X-Git-Url: http://winboard.nl/cgi-bin?a=blobdiff_plain;f=installer%2FWinBoard-4.2.7%2FCrafty-WinBoard%2Fcrafty.doc.txt;fp=installer%2FWinBoard-4.2.7%2FCrafty-WinBoard%2Fcrafty.doc.txt;h=dda0725bfd92ff2b683fb4d085400727ff0b2821;hb=71a0dc43ed9498db72f4a302a4b11fabb93ab286;hp=0000000000000000000000000000000000000000;hpb=0b915ff9a9bf2c51ddd8e8c978125fffa3b2865c;p=xboard.git

diff --git a/installer/WinBoard-4.2.7/Crafty-WinBoard/crafty.doc.txt b/installer/WinBoard-4.2.7/Crafty-WinBoard/crafty.doc.txt
new file mode 100644
index 0000000..dda0725
--- /dev/null
+++ b/installer/WinBoard-4.2.7/Crafty-WinBoard/crafty.doc.txt
@@ -0,0 +1,2112 @@
+
+
+
+
+
+
+
+         Crafty Command Documentation (version 18)
+      -----------------------------------------------
+Crafty  is nothing more than a long-time hobby of mine, dat-
+ing back to Blitz and later Cray Blitz.  People ask me how I
+keep doing this, and that is the one question that generally
+leaves me at a loss for words.
+
+Perhaps the most common question I'm asked is "is this  ver-
+sion  of Crafty some dumbed-down version of what you play on
+ICC or what you use at a computer chess event?"  The  answer
+is a resounding *NO*.  The current version is *exactly* what
+is running on ICC under this version number.   Note  that  a
+new  version  can, on occasion, introduce weaknesses or out-
+right bugs that were not present  in  previous  "gold"  ver-
+sions.   As  a result, you should be careful to back up your
+"favorite" before trying the latest and  greatest.   If  you
+aren't  satisfied with the new version, you can then go back
+to what you believe is a better version.
+
+If you are looking for the strongest playing computer  chess
+program  available,  you should likely look to Fritz, Rebel,
+Tiger, and the other commercial  entries.   There  you  will
+find  strong  opponents  with  polished interfaces that have
+been tested in a systematic and careful  way.   If  you  are
+looking  for  a program that plays good chess, has a reason-
+able set of features for you to use, is available in  source
+form,  and  one  where the author welcomes feedback, code or
+suggestions, then you are at the  right  place.   I  welcome
+comments  and  suggestions, and also feedback from ideas you
+try yourself that seem to work.
+
+Crafty is a state-of-the-art  computer  chess  program,  and
+uses  all  of  the  search algorithms you have probably read
+about, negascout search, killer/history move  ordering,  SEE
+(Static  Exchange  Evaluation)  quiescence move ordering and
+pruning, hash (transposition/refutation) tables as  well  as
+evaluation caches, selective extensions, recursive null-move
+search, and a host of other features that have been used and
+are  still  being  used in most computer chess programs.  If
+it's not in Crafty, either it is on the "to do" list, or  it
+has been tried, found wanting, and discarded.
+
+Chess Knowledge is growing, and suggestions (or even better,
+real code) are welcome.  This is  the  best  place  to  con-
+tribute  your  ideas,  because knowledge can be used to sup-
+plant search and make it play  better.   The  evaluation  is
+probably  the easiest place to start studying Crafty because
+of the comments and simplicity of using bitmaps, *once*  you
+get "into" them.
+
+My  purpose  for doing this is an exercise in computer chess
+efficiency.  I can't begin to count the number of  people  I
+know  that  started  from  scratch to write a chess program.
+
+
+
+
+
+
+
+
+
+
+
+
+
+Even larger is the group that started from scratch, and gave
+up  before  finishing, because of the basic size of the pro-
+ject.
+
+Crafty offers everyone a very clean starting point,  if  you
+are  fascinated by the bitmap chess board implementation (as
+I  am).   The  search  and  quiescence  code  is  reasonably
+straightforward, as is the evaluation,
+
+It  offers a great starting point, so that if you are inter-
+ested in trying a new search extension, you can  be  testing
+tomorrow,  rather  than  next year, because you start with a
+fully functional chess engine that is not a  "toy"  applica-
+tion,  but is a functional and "dangerous" chess player.  It
+offers a rapid start, although you can certainly replace  it
+piece  by  piece  until  it is "yours" if you want.  It also
+offers a fairly complete set of commands  and  an  interface
+for  a GUI as well as support for chess server play, so that
+testing and debugging your new ideas is greatly  simplified.
+
+If you'd like more information, please check out the read.me
+document  and  the  crafty.FAQ  that  are  distributed  with
+Crafty.  These contain recent news and specific instructions
+for commonly asked  questions,  like  "where  can  I  obtain
+tablebase files and how do I use them?"
+                    How to play a game.
+                    -------------------
+When  you execute Crafty, you will immediately be greeted by
+the prompt string "white(1): " and Crafty will wait for com-
+mands.  This prompt means it is white on move, and we are at
+move #1 for white.  You can first use any  of  the  commands
+from the alphabetic command listing below to tailor the game
+to your liking (time control, hash table size, book  random-
+ness,  etc.)  and then you have two choices.  If you want to
+play white, just enter your move, and Crafty  will  take  it
+from  there  and  make a move in response.  You will then be
+prompted by "white(2):" and it is your move again.   If  you
+would prefer to play black, just enter either "move" or "go"
+at the prompt and crafty will move for that side rather than
+accepting  a  move  from  you.   After it makes its move for
+white, you will then see the prompt "black(1): "  indicating
+it is now time for blacks first move.  You can enter a move,
+or you can once again enter "move" or "go" and  Crafty  will
+again  move  for  the current side, change sides, and prompt
+you for what to do next.
+
+If you find yourself continually using a set of commands  to
+configure crafty to play as you want, you can put these com-
+mands in a startup file called .craftyrc (Unix) or crafty.rc
+(DOS/Windows).   The  format  for this file is just like you
+would type the commands at the keyboard, with  the  require-
+ment that the last line of the file must be "exit" on a line
+by itself.  Using this, each time you start Crafty, it  will
+
+
+
+
+
+
+
+
+
+
+
+
+
+first  execute the commands from this file before it prompts
+you for input.
+
+While Crafty is running, you can control what  it  displays,
+but  here's a couple of samples to explain what it is saying
+and why:
+
+           depth   time   score    variation (1)
+            book moves {d4, c3, Nc3, d3, b3, c4, g3, b4, Be2, Bb5}
+            book   0.0s     70%    d4
+
+White(3): d4
+            time used:   0.01
+
+This is the normal output for those cases where Crafty is in
+book.   The book moves line gives the set of book moves that
+made the first selection cut (see the book selection  expla-
+nation  given  later), followed by the move actually played,
+in this case d4.
+
+If Crafty is out of book, then  the  output  looks  somewhat
+different as given below:
+
+   depth   time   score    variation (1)
+     4->   0.81    2.09    6. dxe4 Bxe4 7. Rad8 Qf2 8. Qb5
+     5      1.37    2.41    6. dxe4 Bxe4 7. Ne5 Qf4 8. Bxe4+
+Qxe4 9. f5
+     5->   1.88    2.41    6. dxe4 Bxe4 7. Ne5 Qf4 8.  Bxe4+
+Qxe4 9. f5
+     6     7.38      --    6. dxe4
+     6     11.90     1.97    6. dxe4 Bxe4 7. Rab8 Qf2 8. Qc7
+Nc5 9. Qe5
+     6    12.92      ++    6. Ne5
+     6    13.71    2.23    6. Ne5 Qg2 7. Ng6 h5 8. Nh4 Qg4
+     6->  15.59    2.23    6. Ne5 Qg2 7. Ng6 h5 8. Nh4 Qg4
+   time: 15.60  cpu:99%  mat:1  n:246565  nps:15927
+   ext-> checks:4706 recaps:1336 pawns:0 1rep:301
+   nodes  full:45951  quiescence:200614  evals:104657
+   endgame tablebase-> probes done: 0  successful: 0
+
+Let's take this stuff one line at a time.  Lines  that  have
+something like 4-> in the depth column are printed when that
+iteration (depth) is  completely  finished.   The  time  and
+score  columns  should  be obvious as to their meaning as is
+the PV, the sequence of moves that led to this  score.   One
+note  about  the  "score"  column.  As of version 18, Crafty
+displays the score with + values good for  white,  -  values
+good  for  black,  no matter which side it is playing in the
+game.  All output now follows this convention, from playing,
+to  analysis  mode,  to  annotating  your games, to whisper-
+ing/kibitzing on the chess servers, and so forth.   This  is
+unlike  other  engines,  but  once you get used to it, it is
+much less confusing when you remember that  negative  scores
+
+
+
+
+
+
+
+
+
+
+
+
+
+are good for black and bad for white, and vice-versa.
+
+the  line that has -- in the score column means that when we
+started depth 6, dxe4 turned out to be worse than we thought
+(notice  score  dropped  from 2.411 last search to 1.972 for
+this move this search.)  To resolve this, Crafty lowers  the
+lower  search bound (alpha) and re-searches the move to find
+the score.  The line with ++ means that this move  (Ne5)  is
+better than the best move so far, so Crafty raises the upper
+search bound (beta) and re-searches this move  to  find  the
+new score.
