogi position.  If matchMode is set to Position,
xshogi will start the game with the position specified by the
loadPositionFile resource.  If matchMode is set to Opening, xshogi will
play out the opening moves specified by the -loadGameFile resource.  If
the -saveGameFile resource is set, a move record for the match will be
saved in the specified file.  Default: ``False''.

@item -lgf or -loadGameFile file
Name of file to read a game record from.  Game files are found in the
directory named by the SHOGIDIR environment variable.  If this variable
is not set, the current directory is used unless the file name starts
with a /.

@item -lpf or -loadPositionFile file
Name of file to read a game position from.  Position files are found in
the directory named by the SHOGIDIR environment variable.  If this
variable is not set, the current directory is used unless the file name
starts with a /.

@item -sgf or -saveGameFile file
Name of file to save a game record to.  Game files are saved in the
directory named by the SHOGIDIR environment variable.  If this variable
is not set, the current directory is used unless the file name starts
with a /.

@item -spf or -savePositionFile file
Name of file to save a game position to.  Position files are saved in
the directory named by the SHOGIDIR environment variable.  If this
variable is not set, the current directory is used unless the file name
starts with a /.

@item -coords or -showCoords (True | False)
If this option is True, xshogi displays algebraic coordinates along the
board's left and bottom edges.  The default is False.  The coordFont
resource specifies what font to use.

@item -mono or -monoMode (True | False)
Determines whether xshogi displays its pieces and squares with two
colors or four.  You shouldn't have to specify monochrome.  xshogi will
determine if this is necessary.

@item -pc or -pieceColor color
Color specification for pieces suitable for XParseColor().
Default: #FFFFD7.  

@item -sc or -squareColor color
Same for squares.  Default: #EBDFB0.

@item -wps or -westernPieceSet (True | False)
Choose the Western style piece set.

@item -npb or -normalPawnBitmap file
@item -nnb or -normalKnightBitmap file
@item -nbb or -normalBishopBitmap file
@item -nrb or -normalRookBitmap file
@item -nkb or -normalKingBitmap file
Names of the bitmap files for the bitmap piece icons.

@item -rpb or -reversePawnBitmap file
@item -rnb or -reverseKnightBitmap file
@item -rbb or -reverseBishopBitmap file
@item -rrb or -reverseRookBitmap file
@item -rkb or -reverseKingBitmap file
Names of the bitmap files for the outline piece icons.

@item -debug or -debugMode (True | False)
Turns on debugging printout.

@end table

@sp 1

@page

OTHER X RESOURCES

@sp 1

@table @samp

@item initString
The actual string that is sent to initialize the shogi program can be
set from .Xdefaults.  It can't be set from the command line because of
syntax problems.  The default value is ``new\nbeep\nrandom\neasy\n''.
The ``new'' and ``beep'' commands are required. You can remove the
``random'' command if you like; including it causes gnushogi to
randomize its move selection slightly so that it doesn't play the same
moves in every game.  Even without ``random'', gnushogi randomizes its
choice of moves from its opening book.  You can also remove ``easy'' if
you like; including it toggles easy mode off, causing gnushogi to think
on your time.  That is, if ``easy'' is included in the initString, GNU
Shogi thinks on your time; if not, it does not.  (Yes, this does seem
backwards, doesn't it.)  You can also try adding other commands to the
initString; see the gnushogi documentation (@pxref{gnushogi}) for
details.

@item blackString and whiteString
These resources control what is sent when the Machine Black and Machine
White buttons are selected.  This is mostly for compatibility with
obsolete versions of gnushogi.

Alternate bitmaps for piece icons can be specified either by choosing
one of the built-in sets or with the file name resources described
above.  There are three built-in sets of piece bitmaps available, large
(the default), medium, or small.  It is easiest to select the set you
prefer in the .Xdefaults file:

     XShogi*boardSize:   Medium

The font used for button labels and comments can be changed in the
.Xdefaults file.  You may want to choose a smaller font if you are using
the small pieces:

     XShogi*font:    helvetica_oblique12

The font used for coordinates (when the showCoords option is True) can
be set similarly:

     XShogi*coordFont:    helvetica_10

If you are using a grayscale monitor, try setting the colors to:

     XShogi*pieceColor:     gray100 @*
     XShogi*squareColor:    gray60  @*

@end table

@sp 1

COMMAND BUTTONS AND KEYS

@sp 1

@table @samp

@item Quit    
Quits xshogi.  Q or q is a keyboard equivalent.

@item Reset   
Resets xshogi to the beginning of a shogi game.  It also deselects any
game or position files.

@item Flip View
inverts the view of the shogi board.

@item Hint    
displays a move hint from gnushogi.

