gnuchess(6)gnuchess(6)NAMEgnuchess - Chess
SYNOPSISgnuchess [ [[-|+]a] [-A aging-rate] [-b bookfile] [-B bin-
bookfile] [-C cache-table-size] [-c] [[-|+]D ] [[-|+]E ]
[[-|+]e ] [[-|+]F ] [-H hash-depth] [[-|+]h ] [-L lan-
guage] [-l listfile] [[-|+]N] [[-|+]p ] [-P plys] [-r
length] [-s savefile] [-S binbooksize] [-t] [-c hashfile-
size] [-T transition-table-size] [[-|+]V] [-v] [-x] [-z
search-fuzz] arg1 arg2 ]
DESCRIPTION
Gnuchess plays a game of chess against the user or it
plays against itself.
Gnuchess is an updated version of the GNU chess playing
program. It has a simple alpha-numeric board display, an
IBM PC compatible interface, or it can be compiled for use
with the chesstool program on a SUN workstation or with
the xboard program under X-windows. To invoke the program
type:
gnuchess
- simple curses based version
gnuchessn
- fancy version using curses and inverse video on
UNIX, or IBM PC cursor controls and characters on
MSDOS
gnuchessr
- ASCII based version
gnuchessc
- chesstool compatible version
gnuchessx
- xboard compatible version
TIME CONTROLS
If one argument is given, it is the search time per move
in [minutes:]seconds. So gnuchess 30 will generate one
move every 30 seconds, while gnuchess 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
gnuchess 60 5 will set the clocks for 5 minutes (300 sec-
onds) for the first 60 moves, and gnuchess 30 3:30 will
allow 3 minutes and 30 seconds for 30 moves.
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gnuchess(6)gnuchess(6)gnuchess 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 chesstool or xboard, see the documentation on
those programs.
BOOK
At startup Gnuchess reads the binbook file if it is pre-
sent. 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.
The book gnuchess.book consists of a sequence of openings.
An opening begins with a line starting with a ! , the
rest of the line is comments. Following this is a series
of moves in algebraic notation alternating white and black
separated by white space. A move may have a ? after it
indicating this move should never be made in this posi-
tion. Moves are stored as position:move so transpositions
between openings can take place.
HASHFILE
The hashfile if created should be on the order of 4
megabytes or gnuchess-c 22. 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.
LEGAL MOVES
Note: Piece letters and legal castling notation is deter-
mined by the language file. What is specified here is the
default English.
Once gnuchess is invoked, the program will display the
board and prompt the user for a move. To enter a move, use
the notation e2e4 where the first letter-number pair indi-
cates the origination square and the second letter-number
pair indicates the destination square. An alternative is
to use the notation nf3 where the first letter indicates
the piece type (p,n,b,r,q,k). To castle, type the origin
and destination squares of the king just as you would do
for a regular move, or type o-o or 0-0 for kingside
castling and o-o-o or 0-0-0 for queenside. To promote a
pawn append the type of the new piece to the move, as in
e7e8q or c7c8r.
FUNCTION LETTERS
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gnuchess(6)gnuchess(6)-L lang
Use language lang from the file gnuchess.lang. If
-L is not specified it defaults to the language
used in the first line in the file. gnuchessr -L
ger will use the german language.
-A aging-rate
Specify aging rate for hash table entries
[-]a Do [do not] search on opponents time.
-b bookfile
Use bookfile for opening book.
-B binbookfile
Use binbookfile for binary opening book.
-C cache-size
Specify evaluation cache table size (in entries).
-D Toggle DEEPNULL at runtime.
-E Toggle flag.threat.
-e Toggle flag.neweval to force evaluations instead of
estimates
-F Toggle flag.noscore
-H hash-depth
pecify depth in plys for hashing.
-S size
Size of binbookfile for memory based and GDX books.
For creating a binbookfile.
-P plylevels
Number of plys to include in the binbookfile. For
generating a binbookfile.
-p Toggle flag.pvs
-c size
Create a new HASHFILE. File size is 2^size entries
of approximately 65 bytes.
[-]h Do [do not] use hashfile.
-l pathname
Pathname of the loadfile use with the get or xget.
-r length
Rehash length times in searching entries for posi-
tion in transposition table.