+
+the  first line of statistics gives the total time taken for
+this search, the cpu percentage which should stay at 98-100%
+unless your machine is heavily loaded or unless Crafty is in
+an endgame that is  having  lots  of  contact  with  endgame
+databases.  If this drops below 98%, it means that Crafty is
+not getting full CPU usage and will be playing  weaker  than
+normal.   The mat:1 is simply the true material score, since
+Crafty's positional scores are often larger than a pawn.
+
+               Alphabetic Listing of Commands
+               ------------------------------
+
+1.  alarm on|off  This command is used to  control  Crafty's
+"beep"  after  it  makes a move.  Turning this off will make
+Crafty "quiet" when it plays, but also makes it easy to miss
+a  move  if  you  are  using crafty to play in a tournament.
+This is primarily designed to make Crafty  tolerable  during
+late night matches.
+
+2.  analyze  This command puts crafty into analyze mode.  In
+this mode, Crafty starts computing for whichever side is  on
+move,  and  it  continues computing and showing its analysis
+until a move is entered.  This move is made, Crafty  changes
+sides,  and  starts thinking and printing analysis all over,
+but for the other side now.
+
+This command is useful to play through a game,  because  you
+get  instant  feedback  when you try a move.  If you want to
+try a different move from the one you just entered, use  the
+"back"  command  to  back  up one move, or use "back <n>" to
+back up <n> moves.  Note that one move is a single move  for
+the  last  player, not a move for both sides.  To unmake the
+most recent 2 moves (one for black, one for white) use "back
+2".
+
+3.    annotate|annotateh  <filename>  <colors|name>  <moves>
+<margin> <time> This command is used to annotate (make  com-
+ments in) a game that has already been played.
+
+The annotate command produces a file with the .can extension
+added to the original name.  This  file  will  contain  pure
+
+
+
+
+
+
+
+
+
+
+
+
+
+ascii  information  from  the  annotation pass.  "annotateh"
+produces an HTML file instead (with  the  .html  extension).
+This  includes  the  normal  output,  plus  a nice bitmapped
+graphical board display for every position where crafty  had
+'something to say'.
+
+<filename>  is  the name of the file that has the game moves
+stored  in  it.   This  should  be  a  PGN-compatible  file,
+although  Crafty  can  read nearly any file with chess moves
+and convert it to pgn using the "read" and  "savegame"  com-
+mands to perform the conversion.
+
+<colors|name>  indicates  which  side  Crafty will annotate.
+The valid choices are w, b, and wb/bw for white only,  black
+only,  and  both, respectively.  Crafty will search and pro-
+duce results for the indicated color only, making moves  for
+the other side silently as they are read in.
+
+Alternatively,  you can specify the player's name (useful if
+you want to annotate several of your own games in one  large
+pgn file, for example, and you alternated colors so that you
+can't pick the right one easily).  Crafty will  then  figure
+out  which side to annotate for in each game.  Note that the
+name is case-sensitive, but that you only have  to  enter  a
+string  that is unique in the name field.  IE if one name is
+"Anatoly Karpov" and the other is "unknown" then  specifying
+Karpov  as  the  name  would  be  sufficient.   If  the same
+'string' appears in both names, Crafty will complain.
+
+<moves> indicates the moves that should  be  annotated.   If
+this  is  a  single  integer, annotation starts at this move
+number (for the color given above) and proceeds for the rest
+of  the  game.   If  a range is given, as (20-33), then only
+moves 20-33 inclusive are annotated.  To annotate  the  com-
+plete game, you can use 1-999.
+
+<margin> gives a score "window" that controls whether Crafty
+will produce comments (see below).  The larger  this  number
+this  number,  the fewer annotations Crafty will produce.  A
+negative number will result in an annotation for every  move
+selected.
+
+<time> indicates the time limit for each search.  Since each
+move selected requires two searches, you can take the number
+of  moves,  double  this  number  and  multiply by <time> to
+determine how long the annotation process will  take.   This
+time is in seconds.
+
+How it works.  Suppose you use the command "annotate game1 w
+1-999 1.000 30" This asks Crafty to read the  file  "game1",
+and  annotate the white moves for the entire game.  The mar-
+gin is 1 pawn and the search time limit is 30 seconds.   The
+output  for the annotate command is found in <filename>.can,
+
+
+
+
+
+
+
+
+
+
+
+
+
+in this case this is game1.can.
+
+Crafty first searches the move actually played in  the  game
+to  determine  the  score  for it.  Crafty then searches the
+same position, but tries all legal moves.  If the score  for
+the best move found in this search is greater than the score
+for the move actually played plus the margin, then a comment
+is  added  to  the  output  file.  This output file is quite
+short, with all the game moves (plus any  PGN  tags  in  the
+original,  for  identification purposes) plus the brief com-
+ments.  An annotation looks like this:
+
+{real_value (depth:best_value PV moves)}
+
+real_value is the score for the move actually played.  depth
+is  the  depth Crafty searched to produce the best_value and
+PV for what it thinks is the best sequence of moves for both
+sides.   If you set <margin> to 1.000, you are asking Crafty
+to only annotate moves that either lost a pawn or  more,  or
+moves  that  failed to win a pawn or more.  If you set <mar-
+gin> to .300, you are asking for annotations  for  any  move
+that  makes  the  score  drop  about 1/3 of a pawn below the
+value for the best move Crafty found.
+
+If you have other moves you would like to see analyzed  dur-
+ing  this  annotate process, at the point where the move can
+be played, insert it into the PGN file as an  analysis  com-
+ment,  surrounded  by () or {} characters.  Crafty will pro-
+duce analysis for this move as well.  If more than one  move
+appears  inside  a  single set of delimiters, only the first
+will be analyzed.  To force Crafty to analyze more than  one
+move,  enter them like this:  (move1) (move2) as though they
+were two separate comments.
+
+4.  ANSI on|off  This command is used to control whether  or
+not  Crafty attempts to display its move in reverse video or
+not.  For PC's, Linux, and most Unix boxes, this works fine.
+Should you find yourself playing crafty via a dumb terminal,
+this might hose the terminal and interfere with your ability
+to  see  or  input  moves.   If  moves  are not displayed in
+reverse video, it's probably wise to turn this off to  avoid
+hanging the terminal you are using.
+
+5.   black|white   This  command  simply toggles the side on
+move.  if it is white to move, and you enter white,  nothing
+happens.   If  it is white to move and you enter black, then
+it becomes blacks turn to move  immediately  from  the  same
+position.  Used only infrequently.
+
+6.  book (see the book explanation near the end of this doc-
+ument for a full explanation of this command  and  its  many
+options.)   Note  that  there are special commands available
+(*only*   on   the    command    line,    *not*    in    the
+
+
+
+
+
+
+
+
+
+
+
+
+
+crafty.rc/.craftyrc  files)  to  direct  crafty  to specific
+directories for the book files (bookpath=/a/b/c), the table-
+base   files   (tbpath=/i/j/k)   and  the  log  files  (log-
+path=/x/y/z).  Note that these commands can *only*  be  used
+on  the  command  line, because they must be executed before
+the  engine   is   initialized.    Putting   them   in   the
+crafty.rc/.craftyrc file will produce error messages without
+affecting how the files are opened.
+
+If you need to specify multiple  directories  (tbpath  only)
+you  may  do  so  by using "tbpath=path1:path2:path3:etc" or
+else       use       the       more        Unix-        like
+"tbpath=(path1:path2:path3:etc)"  instead.   The  paths  are
+separated by ":" (colon) characters and everything is  case-
+sensitive  as  usual.   For dos/windows users, the separator
+can be a semi-color (;) or a comma(,)  to  avoid  the  drive
+designation ambiguity.
+
+7.   cache=N   This  command is used to alter the cache size
+used for endgame database probes.  N can be a  simple  inte-
+ger,  representing  the  number of bytes to use or it can be
+specified as nK or nM representing n * 1024  bytes  or  n  *
+1024  *  1024  bytes.   This  should  be in multiples of the
+database "chunk" size, which might vary.  Using the nM  form
+guarantees that you will have a reasonable number.
+
+8.    clock  <ctime>  <otime>   This  command  is  primarily
+intended for use when Crafty is  playing  in  a  tournament,
+such  as the WMCCC or WCCC events.  If the operator is some-
+what slow in entering moves, or forgets to  stop  the  clock
+after making a move for Crafty, the chess clock for the game
+will drift from the values that Crafty maintains internally.
+<ctime>  is the time (in minutes or hh:mm format) crafty has
+left until the next time control, and <otime> is  the  oppo-
+nent's  remaining  clock  time.  This command can be used at
+any time, but will only affect the  time  per  move  *after*
+crafty makes the current move and starts to think about what
+the opponent might do next.
+
+9.  computer  This command usually  comes  from  xboard/win-
+board,  but  can  be  used  at any time to tell Crafty it is
+playing a computer.  This will prevent some things from hap-
+pening, such as a draw score that varies, as well as adjust-
+ing the book selection code to be more selective in what  it
+plays.
+
+10.   display   this  command  is  used  to display the game
+board.  This board is displayed using the ICS style #1  type
+of  ASCII  display,  with  white always at the bottom of the
+screen, black at the top.  Very  unusable  to  play  a  game
+with,  but  good  to verify a position after it has been set
+up.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+This  command  is  also  used   to   display   the   various
+piece/square  tables,  by  typing  "display  <piece>"  where
+<piece> is replaced by pawn, knight, bishop, rook, queen  or
+king.   The board is oriented in the same way as the display
+board with a one-to-one correspondence between the  squares.
+Perhaps  useful  for  curiosity,  but not for anything else.
+These values can not be modified by the user.