@item Load Game
plays a game from a record file.  If no file is specified a popup dialog
asks for a filename.  Game files are found in the directory named by the
SHOGIDIR environment variable.  If this variable is not declared then
the current directory is used unless the file name starts with a /.  G
or g is a keyboard equivalent.  The game file parser will accept almost
any file that contains moves in algebraic notation.  If the first line
begins with `#', it is assumed to be a title and is displayed.  Text
enclosed in parentheses or square brackets is assumed to be commentary
and is displayed in a pop-up window.  Any other text in the file is
ignored.

@item Load Position
sets up a position from a position file.  If no file is specified a
popup dialog asks for a filename.  Position files are found in the
directory named by the SHOGIDIR environment variable.  If this variable
is not declared then the current directory is used unless the file name
starts with a /.  Position files must be in the format that the Save
Position command writes.

@item Save Game
saves a game to a record file.  If no file is specified a popup dialog
asks for a filename.  If the filename exists, the user is asked whether
the current game record is be appended to this file or if the file
should be replaced.  Game files are saved in the directory named by the
SHOGIDIR environment variable.  If this variable is not declared then
the current directory is used unless the file name starts with a /.
Game files are human-readable, and can also be read back by the Load
Game command. Furthermore, they are accepted as gnushogi text bookfiles.

@item Save Position
saves a position to a position file.  If no file is specified a popup
dialog asks for a filename.  Position files are saved in the directory
named by the SHOGIDIR environment variable.  If this variable is not
declared then the current directory is used unless the file name starts
with a /.  Position files are human-readable, and can also be read back
by the Load Position command.

@item Machine White
forces gnushogi to play white.

@item Machine Black
forces gnushogi to play black.

@item Force Moves
forces a series of moves.  That is, gnushogi stops playing and xshogi
allows you to make moves for both white and black.

@item Two Machines
plays a game between two computer programs.

@item Forward 
moves forward through a series of remembered moves.  F or f is a
keyboard equivalent.

@item Backward
moves backward through a series of remembered moves.  As a side effect,
puts xshogi into Force Moves mode.  B or b is a keyboard equivalent.

@item Pause   
pauses the clocks or (in Load Game mode) pauses the game being loaded.
Press Pause again to continue.  P or p is a keyboard equivalent.

@item Edit Position
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 black pieces (button 2) or white 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 Black or White indicator at the
top of the screen.

@item Challenge
allows you to make a two display game between two human players.  Enter
the display you want to connect to.  If you are allowed to connect, a
new board is displayed at the remote display.  Challenge mode can only
be stopped by pressing ``quit''.

@item Select Level
allows you to reset the clocks for both players.  Enter the number of
moves and the number of minutes in which the moves should be done.

@item Move NOW
force computer to stop thinking and to make the current best move.

@item Iconify I, i, C or c 
iconifies xshogi.

@end table

@sp 1

LIMITATIONS

@sp 1

If you press the  Pause  button  during  GNU  Shogi's  turn,
xshogi will stop the clocks, but gnushogi will still make a
move.

After a mate or draw when playing against gnushogi, if  you
back  up  with  the  Backward  button,  the clocks are reset
(because gnushogi has exited and must be restarted).

The game parser recognizes only algebraic notation.

@sp 1

AUTHORS

@sp 1

Original authors of XBoard:  Chris Sears and Dan Sears.

Enhancements for XBoard (Version 2.0):  Tim Mann.

Conversion to XShogi (Version 1.1):  Matthias Mutz.

Current maintainer: Mike Vanier.

@sp 1

COPYRIGHT INFORMATION

@sp 1

XShogi borrows its piece bitmaps from CRANES Shogi.

Copyright 1991 by Digital Equipment Corporation, Maynard, Massachusetts.
Enhancements Copyright 1992 Free Software Foundation, Inc.  Enhancements
Copyright 1993 Matthias Mutz.  Further enhancements copyright 1999 by
Michael Vanier and the Free Software Foundation, Inc.

The following terms apply to Digital Equipment Corporation's copyright
interest in XBoard:

All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Digital not be used in
advertising or publicity pertaining to distribution of the software
without specific, written prior permission.

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

The following terms apply to the enhanced version of XShogi distributed
by the Free Software Foundation:

This file is part of XSHOGI.

XSHOGI is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY.  No author or distributor accepts responsibility to anyone
for the consequences of using it or for whether it serves any particular
purpose or works at all, unless he says so in writing.  Refer to the
XSHOGI General Public License for full details.

Everyone is granted permission to copy, modify and redistribute XSHOGI,
but only under the conditions described in the XSHOGI General Public
License. A copy of this license is supposed to have been given to you
along with XSHOGI so you can know your rights and responsibilities.  It
should be in a file named COPYING.  Among other things, the copyright
notice and this notice must be preserved on all copies.


@c ---------------------
@c References and links.
@c ---------------------

@node    References and links, Acknowledgements, xshogi, Top
@chapter References and links
@cindex  References
@cindex  Books
@cindex  Mailing lists
@cindex  Web sites


There are very few English-language books for people learning shogi.
The two I recommend are:

@sp 1

@enumerate

@item
@cite{Shogi for Beginners, 2nd. Edition}, by John Fairbairn.  This is a
superb beginner's book in every way, covering all phases of the game.
It was out of print for a long time, but has now been reprinted and is
available either from Kiseido (@uref{http://www.labnet.or.jp/~kiseido})
or from George Hodges (see below).