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gnuchess(6)gnuchess(6)-s pathname
Pathname of the save file to use with the save com-
mand.
-t Show statistics for HASHFILE
-T size
Set the transposition table size to size entries.
(minimum is MINTTABLE)
-v Show version and patchlevel.
-x value
Use value as the evaluation window xwndw.
COMMANDS
In addition to legal moves, the following commands are
available as responses. Note: command names are deter-
mined by the language file and may vary with the implemen-
tation. This is default English.
alg -- allow algebraic input (not implemented)
Awindow -- change Alpha window (default score + 90)
Bwindow -- change Beta window (default score - 90)
beep -- causes the program to beep after each move.
bd -- updates the current board position on the display.
bk -- Print out all moves for this position from the book
as: move response value
book -- turns off use of the opening library.
both -- causes the computer to play both sides of a chess
game.
black -- causes the computer to take the black pieces. If
the computer is to move first the go command must be
given.
eco -- Print out opening information for this game - lists
ECO # and variations
coords -- show coordinates on the display (visual only)
contempt -- allows the value of contempt to be modified.
debug -- asks for a piece as color piece, as wb or bn,
and shows its calculated value on each square.
debuglevel -- sets level of debugging output if compiled
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gnuchess(6)gnuchess(6)
with debug options.
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.
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.
edit -- allows the user to set up a board position.
# - command will clear the board.
c - toggle piece color.
. - command will exit setup mode.
pb3 - place a pawn on b3
Pieces are entered by typing a letter (p,n,b,r,q,k) for
the piece followed by the coordinate.
The usual warning about the language file applies.
exit -- exits gnuchess.
first -- tells the computer to move first. Computer begins
searching for a move. (same as "go").
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 'white' or 'black' command followed by
'go'.
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.
get -- retrieves a game from disk. The program will
prompt the user for a file name.
go -- tells the computer to move first. Computer begins
searching for a move. (same as "first").
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gnuchess(6)gnuchess(6)
hash -- use/don't use hashfile.
hard -- think on opponents time
hashdepth -- allows the user to change the minimum depth
for using the hashfile and the number of moves from the
begining of the game to use it.
help -- displays a short description of the commands and
the current status of options.
hint -- causes the program to supply the user with its
predicted move.
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.
list -- writes the game moves and some statistics on
search depth, nodes, and time to the file 'chess.lst'.
material -- toggle material flag - draws on no pawns and
both sides < rook
Mwpawn, Mbpawn, Mwknight, Mbknight, Mwbishop, Mbbishop --
print out static position evaluation table
new -- starts a new game.
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.
post -- causes the program to display the principle varia-
tion and the score during the search. A score of 100 is
equivalent to a 1 pawn advantage for the computer.
unpost -- turn off the post display.
quit -- exits the game.
random -- causes the program to randomize its move selec-
tion slightly.
rcptr -- set recapture mode.
remove -- backout the last level for both sides. Equal to
2 undo's.
reverse -- causes the board display to be reversed. That
is, the white pieces will now appear at the top of the
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gnuchess(6)gnuchess(6)
board.
rv -- reverse board display.
setup -- Compatibility with Unix chess and the nchesstool.
Set up a board position. Eight lines of eight characters
are used to setup the board. a8-h8 is the first line.
Black pieces are represented by uppercase characters.
stars -- (gnuchessn only) add stars (*) to black pieces.
save -- saves a game to disk. The program will prompt the
user for a file name.
switch -- causes the program to switch places with the
opponent and begin searching.
test -- performs some speed tests for MoveList and Cap-
tureList generation, and ScorePosition position scoring
for the current board.
time otim -- time set computers time remaining, intended
for synchronizing clocks among multiple players. -- otim
set opponents time remaining, intended for synchronizing
clocks among multiple players.
undo -- undoes the last move whether it was the computer's
or the human's. You may also type "remove". This is equiv-
alent to two "undo's" (e.g. retract one move for each
side).
white -- causes the computer to take the white pieces. If
the computer is to move first the go command must be
given.
xget -- read an xboard position file.
xwndw -- change X window. The window around alpha/beta
used to determine whether the position should be scored or
just estimated.
BUGSSEE ALSOchesstool(6)xboard(6)
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