+
+The final version of this command is used  to  control  what
+kind of output you will see when crafty runs.  Currently the
+following options are available.
+
+       display time:  this  will  make  Crafty  display  the
+     amount of time each side takes after making a move.
+
+       display  changes:   this will make Crafty display the
+     PV each time it changes during  the  search,  including
+     when a move fails high or becomes a new best move.
+
+     display  variation:   this will make Crafty display the
+     PV at the end of each iteration, but it will only  show
+     the  best  PV  for the entire iteration, not all of the
+     changes.
+
+     display stats:  this enables  basic  search  statistics
+     output including time, nodes and so forth.
+
+     display  extstats:   this enables extended search stats
+     including  the  hashing  statistics,  search  extension
+     statistics and so forth.
+
+     display movenum: causes all PV output to have move num-
+     bers embedded in them to make the PV possibly easier to
+     read.   This  causes the PV to look like this:  12. ...
+     Nxe4 13. Bxe4 h6 rather than simply Nxe4 Bxe4 h6.  This
+     is very helpful when playing on a server and whispering
+     or kibitzing analysis.  It will  also  be  useful  when
+     crafty  is  run  from  within a database program as the
+     move numbers will sync up with the actual game.
+
+     display moves:  will display each root move  as  it  is
+     searched,  along  with  updating the search time at the
+     bottom of the screen, so you can see what move is  cur-
+     rently being analyzed.
+
+     display general:  will display general information mes-
+     sages whenever Crafty wants to tell you  something  (ie
+     "clearing  hash tables" or other such things like "Mate
+     in n moves."
+
+If you put a "no" in front of any  of  these  options,  that
+will disable that particular type of output.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+11.   draw  offers Crafty a draw.  It generally will look at
+the value returned by the last search, and compare  it  with
+the  value returned by an internal function DrawScore().  If
+the search value is not above this result, then Crafty  will
+accept the draw.  If the search value is above the theoreti-
+cal value for a draw, Crafty will decline  the  draw.   Note
+that  crafty  will  offer  draws based on internal analysis.
+When it offers a draw, you can respond with "draw"  although
+the game does not really end until you exit Crafty.
+
+12.  drawscore N sets the draw score (or contempt factor) to
+N.  If you want crafty to avoid draws, set  this  number  to
+something  that  is negative.  IE -50 says that a repetition
+(draw) is the same as being 1/2 pawn down.   Setting  it  to
++100  will  make it try very hard to draw because that looks
+like it is winning a pawn when it does so.  Note  that  this
+is dangerous (either way) as a -50 in a king and pawn ending
+is very likely dead lost...  and a repetition is better.
+
+13.  echo <text>  This command is  normally  used  inside  a
+command file that you are going to use to "feed" crafty some
+positions for analysis or whatever.  Since crafty depends on
+the  operating  system  to  echo commands as they are typed,
+commands read in from a file are  "invisible."   This  gives
+you  the ability to insert commands into such a file so that
+crafty displays a message on the screen to give you an  idea
+of where it is in processing the file.
+
+14.   edit   This command has been "cloned" from GnuChess to
+provide an interface with Xboard.  After entering the "edit"
+command,   you   are   in   "edit.white"   mode,  where  any
+piece/square combination you enter will  add  the  indicated
+white  piece on the given square.  Piece/squares are entered
+as "qa3", or "bc4" for example.  This puts a white queen  on
+a3  and  a  white  bishop  on c4.  Once all white pieces are
+entered, typing a "c" changes  to  "edit.black"  mode  where
+piece/square  combinations now place black pieces.  Typing a
+"." character exits edit mode.   To  clear  the  board  ini-
+tially, you use the "#" character.
+
+Here's  a  sample  to set up the original starting position,
+after white has played 1. e4, but no other moves  have  been
+played.
+
+  edit
+  #
+  ra1 nb1 bc1 qd1 ke1 bf1 ng1 rh1
+  pa2 pb2 pc2 pd2 pe4 pf2 pg2 ph2
+  c
+  ra8 nb8 bc8 qd8 ke8 bf8 ng8 rh8
+  pa7 pb7 pc7 pd7 pe7 pf7 pg7 ph7
+  .
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Note  that  input  is  free  form,  so  piece/squares can be
+entered one per line or all on one line.  Ditto for  the  #,
+c, and . special characters.  Note also that there is no way
+to enter castling status here.  It is far better to use  the
+"setboard"  command  which uses a FEN-like syntax and allows
+you to set both castling and enpassant status.
+
+15.  egtb   This  command  enables  the  endgame  databases.
+Crafty  will  use  the  "tbpath"  directory (if provided) to
+locate and register all of  the  databases  you  have  down-
+loaded.  It will report the largest class it found, as in "5
+piece tablebase files found" if you downloaded at least  one
+5-piece  file.  If you use this command to enable databases,
+you should also consider using the "cache" command to  spec-
+ify the egtb cache size.
+
+16.   end|quit  These commands are used to terminate crafty.
+Note that you can resume a  game  later  without  having  to
+replay  the  moves,  by starting Crafty using the "crafty c"
+command.  It will immediately read in the moves for the last
+game,  although  you  will have to set the time controls and
+clock time remaining yourself.
+
+17.  evaluation option <value>  This command is used to mod-
+ify the evaluation scores.
+
+The  option "asymmetry" is used to make crafty evaluate king
+safety differently for each side.  "evaluation asymmetry 25"
+will  increase the king safety scores for the opponent only,
+meaning it will pay less attention to its  own  king  safety
+than  to  that of its opponent.  This will make it play more
+aggressively.  "evaluation asymmetry -25"  will  reduce  the
+king  safety  scores  for for the opponent by 25%, making it
+care more about its own king safety than that of  its  oppo-
+nent.  This will make it play more defensively.
+
+The  "bscale"  option  will  adjust  the  scores for blocked
+pawns.  The default value is 100.  Increasing this will tend
+to  make  Crafty  dislike blocked pawn positions more, which
+will lead to more  open  positions.   Note  that  this  only
+affects  moves  _after_  the opening book has been followed,
+which means that the position might be  blocked  before  the
+evaluation term has a chance to affect the game.
+
+The "kscale" option will adjust all king safety scores based
+on the 'value' entered.  For example, "evaluation kscale 50"
+will  reduce  all  king safety scores to 50% of their normal
+value.  "evaluation  kscale  133"  will  increase  all  king
+safety scores to 133% of their normal values.
+
+The  option  "tropism" is used to scale king tropism scores.
+This will attract pieces toward kings.  A value of 100 means
+no  change.   other values are treated as a percentage (like
+
+
+
+
+
+
+
+
+
+
+
+
+
+scale) to increase (>  100)  or  decrease  (<100)  the  king
+tropism scores.
+
+When you use this command, you will see something like this:
+
+modified king-safety values:
+white:   0   4  16  26  39  45  58  77  87  90  93  96 100 103 106 109
+       112 116 119 122 125 128 128 128 128 128 128 128 128 128 128 128
+
+black:   0   5  20  32  48  56  72  96 108 112 116 120 124 128 132 136
+       140 144 148 152 156 160 160 160 160 160 160 160 160 160 160 160
+
+Those values represent the  king-safety  evaluation  as  the
+king  gets  more  and more exposed.  This is always based on
+the fast that "crafty" will be the side  on  move  when  the
+search  starts.  In the above, it was white's move when this
+was typed, meaning that it appears that crafty will be play-
+ing  black.   Notice  that  white's  king safety numbers are
+scaled by 20% to make it slightly more  cautious  about  its
+own king.  If you type "go" in this position, the scores get
+reversed as Crafty's scores are always left alone (with  the
+asymmetry  option) and the opponent's scores are scaled down
+as indicated.
+
+You will see similar numbers (but not black and white  sets)
+that  represent the actual scores produced for king tropism.
+Note that pieces interact to choose which  element  of  this
+vector is used, but in general, the more pieces are close to
+the king, the larger the element from this array.
+
+The "pscale" option is used to scale normal  pawn  structure
+scoring  in  the same way as the other scaling options.  100
+is the default.  Values less than 100 reduce this term, val-
+ues over 100 inflate it.
+
+The "ppscale" option is used to scale some passed pawn scor-
+ing in the same way as the other scaling  options.   100  is
+the  default.  Values less than 100 reduce this term, values
+over 100 inflate it.  This  mainly  effects  outside  passed
+pawns/protected  passed pawns.  The normal pawn scoring com-
+putes the value of a passed pawn.  This term is then used to
+scale  those  terms  that modify this value further, such as
+two connected passed pawns on the 6th, or a passed pawn with
+the king supporting it in an endgame.
+
+18.  extensions type value
+
+This  command is used to control the extension depth for the
+various extensions done in Crafty's search.  The  extensions
+are  set  as  decimel numbers that represent plies (or frac-
+tions of plies) to extend for each particular reason.   Most
+default  to  1.0  and  .75, but any value can be used.  Note
+that value > 1.0 are _very_ dangerous as they can cause  the
+
+
+
+
+
+
+
+
+
+
+
+
+
+search  to  become non-terminating (crafty will stop when it
+runs out of time for the move, but it might not be  able  to
+get anything useful from such a search).
+
+These  extensions  are presently limited to a maximum of one
+ply of extensions at any point in the tree.   IE  no  matter
+what you set these values to, they can not exceed one ply at
+present.
+
+incheck  This is the amount to extend when the side on  move
+makes  a  move that leaves the opponent in check.  Note that
+Crafty extends on the ply where the check is played, not  on
+the next ply where the opposite side is in check.