@item
@cite{The Art of Shogi}, by Tony Hoskings.  This is one step up from the
Fairbairn book.  It covers a lot of ground, and is especially noteworthy
for its detailed treatment of opening lines.  You can order this book
from Amazon.com's UK branch (@uref{http://www.amazon.co.uk}).

@end enumerate

@sp 1

Another book you may find is @cite{Shogi: Japan's Game of Strategy} by
Trevor Leggett.  This book is very elementary and is somewhat outdated,
having been published first in 1966.  However, it does feature a paper
shogi board and punch-out pieces, so if you want a really cheap shogi
set you might pick this book up.  It is still in print.

Two books that are no longer in print but are definitely worth getting
if you find them are @cite{Guide to Shogi Openings} and @cite{Better
Moves for Better Shogi}, both by Aono Teriuchi.  They are published in a
bilingual edition (English/Japanese) and are the only books on shogi in
English written by a Japanese professional shogi player.  John Fairbairn
did the translation from Japanese to English.

Shogi sets are available from:

@sp 1

@quotation
George F. Hodges @*
P.O. Box 77 @*
Bromley, Kent @*
United Kingdom BR1 2WT
@end quotation

@sp 1

George also sells equipment for all the historical shogi variants
(@pxref{Shogi variants}) (except for Kyoku tai shogi) and also sells
back issues of the magazine ``Shogi'' which he published for 70 issues
in the late 70's to late 80's.  This magazine is STRONGLY recommended;
it contains more information about shogi in English than you will ever
find anywhere else.

Here are some useful URLs:

@sp 1

@table @asis

@item Pieter Stouten's shogi page: @uref{http://www.shogi.net}
This is the main shogi-related site on the internet, with links to
almost all the other sites.

@item Roger Hare's shogi page: @uref{http://www.ed.ac.uk/~rjhare/shogi}
This has lots of information, including full rules to most of the shogi
variants.

@item Patrick Davin's Shogi Nexus: @uref{http://www.vega.or.jp/~patrick/shogi/}
There's lots of cool stuff on this site; my favorite is the extensive
collection of Tsume-shogi (mating) problems, both for beginners and
more advanced players.

@item Steve Evans' shogi page: @uref{http://www.netspace.net.au/~trout/index.html} 
Steve has written a program that plays almost all of the shogi variants,
unfortunately it only runs on Windows :-(

@item Hans Bodlaender's chess variant pages: @uref{http://www.cs.ruu.nl/~hansb/d.chessvar}
This page has an almost unimaginable variety of rules for different
chess variants, including many shogi variants (historical and non-historical).

@end table

@sp 1

@c -----------------
@c Acknowledgements.
@c -----------------

@node    Acknowledgements, Bugs, References and links, Top
@chapter Acknowledgements
@cindex  Acknowledgements

I would like to thank the following people:

@sp 1

@itemize @bullet

@item
Matthias Mutz, who originally developed GNU shogi as a spin-off of GNU
chess and who very kindly let me take over the maintenance of this very
interesting project.

@item
Richard Stallman and the Free Software Foundation, for creating an
organization where anyone can contribute software for the common good of
all, for making GNU/Linux possible, and especially for writing emacs and
gcc, without which my working life would be intolerable.

@item
Georges Hodges, for starting the Shogi Association in England, without
which I would probably never have heard of shogi, for supplying shogi
equipment, for publishing the excellent magazine ``Shogi'' (now sadly
defunct), for personally answering all my silly questions by mail, and
for being the ambassador of shogi to the West.

@item
Pieter Stouten, for having the most comprehensive shogi site on the
World Wide Web (@uref{http://www.shogi.net}), and for
maintaining the shogi-l mailing list.  Go to Pieter's web site for more
information on subscribing to the list.  Also thanks to everyone who
contributes and has contributed to that list.

@item
Matt Casters, for testing GNU shogi.  Matt and I will be working
together on improving the solution engine in future versions of this
program.

@end itemize

@sp 1

@c -----
@c Bugs.
@c -----

@node    Bugs, Index, Acknowledgements, Top
@chapter Bugs

The motto of GNU shogi is ``100% bug-free or you don't pay!'' :-)  In the
extremely unlikely case (*ahem*) that you do find a bug, please send me
(Mike Vanier) an email at @email{mvanier@@cs.caltech.edu}.  Also, feel
free to send me comments, complaints, out-and-out raves, suggestions,
plane tickets to Hawaii, and/or large suitcases filled with unmarked,
untraceable hundred-dollar bills.


@c ============
@c End of body.
@c ============



@c ====
@c End.
@c ====

@node    Index,  , Bugs, Top
@chapter Index

@printindex cp

@contents

@bye