+
+onerep   This  is  the one-reply-to-check extensions, and is
+done at the point where one side is in check and has exactly
+one legal move to escape from the check.
+
+pushpp   This  is the extension used for certain passed pawn
+pushes in the endgame.
+
+recapture  This is the recapture extension, and  is  applied
+when  the current move recaptures an equal-valued piece that
+made a capture at the previous ply.  IE BxN, PxB.  Note that
+this  can  only  be applied once for every two plies so that
+BxN, BxB, NxB, NxN won't look like three recaptures.
+
+mate  This is the mate threat extensions and is applied when
+a  null  move  search returns -MATED, which means that doing
+nothing gets the side on move mated.  The opponent must have
+some sort of serious mate threat in such a position.
+
+19.   flag  on|off   This command is used to force crafty to
+end a game where the opponent runs out  of  time  with  win-
+board/xboard (on) or to ignore this (off) if desired.
+
+20.   force  [move]  This command is used to force Crafty to
+play a move that is different from the one chosen and played
+by  the  tree search.  If [move] is given, and it is a legal
+move, Crafty will retract its last move and make  this  move
+instead.   It  does  not  change  the side on move, but does
+change the position of course.   If  [move]  is  not  given,
+Crafty will prompt you for a move to make.
+
+21.   help  This command displays multiple pages of one-line
+help, one command per line.  If a  line  ends  with  [help],
+then  you  can  use help followed by the specific command to
+get detailed help.
+
+22.  history  This command displays the history in a  verti-
+cal  column  with  one  move for white and one per black per
+line.  There are other ways  to  display  the  current  game
+moves  and  also  to  save  them in files that are explained
+
+
+
+
+
+
+
+
+
+
+
+
+
+later.
+
+23.  hash=x and hashp=x  These commands are used  to  adjust
+the  size  of  the hash tables in Crafty.  hash modifies the
+size of the transposition/refutation table, while hashp mod-
+ifies the size of the pawn structure/king safety hash table.
+The sizes may be entered as one of the following  two  types
+of  values: nnnK where nnn is an integer indicating how many
+Kbytes Crafty should use for this hash table; nnnM where nnn
+is  an integer indicating how many Mbytes Crafty should use.
+
+The transposition/Refutation table is the most  critical  of
+the two, because it directly affects search efficiency, par-
+ticularly in the endgame.  For this reason  this  should  be
+maximized.   The  most effective size for this hash table is
+3/4 of your available memory.  If you don't know how to fig-
+ure  this  out,  but know that you have 16 megs for example,
+they you can say hash=16M and crafty will round that down to
+12M,  which is 3/4 of a power of two size.  If you study the
+sizes that are possible, you will find  3M,  6M,  12M,  24M,
+48M,  and  so forth.  Anything up to, but not including, the
+next size will be rounded  down  to  the  next  lower  size.
+hashp  should  be  set to approximately 1/2 of what is left.
+For example, the P6 Crafty runs on when playing on ICC often
+uses  hash=48M and hashp=8M.  The only thing to watch for is
+that if you make this too large, particularly under windows,
+performance  will  suffer  badly because of paging I/O over-
+head.  When Crafty is searching in a normal (non-book,  non-
+endgame  database)  position, the disk light should *not* be
+on, indicating lots of I/O.
+
+There is no danger in making this table too large,  although
+you  have to watch out because if Crafty barely fits in mem-
+ory, doing something else on the machine can cause Crafty to
+be  swapped  out  completely  or partially, depending on the
+operating system you are using.  If you are going to use the
+machine  for  anything  else  while Crafty is running, it is
+better to "pretend" that the machine only  has  1/2  of  the
+memory  it actually does when computing the size of the hash
+tables you want to use.
+
+24.  import <filename> [clear]   This  command  is  used  to
+import any sort of learning data that Crafty supports, which
+currently includes book learning data and position  learning
+data.   This  command  reads  the appropriate <filename> and
+imports that learned data, just as though Crafty had learned
+it  by playing the games.  The [clear] option, if specified,
+caused all old learned results  to  be  cleared  before  the
+import  operation,  otherwise  the  imported  data is simply
+added to what is already present.
+
+25.  input <filename>  This command is used to redirect  the
+console  input  I/O  stream  from  the  keyboard  to a file.
+
+
+
+
+
+
+
+
+
+
+
+
+
+Crafty will then read commands from this file,  rather  than
+from the keyboard, and execute them just as though they were
+typed in.  Such a command file *must* be  terminated  by  an
+"exit"  command (no quotes) as the last command in the file.
+This reverts the input stream  back  to  the  keyboard,  and
+prompts you for another command or move.
+
+This  command  might  be used to configure crafty for a spe-
+cific time control, by putting the appropriate time  control
+commands  in  the file, or to customize the hash table sizes
+as needed.
+
+26.  info  This command is used to display information about
+Crafty  and  the current game.  Such things as the time con-
+trol, the time left on the clocks and other  information  is
+shown.
+
+27.   learn  n  controls  the learning facilities in crafty.
+Currently this is a 3-bit boolean switch,  bit 1 (001)  con-
+trols book learning, bit 2 (010) controls position learning,
+and bit 3 (100) controls result learning.  learn=0  disables
+all  learning,  learn=1  enables book learning only, learn=2
+enables position learning only, and learn=4  enables  result
+learning.   Add the values together to turn on more than one
+type of learning (default=7 to enable everything).
+
+28.  level <m> <t> <inc>  This command  was  taken  directly
+from  GnuChess  so  that the Xboard/WinBoard interface would
+interface with Crafty.  There are other better ways  to  set
+the  time, but this one is well-known.  The three parameters
+are <m> (number of moves in the game)  <t> initial  time  on
+the clock.  After <m> moves are made, this amount of time is
+added to the clock again.  <inc> is the Fischer-Clock incre-
+ment  that is added back to each clock after a move is made.
+It may be zero for a non-increment game.
+
+Examples:
+
+level 0 5 0            (ICS 5 0 game)
+level 0 5 3            (ICS 5 3 game)
+level 0 15 30          (ICS 15 30 game)
+
+29.  list GM|IM|C|AK|S  +name [+name ...] -name [-name  ...]
+This command is used to maintain the internal "lists" Crafty
+uses to auto-tune itself when playing  on  a  chess  server.
+There  are  three lists, GM, IM and C.  If Crafty's opponent
+is in any of these lists, Crafty adjusts  internal  controls
+that  affect  how/when  it  resigns or offers draws, and how
+randomly it will choose moves from the  opening  book.   For
+example, Crafty resigns much sooner against a GM, because it
+assumes he knows how to win a rook-up ending, regardless  of
+how  much  time  is  left.   By the same token, when playing
+against computers, Crafty will always assume that a draw  is
+
+
+
+
+
+
+
+
+
+
+
+
+
+0.000, so that it doesn't wreck its position trying to avoid
+repeating a position.
+
+The AK list will automatically  kibitz  scores/PV's  if  the
+opponent  is  in this list.  The S list will turn on special
+scoring for opponents in this list.  The only current member
+is "mercilous".
+
+The  syntax  +name1  +name2 simply adds these players to the
+specified list.  To remove a name, use -name1  -name2.   You
+can  use  one  command per name to remove or add, or you can
+use one command to add and remove multiple names.  Note that
+all names must be entered in lowercase characters, using any
+uppercase characters will break the matching algorithm.
+
+30.  log off|on|<n>  This command is used  to  disable  log-
+ging.  The default is log on, which causes crafty to produce
+a new log.nnn file for each game played.  If you are running
+Crafty  on  a  server, you might use log off, which disables
+creating these files as well as the game.nnn files  used  to
+restart  a  game  after you exit crafty and come back later.
+If you use the form "log n" crafty will simply  display  the
+last  n  lines  of the log on the screen.  If you use "log n
+file" crafty will copy the last n lines of the log to "file"
+which could be your hard drive, or a floppy.
+
+Note  that  if  you  run with log off, you will be unable to
+find out what Crafty was thinking about since  there  is  no
+other  record  of  the game.  You will always see a game.001
+because as crafty plays a game, this contains all  the  real
+moves  played so far so that you can back up if needed.  you
+will also see a log.001 file, but it will be empty.
+
+31.  ls <filename> will list all the files  that  match  the
+filename  wildcard  (the  wildcards depend on the system you
+are using, but generally *, ? will work fine.  you can  also
+supply  path information in the filename if you want to list
+the contents of a different directory.  Just  use  the  same
+syntax  you would if you were using "ls" under unix or "dir"
+under windows.
+
+32.  mode tournament|normal  This command is primarily  used
+to  put Crafty into "tournament" mode, which is intended for
+use when Crafty is playing in  computer  chess  events.   It
+accomplishes two things:  (1) makes all draws return a score
+of 0.000, and (2) makes crafty issue a  message  after  each
+move  showing  the internal chess clock time, and requesting
+that that operator check and  adjust  as  needed  using  the
+"clock"  command.   This  primarily makes Crafty comply with
+computer chess rules that say the operator can't do anything
+not specifically requested by the program.
+
+33.   name  <name>   This  command  is  an ICS-play specific
+
+
+
+
+
+
+
+
+
+
+
+
+
+command.  Xboard/WinBoard uses this to inform Crafty of  the
+opponent's  name.   Crafty uses the name, and looks it up in
+its GM/IM/C lists, and if found, adjusts itself accordingly.
+This is not used by the PGN code and this will not cause the
+players <name> to show up in the PGN tag section.
+
+34.  new  This command wipes everything  out  and  starts  a
+brand  new  game.  It closes the old log-file and game-file,
+and opens the next sequential numbered file.  It also resets
+the  game to the beginning and prepares to start a brand new
+game.  This was added for Xboard,  but  it  turns  out  that
+Xboard  does not use this, rather it starts Crafty fresh for
+each new game by first terminating the old copy then  start-
+ing  a  new one.  Not nearly as efficient as using "new" but
+likely safer it a program can't be sure of resetting  every-
+thing back to the initial state.
+
+35.   noise  <n>   This  command  sets  the "noise" level in
+Crafty.  Basically, until  <n>  nodes  have  been  searched,
+crafty will be silent and not display analysis.
+
+This  is  useful  in two ways.  First, in end-games, 20+ ply
+searches are not uncommon, and the search analysis  for  the
+first  few  plies arrives so quickly that it is distracting.
+Second, when observing games (new  interface  only)  on  ICS
+servers,  this  can  be used to avoid having Crafty generate
+too many analysis kibitzes.  A value of  100000  will  basi-
+cally  shut  off any output for the first second or so (on a
+P6/200).  Similarly, 1000000 will eliminate any  output  for
+about  the  first  10  seconds.  When watching and kibitzing
+games like the World Championship games on ICC, I  generally
+use  5000000,  which is almost one minute of silence so that
+the first PV it kibitzes is a pretty deep search.
+
+noise 0 will cause *all* analysis to be displayed, which  on
+a  fast machine causes no problems.  On a slower machine, or
+over a slow phone connection, this might cause a big  commu-
+nication  backlog.   The  default is roughly one second on a
+P6/200 (100000) but can be modified by this command.
+
+36.  operator <n>  Another command  intended  for  use  when
+Crafty  is  playing  in  a  tournament, operated by a human.
+This tells crafty to "hide" <n> minutes of time and not  use
+them.   This  time is basically allocated to the operator to
+make up for the time it takes to type in moves  and/or  cor-
+rect mistakes.  At the WMCCC events, the normal value we use
+is 5.  Playing on a server, this is not needed, as it is not
+needed if you are playing Crafty yourself.
+
+37.   perf   This  command  is  primarily used in optimizing
+Crafty, or to test the speed of the move generator and Make-
+Move()/UnMakeMove() on different platforms.  It produces two
+results, the moves it can generate per second, and the moves
+
+
+
+
+
+
+
+
+
+
+
+
+
+is  can  generate and make/unmake per second.  While this is
+not  a  perfect  performance  indicator,  it  does  give  an
+"approximation"  for how fast Crafty might run.  In general,
+the higher the numbers, the better the  program  will  play,
+although  machines are certainly different.  It's not uncom-
+mon to find a machine that searches slower than another, but
+has a higher "perf" value.
+
+38.   perft  <depth>  This command is generally used to con-
+firm that the move generator and bitmap operators are  work-
+ing  properly.   It  simply  takes the current position, and
+generates/makes/unmakes moves and counts  them.   Many  pro-
+grams  use this from a "standard" position to make sure that
+their move generator does not miss generating odd moves like
+enpassant/promotions   and   also   to   confirm   that  the
+make/unmake code correctly updates the  board  so  that  the
+totals  remain  constant  across different machines and pro-
+grams, since there is no  alpha/beta  or  evaluation  things
+done.   if  <depth>  is  greater than 5 or 6, it will take a
+*long* time, since this is basically a minimax tree  traver-
+sal  that  will visit *every* node within the <depth> search
+horizon.
+
+39.  pgn <tag> <value>  This command  is  used  to  set  the
+usual  PGN  tags  to meaningful values.  The recognized tags
+are Event, Site, Round, Date, White, WhiteElo, Black, Black-
+Elo,  and  Result,  and  the tags *are* case sensitive.  The
+<value> can be any valid input and blanks and special  char-
+acters are allowed.  Note that the date is clearly specified
+in the PGN standard and must be yyyy.mm.dd with no variance.
+Valid  results are 1-0 (white won), 0-1 (black won), 1/2-1/2
+(drawn) and * (unknown).  Some examples:
+
+pgn Event 14th World MicroComputer Chess Championship
+pgn Date  1996.10.8
+pgn Site  Jakarta, Indonesia
+pgn Round 1
+pgn White Crafty
+pgn WhiteElo 2400
+pgn Black assassin
+pgn BlackElo 2400
+pgn Result 1-0
+
+Setting these values will result in a proper PGN  file  when
+using the savegame command.  Note that if you use the "read"
+command to input a PGN game, these values will be  extracted
+from that game if they are given.
+
+40.  ponder off|on|<move>  This command serves two purposes.
+First, it can be used to disable (off) or enable (on) think-
+ing  on the opponent's time (or pondering as it is called in
+many programs including Crafty.)  Turning it off will weaken
+Crafty  since it will not use any machine time while waiting
+
+
+
+
+
+
+
+
+
+
+
+
+
+on the opponent to move.  It is sometimes  useful,  however,
+when   playing  Crafty  against  another  computer  and  the
+machines are not equal.  If crafty is on a  faster  machine,
+and  you  attempt  to adjust for this by giving the opponent
+more time than Crafty, it doesn't work  quite  as  expected,
+because  while the opponent is thinking, so is Crafty, which
+lets it use the extra opponent time in  an  unexpected  way.
+In  such  a  case,  it's best to stop pondering in both pro-
+grams.
+
+If <move> is given, it directs Crafty to use that <move>  to
+ponder,  rather than the one from the previous search.  Most
+commonly this is used to set the right move to ponder  after
+Crafty has been stopped and then restarted, assuming that it
+is the opponent's turn to move when  this  happens.   Other-
+wise,  it is probably better to not try to influence things,
+although if you are watching and suddenly wonder "what would
+Crafty  do  if the opponent plays move 'X'?", you can answer
+this by simply typing "ponder X" and then watching the anal-
+ysis.  You should reset the correct ponder move after you do
+this of course.
+
+41.  reset <n>  This command lets you back up in the current
+game  to  any  move  of your choice.  reset <n> backs up the
+game to move <n> with the same side on move.  If you want to
+first  change the side to move, use the white/black command,
+then use the reset command to back up  to  the  right  move.
+Note that you can also go forward as well, just so there are
+moves in the current game history.
+
+42.  resign <n>  This command  sets  the  resign  threshold.
+When  running  on  ICC I typically use "resign 9" which will
+make crafty resign roughly five moves after the score  drops
+below  -9.000.   For IM's I change this to 6, and for GM's I
+often use 3, so that it will resign quicker and not  drag  a
+lost game out unnecessarily.
+
+43.   read/reada [<filename>]  This command will read input,
+and extract the chess moves and make  them  to  set  up  the
+position  at the end of the game.  It first resets the chess
+board to the initial position (read command only)  and  then
+extracts  the  PGN  tags  (if present) from the front of the
+input.  The rest of the input  is  parsed  for  chess  moves
+(comments  and  similar things are culled automatically) and
+the moves are made and added to the game history.  Once this
+is done, you can back up, go forward, or play from any point
+in the game.  If you specify a <filename> everything is read
+from  the  file,  otherwise it is read from the console key-
+board.
+
+The reada command reads moves, but appends them to the  cur-
+rent  game  history/  position  rather than resetting to the
+initial chess position.  This lets you read in a game,  then
+
+
+
+
+
+
+
+
+
+
+
+
+
+use reada to manually add some more moves to see the result-
+ing position.
+
+44.  savegame <filename>  This command is used to  save  the
+current  game  in  a  PGN-compliant  file  with the PGN tags
+included.  Note that the default TAG  values  might  not  be
+what  you  want  if you do not either use the pgn command to
+set them or else input  a  valid  PGN  file  with  the  tags
+already filled in.
+
+Be  aware  that  this command doesn't check the filename for
+legality since anything goes in UNIX.   In  DOS,  you  might
+produce  a bad filename with either too many characters, too
+many periods, or whatever, so be careful with the  name  you
+choose.   Note also that this file will be overwritten if it
+already exists, so be sure to choose a name that is not  the
+name  of a file that has something you consider important in
+it.
+
+45.  savepos <filename>  This command writes a  single  line
+into  <filename> in FEN-like notation.  This lets you save a
+position, and then come back later to  re-examine  it.   You
+would use the "in <filename>" command to input this file and
+set the position up.
+
+46.  search <move>  This command allows you to  specify  one
+particular move for the side on move, and then when you tell
+Crafty to search this position, this is the only  move  that
+will  be  searched.  This is used internally by the annotate
+command, but can be used to investigate one  specific  move.
+If the move is not the best move, a normal search won't show
+you why it is bad, but this will.  It is also  quite  a  bit
+faster  since  the  other  moves  in  the  position  are not
+searched at all.
+
+47.  settc <moves> <ctime> <otime>  This command is  primar-
+ily  used  in tournaments, and is an error-recovery command.
+If the machine crashes and corrupts the game  history  file,
+frequently the operator will have to simply set the position
+using the setboard command, and then use the  settc  command
+to  restore the time control values.  <moves> is moves until
+the next time control (from Crafty's perspective, be careful
+and  don't  look  at the opponent's moves to time control by
+accident.)  <ctime>  is  minutes  left  on  Crafty's  clock,
+<otime> is minutes left on the opponent's clock.
+
+48.   setboard  <FEN  input>   This command is used to set a
+chess position up for analysis and is the preferred  way  to
+do  this, rather than using the gnu EDIT interface.  It uses
+a classic Forsythe-like notation to encode the position  and
+also  has  provisions for castling status and enpassant cap-
+ture status.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+the standard piece codes p,n,b,r,q,k are used to denote  the
+type  of  piece  on  a  square, upper/lower case are used to
+indicate the color of  the  piece  (uppercase=white  pieces,
+lowercase=black pieces).
+
+the pieces are entered from the classic chess diagram's ori-
+entation of a8  being  the  upper-left-hand  corner  of  the
+board,  and  this  square  is entered first, followed by the
+remainder of the 8th rank left to right.  To indicate  empty
+squares,  use  a number between 1 and 8 to indicate how many
+adjacent squares are empty.  use a / to terminate each  rank
+after  all  of  the  pieces for that rank have been entered.
+Note that you do not have to account for all 8 squares on  a
+given rank, although many test suites do this for clarity.
+
+the following input will setup the board position that given
+below:
+
+      k2r/ppp////Q/5PPP/7K/ B
+
+this assumes that k represents a white king  and  -q  repre-
+sents a black queen.
+
+                      -k  *  * -r  *  *  *  *
+                      -p -p -p  *  *  *  *  *
+                       *  *  *  *  *  *  *  *
+                       *  *  *  *  *  *  *  *
+                       *  *  *  *  *  *  *  *
+                       q  *  *  *  *  *  *  *
+                       *  *  *  *  *  p  p  p
+                       *  *  *  *  *  *  *  k
+                                                                           *
+the field after the final "/" should be either  b  or  w  to
+indicate  which  side is "on move."  after this side-to-move
+field any of the following characters can appear to indicate
+the   following:   KQ:  white  can  castle  king-side/queen-
+side/both;  kq: same for black;  a1-h8: indicates the square
+occupied by a pawn that can be captured enpassant.
+
+49.   score   This command simply gives the positional score
+for the current position.  This score is  from  whites  per-
+spective,  so a + score is good for white, a - score is good
+for black.  Crafty also breaks the  score  down  into  major
+categories  (from  Evaluate())  to indicate things like pawn
+structure, piece evaluation, passed pawns, development,  and
+so forth.  Note that some of Crafty's evaluation is asymmet-
+ric, so that if you simply change sides with the white/black
+command  and then enter "score" again, you may get a differ-
+ent value.  This is *not* a bug.  :)
+
+50.  sd <n>  This command lets you specify a specific search
+depth  limit  that  Crafty  can  not  exceed.  It still pays
+attention to the clock, however, so often you will  use  the
+
+
+
+
+
+
+
+
+
+
+
+
+
+st  <n>  command  (below)  in  conjunction  with this if the
+search is going to take an extended amount of time.  <n>  is
+the  depth  (in  plies  or  1/2  moves) that the search must
+reach.  Note that if Crafty is pondering,  it  still  honors
+this  limit  and  will stop a ponder search after this depth
+has been completed as well.  This is *not* the way  to  make
+Crafty play weaker, although this will be covered in a later
+section of this document.
+
+51.  show <category>  This command forces Crafty to  display
+additional information about certain actions it takes.  Cur-
+rently the only <category> is "book" which will make  crafty
+display information about all the book moves it found in the
+database.  More is given about this information in the  BOOK
+section later in this file.
+
+52.   smpmt=n   This  command  is  used to set the number of
+threads to use on a machine with more  than  one  processor.
+For  optimal performance, "n" should be set to the number of
+processors you have, although using fewer  will  reduce  the
+load on your machine.  For this command to work, Crafty must
+have been compiled with SMP defined.  When compiled with SMP
+enabled,  mt=0 effectively disables the SMP code completely.
+
+This command also has two that are closely related.   smpmin
+and smpmax.  Both accept single numerical arguments.  smpmin
+is used to control the minimum tree depth required at a node
+for  it  to be eligible for parallel searching.  IE smpmin 2
+says don't split unless at least two more plies are left  to
+search  below  this  node.   smpmax sets the maximum for the
+same idea, is smpmax 10 says don't split  if  more  than  10
+plies are remaining below this node.
+
+53.   sn <n>  This command is similar to the sd command, but
+instead of setting a specific search depth, it sets a number
+of  nodes to search.  Once the search has searched this num-
+ber of nodes (+ maybe one more second of searching to  check
+the time) the search will exit.
+
+54.  st <n>  This command lets you specify a specific search
+time limit for Crafty.  Again, this is not the preferred way
+to  set  a time per move, because this limit is absolute and
+Crafty will never go over this limit, even if it  sees  that
+it  is  losing  or  getting mated.  Setting the time control
+with the usual "time" or "level" command is  *much*  better.
+<time>  is given in seconds, although it may also be entered
+as mm:ss if preferred.
+
+55.  swindle on|off  This command  gives  you  control  over
+"swindle  mode."   When  on, and playing a game, Crafty will
+try to win drawn endings (according to the tablebases) if it
+has winning chances (like KR vs KB, for example).  This will
+put up very stiff "resistance" to accepting the draw,  while
+
+
+
+
+
+
+
+
+
+
+
+
+
+with  this  mode off, it may be very easy to draw a position
+once the tablebases say "drawn."  This mode is automatically
+turned  "off" during analysis or when annotating a game, and
+is only used when actually playing a game against  an  oppo-
+nent.  If there are no tablebases then this has no effect on
+the game at all.
+
+56.  tags  This command will simply display the current  PGN
+tags (you can edit them with the various PGN commands).
+
+57.   test  <filename>  [n] This command will run a suite of
+positions (the file must be in "Crafty" format as  explained
+below)  and  produce  a  summary  of  how many it got right,
+wrong, etc.  It uses the time per  move  you  set  with  the
+(typically)  st  <n> command.  The optional parameter [n] is
+the "early exit" counter.  If Crafty finds,  and  holds  the
+solution  move  for  n  iterations,  it  will  terminate the
+search.  I use this to make a win at chess  run  take  <  15
+minutes,  even  though  the  time  per  position is set to 1
+minute, by setting n to 2.  After  two  correct  iterations,
+Crafty  goes on to the next problem.  For absolutely correct
+results, this is not advisable as it could obviously  change
+its  mind later on, but for performance analysis, this saves
+a lot of time.
+
+The test suite contains the following  lines:   (this  is  a
+sample from my test suite for Win At Chess.)
+
+title wac299
+setboard 1n2rr2/1pk3pp/pNn2p2/2N1p3/8/6P1/PP2PPKP/2RR4 w
+solution Nca4
+
+title wac300
+setboard b2b1r1k/3R1ppp/4qP2/4p1PQ/4P3/5B2/4N1K1/8 w
+solution g6
+
+end
+
+The  title  command  simply displays this message in the log
+file so you can look at the  output  and  figure  out  which
+position it goes with.  This is optional, but useful.
+
+The  setboard command sets the position as explained before.
+
+The solution command gives the set of solution moves (one or
+more  moves  that  are  separated by blanks) and/or a set of
+"anti-solution" moves (moves that  must  not  be  played  to
+count  the  position as correct.)  "anti-solution" moves are
+simply followed by a "?" character, for example:
+
+solution Bxa7?
+
+The solution command supplies a set of key moves,  and  then
+
+
+
+
+
+
+
+
+
+
+
+
+
+starts  the search.  If, after the search terminates, one of
+the key solution moves was chosen (or none of the anti-solu-
+tion  moves were chosen) the position is counted as correct.
+
+The final line should be "end" although end-of-file  or  EOF
+will also be detected in this case.
+
+57.    time   CPU|elapsed|<values>   This  command  controls
+whether the program uses CPU time  or  wall-clock  time  for
+timing.   for tournament play, it is safer to use wall-clock
+timing, for testing it may be more  consistent  to  use  CPU
+timing  if the machine is used for other things concurrently
+with the tests being run.
+
+time is also used to set the basic search  timing  controls.
+the general form of the command is as follows:
+
+      time nmoves/ntime/[nmoves/ntime]/[increment]
+
+nmoves/ntime  represents  a  traditional  first time control
+when nmoves is an integer representing the number  of  moves
+and  ntime  is  the total time allowed for these moves.  the
+[optional] nmoves/ntime is a traditional secondary time con-
+trol.   increment  is a feature related to ICS play and emu-
+lates the Fischer clock where <increment> is  added  to  the
+time left after each move is made.
+
+as  an  alternative,  nmoves  can be "sd" which represents a
+sudden death time control  of  the  remainder  of  the  game
+played in ntime.  the optional secondary time control can be
+a sudden-death time control, as in the following example:
+
+        time 60/30/sd/30
+
+this sets 60 moves in 30 minutes, then game in 30 additional
+minutes.  an increment can be added if desired.
+
+One final example is the following:
+
+        time sd/15
+
+which is a simple game/15 setting.  This command can also be
+used to perform the same function as  the  "level"  command.
+For  example, to set up a classic ICS 2 12 game, the follow-
+ing would would work:
+
+        time sd/2/12
+
+59.  trace <n>  This command is used to make crafty  display
+the  tree  as it searches a position.  Due to the incredible
+speed at which this program can  search,  however,  this  is
+less than useful since it can swamp any known display driver
+and make things scroll impossibly fast.
+
+
+
+
+
+
+
+
+
+
+
+
+
+Also note that this command  usually  is  disabled,  because
+Crafty  is  generally  compiled  with the -DFAST flag, which
+removes the trace output code from the search to make things
+slightly  faster.   You  will have to recompile, without the
+-DFAST, if you want to use this.  It's utility  is  limited,
+except for debugging, anyway.
+
+60.  usage <n> is simply a way to modify Crafty's time usage
+to fit your tastes.  You can "suggest" a time limit with any
+of the options discussed previously, but if you use anything
+other than the "st" command, Crafty will do its best to  use
+time  as  you  suggest, but it also anticipates that it will
+save some time by pondering, etc.,  and  will  therefore  be
+more aggressive at trying to use time.  if <n> is a positive
+integer, it is taken as a percentage and crafty will compute
+the  time  limit  it  thinks  is appropriate for the current
+clock settings, then increase this limit by this  percentage
+(50  would  make it take 1.5 times longer than normal.)  -50
+would make it take 1/2 the time it would normally take.
+
+Crafty adjusts the usage  internally  based  on  time  left,
+opponent's  time left, how quickly or slowly the opponent is
+moving, etc.  Further modifying things with this is  danger-
+ous, but possible.
+
+61.   whisper/kibitz <n>  These commands are used to control
+what Crafty will whisper or kibitz on a chess  server.   The
+options  are  (1)  only  whispers or kibitzes mate announce-
+ments; (2) adds time, score, depth to the  previous  option,
+but  no  PV  or moves.  (3) adds the PV.  (4) adds book move
+information to the output.  The remaining two options gener-
+ate  a  lot  of output and should be used with caution.  (5)
+displays the PV after each iteration completes.  I use  this
+when using my custom interface to let Crafty observe/comment
+on games in progress on ICC.  Noise can be used  to  prevent
+shallow  searches from generating output and keeping "noise"
+down on the games being watched.  (6) basically  will  whis-
+per/kibitz  nearly  everything you see on the console from a
+search, each PV when it changes, fail highs and  fail  lows,
+etc.   A  significant  amount of output that should be care-
+fully weighed before turning it "loose."
+
+62.  xboard  This command turns on Xboard/WinBoard  compati-
+bility mode, and makes Crafty behave somewhat like GnuChess.
+This is designed to be used *only* when Crafty is  interfac-
+ing  with  Xboard/WinBoard.  Crafty will not work with these
+two GUIs without this option, and  really  won't  work  very
+well with this option if it is not connected to one of them.
+
+63.  There are other commands that are not documented.  They
+are  part  of  the  xboard protocol and really should not be
+used by the normal user.  You can find all the  commands  in
+option.c should you be interested.
+
+
+
+
+
+
+
+
+
+
+
+
+
+                Opening Book Setup and Usage
+                ----------------------------
+
+Crafty   uses   two   pre-compiled   opening  books,  called
+"book.bin" and "books.bin".
+
+The file book.bin is usually build from a  large  text  file
+containing  PGN  games,  often  taken from collections of GM
+games.  Building book.bin is a simple exercise and  requires
+nothing  other than the raw input file you are going to use.
+Generally this will be either medium.zip or the set of  four
+files  large[1-4].zip,  all  of  which are stored on the ftp
+machine ftp.cis.uab.edu/pub/hyatt/.
+
+To create the file book.bin, you need a PGN game  collection
+that is a *real* PGN-compliant file.  Supposing this file is
+called "large.pgn" you would use the following command:
+
+book create large.pgn <m> [n] [wpct]
+
+The only thing you have to supply is <m>, a number  indicat-
+ing  how  many  moves from each game are to be stored in the
+book.bin database.  I typically use  60,  which  stores  the
+first  60  moves  from  each  game.   Increasing this number
+slightly increases the probability that Crafty will stay  in
+book  longer,  but it also increases the probability that it
+will follow a game too far, so that it begins to reach posi-
+tions  where  the move actually played might not be the best
+move, letting it fall into a bad hole.  Increasing this also
+increases the size of the database as well.
+
+You  can  decrease the size of the book, and also reduce the
+number of ugly moves by  specifying  <n>,  which  says  that
+unless  a  move  is  played in at least N games, the move is
+discarded.  This will substantially decrease the size of the
+book.bin  file,  and  also  eliminate single game moves that
+often have significant errors or blunders.
+
+You can increase the quality of  book  lines  by  specifying
+<wpct> which is the "winning percentage".  This is specified
+as a percentage of lost games, and is used to discard  moves
+that  led  to mostly losses.  A safe value is 50, which says
+that if a particular opening move didn't win at least 50% as
+many  games  as it lost, the move is culled.  A value of 100
+would mean that moves  are  culled  if  they  produced  more
+losses than wins, and is really a strict criterion.
+
+After creating book.bin, you need to create books.bin.  This
+is a small version of book.bin, which is  intended  to  give
+you  more  control over the moves/openings Crafty will play.
+This is usually built from the file  start.pgn  on  the  ftp
+machine,  but  you  can  modify this file to suit your taste
+easily.  To build books.bin, you use the following command:
+
+
+
+
+
+
+
+
+
+
+
+
+
+books create start.pgn 60
+
+Again, 60 is what I use, but none of my start.pgn  lines  go
+anywhere  near that many moves.  The main point here is that
+in start.pgn, you can append a "!" to any move you want, and
+when  it  is  Crafty's  turn to move for that color, it will
+play from the set of moves with "!" if there are any, ignor-
+ing the rest of the book moves.  If you only want it to play
+1. e4 as white, you would just enter the short game:
+
+[Crafty only plays 1. e4] 1. e4!
+
+and you are finished!.  You can enter as many as  you  want.
+If  on  the other hand there is a move you don't want Crafty
+to play, then follow that move with a "?" and it will  never
+play  it.  Moves in books.bin that are not flagged with ! or
+? don't have any influence on Crafty's choice at all.
+
+Here's how the files are used.  When searching  a  position,
+Crafty  first enumerates the set of moves it can find in the
+opening database.  It then does the same for  the  books.bin
+database,  and performs a "merge" operation to combine the ?
+and ! flags...  The purpose of the books.bin file is to give
+you  a  small  database that you can easily modify, rebuild,
+and repeat this process over and over.   Since  it  takes  a
+fraction  of a second to completely rebuild this file, it is
+very easy to modify this to control what Crafty  will  play,
+without having to rebuild the large database.
+
+One  important characteristic of the PGN input is the Result
+tag must be specified in most of the lines,  because  Crafty
+counts  wins,  losses  and draws for each book move and uses
+these counts with some of the book selection  options  given
+below.
+
+How the flags are used.
+
+The  ! and ? flags should only appear in the small books.bin
+file, although there is no reason why they can not appear in
+the  large  file  as  well.  For this discussion, it doesn't
+matter since Crafty takes the  moves  from  both  files  and
+"merges" the flags/etc into one entry for each move.
+
+Quite simply, if any book legal book move has a ! flag, then
+Crafty will only play moves from the set of moves which  all
+have  the ! flag.  If a move has a ? flag, then that move is
+immediately removed from the set of possible book moves.  If
+the only legal book move has a ? flag, it will not be played
+as a book move and Crafty will simply pretend that it  found
+no book moves and will execute a normal tree search.  Pretty
+simple.
+
+How to control the frequency of opening move selection.
+
+
+
+
+
+
+
+
+
+
+
+
+
+A new feature in version 15.15  and  beyond  allows  you  to
+append a PGN comment to any move in a text file used to cre-
+ate books.bin, of the form {play nn%}.  This will force  the
+move  it  follows  to be played that percentage of the time,
+regardless of the normal book-ordering values based on  fre-
+quency and so forth.
+
+Note  that  {play  0%}  will  not  prevent a move from being
+played at all, as this will look just like a  move  with  no
+percent specified.  To avoid playing a move, use the ? flag.
+
+How does Crafty choose book moves?
+
+Crafty's book  selection  algorithm  depends  on  two  user-
+defined values that can be set at any time during a game:
+
+book random <n>
+
+book width <w>
+
+The  selection  algorithm  first finds the set of legal book
+moves as above.  This set will either be  all  !  moves,  or
+will  have  no ! moves in it.  This set is then sorted based
+on the setting of book random.  Here's the options:
+
+book random 0.  This is a special case for  book  selection.
+Crafty simply takes the set of book moves, and searches only
+these moves using a normal alpha/beta  search,  but  with  a
+shorter  than usual time limit.  It then plays the move that
+produces the best search value.  This has one serious disad-
+vantage  in  that there is no randomness to this at all.  It
+will always play the same move in the same position,  unless
+the  evaluation is modified, or the time per move is differ-
+ent enough to let the search find a different move from  the
+book move set.
+
+book  random  1.   This  enables  a random form of book move
+selection, but you have a lot of control over how moves  are
+randomly  chosen.  The moves are ordered, based on 4 parame-
+ters:  frequency of play, win/lose ratio, static  evaluation
+and  learned  results.  Normally these are factored into the
+value used to sort the moves, based on default settings that
+you  can  modify  by  using  the  command  "bookw  option N"
+"option" should be "freq", "ratio", "eval" and  "learn".   N
+should be a number between 0 and 1.
+
+Crafty finds the min and max values for each of the 4 param-
+eters, and then maps this into the  range  0-1000  for  each
+parameter.   Each parameter is multiplied by the correspond-
+ing "weight" you have assigned, and this is used as a  value
+to  sort  the  moves  from low to high.  Note that the first
+sort value is always the "play percent" to move them to  the
+top  of  the  list.   For  moves  with  equal "play percent"
+
+
+
+
+
+
+
+
+
+
+
+
+
+values, the normal sort-value is used  as  the  second-level
+sort  variable  (if  no moves have a play-percent, then this
+second-level variable is the only one used, of course.)
+
+Once Crafty has sorted the moves as  given  above,  it  next
+excludes  any  book moves which have 0 wins.  This culls the
+odd lines where a player chose a bad line and lost  quickly.
+With  zero  wins,  it  will never be chosen, although Crafty
+will happily follow it from the other side.  :)  This is not
+anywhere  near  perfect,  however,  because an opening could
+have 1 win and 19 losses and that still would  stay  in  the
+list.
+
+If  a  move  has a learned value of > 100, this move is ele-
+vated in priority to that of a ! move, since it  appears  to
+win material instantly.  If a value is < -100, it is given a
+? since it appears to be a lemon.
+
+After this, the setting for "book width <w>" is used to keep
+the first <w> moves in the list, after the above culling has
+been completed.  The smaller you make <w> the  less  random-
+ness  you get, but the chance of Crafty popping out a really
+bizarre book move gets smaller as well.
+
+After sorting, the final step is to fold  in  any  mandatory
+"play percent" values.  What this step does is that it finds
+all the moves in the  "playable  move  set"  just  computed,
+which  have no percent-to-play value set.  It sums the sort-
+values for these moves, then adjusts the sort-values for the
+other moves so that their percentages will be honored.
+
+Once this has been done, crafty simply uses the "sort value"
+for each move to compute a total for  all  moves.   It  then
+generates  a  random  number  between  1 and this limit, and
+chooses the move that this probability distribution matches.
+This will certainly evolve over time as new ideas are devel-
+oped.
+
+For my play on ICC, I use book random 1, and  book  width  5
+normally,  although  for  titled  players this is reduced to
+book width 3.  For computers, I reduce this further to 2, to
+try  to  play  reasonable  openings and cull the gambits and
+things that don't work out.
+
+How does book learning work and  how  can  I  share  learned
+results?
+
+1.  *all* of crafty's "learned knowledge" is in the book.bin
+file.  It keeps the learned value and learned count right in
+the  book  file  for  speed.   You can't modify it, although
+"show book" will make crafty  display  all  the  book  stuff
+before it makes a move.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+2.   the  book.lrn file has two purposes:  (a) to serve as a
+log for your prying eyes, so you can see what it's  learned,
+against  whom, and what the score was that got its attention
+in the first place.  The values on  the  end  of  each  book
+line, inside the {} characters are as follows:
+    {value,  depth, rating_difference} value is the value of
+the "key" search that comes from the first 10 moves  out  of
+book.  it's in centipawns, and + is good - is bad.  depth is
+the depth the search reached at  this  "key"  position,  the
+deeper  the  search,  the more the value is "trusted."  rat-
+ing_difference is crafty's rating - opponent's rating a neg-
+ative  value means pay more attention to the score since the
+opponent is better than crafty, a positive  value  means  to
+take  the  score  with a grain of salt, because the opponent
+was weaker than Crafty.
+
+You can delete this file at any time, and it has  no  effect
+on  learning.   As  I mentioned, the learning takes place in
+book.bin... this is mainly for you to peek  at  if  you  are
+interested.   However,  this  is the "portable learning data
+file" also, and can be given to others to import into  their
+crafty,  where  it  will  affect  the opening book just like
+their crafty had  played  the  openings  and  got  the  same
+scores.  There are two ways to use such "lrn" files:
+
+1.   "import <filename>" will read <filename> and import the
+knowledge therein into your book.bin.  Since I use the  same
+learning  code  as is used when playing games, this informa-
+tion also gets appended to *your* book.lrn file as well,  so
+that your book.lrn always reflects *everything* your program
+has learned, so long as you don't ever remove this file.  It
+would  be a mistake to use this command on your own book.lrn
+file, because the things  would  get  counted  twice,  which
+might or might not be a good thing.
+
+2.   "import  <filename>  clear"  will  read  <filename) and
+import the  knowledge  as  above,  but  first  clears  *all*
+learned  results from book.bin.  you will want to do this if
+you import my book.lrn, *and*, you have  contributed  to  my
+book.lrn data by sending me yours.  I'll take care of elimi-
+nating duplicates if you screw up in what you send  me,  but
+once  you  send me something, you run the risk of getting it
+"back again" later.  This is going to  be  a  problem  until
+everyone  gets  used  to  sharing  something  that is rather
+"vapid" like this "learned info" is...
+
+Other than that, we are now "open for business"...  when the
+urge strikes you, email me your .lrn file, I'll keep a large
+master here and update it on occasion.   Probably  the  best
+thing  to  do  is  to  send  me  your  .lrn  and at the same
+*instant* delete yours.  This will capture anything  learned
+*after*  you  send  me the file, but you'll get it all right
+back with the next version of book.lrn  that  I  distribute.
+
+
+
+
+
+
+
+
+
+
+
+
+
+after getting this new book.lrn back, here's what you should
+do:
+
+1.  rename your old book.lrn to something else.   I'll  call
+it "book.lrn.old" here.
+
+2.   copy my blearn.dat to your machine, but *do not* put it
+in the directory  with  your  book.bin  and  books.bin  file
+because  it  will get confusing very quickly if you do.  put
+it somewhere else,  because  you  are  going  to  remove  it
+quickly anyway.  I'll call it new.lrn for this example.
+
+3.  import new.lrn clear
+    import book.lrn.old
+
+and you are ready to rumble again.  The first command clears
+the learned values, sucks in my new learn file  and  updates
+everything.   the second command re-learns everything you've
+learned since you sent me the  last  book.lrn  file.   After
+doing  this your book.lrn will have my .lrn stuff, plus your
+old.lrn stuff, just waiting to be sent to me again...
+
+If this is confusing, I can probably add an  automatic  com-
+mand to do all of this by renaming book.lrn, etc.  Hopefully
+this is not too error-prone for the time being anyway...
+
+What is this new Position Learning I've heard about?
+
+Crafty now has a "permanent" hash table that  is  kept  from
+game  to  game.   A position gets into this "hash file" when
+Crafty executes a search and the search  value  is  signifi-
+cantly lower than the last search value.
+
+When this happens, Crafty stores the current information for
+this position in the permanent hash file, which can hold  up
+to  65536  positions.   Once  it fills up, the positions are
+replaced on a FIFO basic always keeping the most recent  64K
+entries.
+
+Each  time crafty starts a search, the positions/scores from
+this file are stuffed into the normal  transposition  table,
+and  used during the search just like any other table entry.
+Here's how it helps:  In a game that was played, the follow-
+ing moves and scores were found by crafty (playing white):
+
+1.   Ng5  (+.277)   h6  2.  Nh7 (+.321)  Kg8 3.  Qh5 (+.133)
+Qg7 4.  Ng5 (-2.122) hxg5
+
+So, the knight got trapped at h7, and at move 4 crafty  dis-
+covered  that  this  is gross and "learns" this result/posi-
+tion.
+
+We play the exact same game again:  except that  two  things
+
+
+
+
+
+
+
+
+
+
+
+
+
+can  happen here.  It might be that Ng7 is the *only* square
+the knight can move to here, which means this whole thing is
+forced.  the first search would find:
+
+1.  Ng5 (-2.122) if the search can reach 8 plies deep, which
+happens even in 5 second games.  It's learned  that  Ng5  is
+bad.   It  stores *this* position in the permanent hash file
+also, and the next time you try this same trap, it will dis-
+cover  4-5 moves earlier that if the knight gets to g5 it is
+in trouble.  Each game will diverge from the first game  3-4
+moves earlier.  Simple and effective.
+
+2.   Ng5 might not be forced, and if not, it knows Ng5 loses
+a piece for a pawn, so it will promptly play something else,
+which is exactly what is desired.
+
+This  is  implemented  with two (count 'em, two) files.  One
+file "position.bin" is a binary file that contains the  hash
+table  entries, and it right at one megabyte in size, *max*.
+(16 bytes per hash entry X 65536 entries = exactly one  meg,
+but  I  have 8 extra bytes for the FIFO queue implementation
+and to see how many entries are currently in the file if  it
+is not full.
+
+The  second file is "position.lrn" and is, you guessed it, a
+file that can be shared with others, just like book.lrn.  It
+contains all information needed to reconstruct the position,
+the score, the depth, etc.  and also included the  pgn  tags
+for who was what color and when the game was played...
+
+This data can be imported with the new "import" command (the
+old book learn <filename> is no longer  around)  which  will
+import  either  book.lrn type data or position.lrn type data
+and can tell them apart without your having to do  anything.
+The  <clear>  option  is still there, should you want to use
+it, and simply removes  the  position.lrn  and  position.bin
+files before starting the import process for position learn-
+ing.
+
+This can be turned off, if you like,  by  checking  out  the
+"learn"  command,  which  gives  you the ability to turn off
+book learning (as it presently  works),  position  learning,
+and  the next book learning stage which will add to the book
+in addition to learning which book lines are good and bad.
+
+What is this new "result" learning?
+
+Result learning works just like normal book learning, except
+that  if  Crafty is checkmated or resigns, it will step back
+through the book line to find the last point  where  it  had
+more than one move to choose from.  It will flag the move it
+chose as "never play again".
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+This handles the case where the  first  ten  non-book  moves
+produce  reasonable  scores,  but  the  position is one that
+Crafty simply can't handle very well.  If it  loses  such  a
+game,  it  will  still  vary  the  next time this opening is
+played, as otherwise it would possibly repeat the same open-
+ing, and would certainly repeat the remainder of the game.
+
+All  three learning modes are turned on by default, although
+any of them can be disabled  with  the  appropriate  command
+option to "learn".
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+