1 gnuchess(6) gnuchess(6)
9 gnuchess [ [[-|+]a] [-A aging-rate] [-b bookfile] [-B binbookfile] [-C
10 cache-table-size] [-c] [[-|+]D ] [[-|+]E ] [[-|+]e ] [[-|+]F ] [-H
11 hash-depth] [[-|+]h ] [-L language] [-l listfile] [[-|+]N] [[-|+]p ]
12 [-P plys] [-r length] [-s savefile] [-S binbooksize] [-t] [-c hashfile-
13 size] [-T transition-table-size] [[-|+]V] [-v] [-x] [-z search-fuzz]
17 Gnuchess plays a game of chess against the user or it plays against
20 Gnuchess is an updated version of the GNU chess playing program. It
21 has a simple alpha-numeric board display, an IBM PC compatible inter-
22 face, or it can be compiled for use with the chesstool program on a SUN
23 workstation or with the xboard program under X-windows. To invoke the
27 - simple curses based version
30 - fancy version using curses and inverse video on UNIX, or IBM
31 PC cursor controls and characters on MSDOS
37 - chesstool compatible version
40 - xboard compatible version
43 If one argument is given, it is the search time per move in [min-
44 utes:]seconds. So gnuchess 30 will generate one move every 30 seconds,
45 while gnuchess 5:00 will generate one move every 5 minutes.
47 If two or more arguments are given, they will be used to set tournament
48 time controls with the first argument of each pair being the number of
49 moves and the second being the total clock time in minutes[:seconds].
50 Thus, entering gnuchess 60 5 will set the clocks for 5 minutes (300
51 seconds) for the first 60 moves, and gnuchess 30 3:30 will allow 3 min-
52 utes and 30 seconds for 30 moves.
54 gnuchess 30 5 1 :30 will allow 5 minutes for the first 30 moves and 30
55 seconds for each move after that. Up to 4 pairs of controls may be
58 If no argument is given the program will prompt the user for level of
61 For use with chesstool or xboard, see the documentation on those pro-
65 At startup Gnuchess reads the binbook file if it is present. It then
66 looks for a book file. If it is present it adds its contents to the
67 binbook data. If the binbook file is writable a new combined binbook
70 The book gnuchess.book consists of a sequence of openings. An opening
71 begins with a line starting with a ! , the rest of the line is com-
72 ments. Following this is a series of moves in algebraic notation
73 alternating white and black separated by white space. A move may have a
74 ? after it indicating this move should never be made in this position.
75 Moves are stored as position:move so transpositions between openings
79 The hashfile if created should be on the order of 4 megabytes or
80 gnuchess -c 22. This file contains positions and moves learned from
81 previous games. If a hashfile is used the computer makes use of the
82 experience it gained in past games. Tests run so far show that it plays
83 no worse with the hashfile than without, but it is not clear yet
84 whether it provides a real advantage.
87 Note: Piece letters and legal castling notation is determined by the
88 language file. What is specified here is the default English.
90 Once gnuchess is invoked, the program will display the board and prompt
91 the user for a move. To enter a move, use the notation e2e4 where the
92 first letter-number pair indicates the origination square and the sec-
93 ond letter-number pair indicates the destination square. An alterna-
94 tive is to use the notation nf3 where the first letter indicates the
95 piece type (p,n,b,r,q,k). To castle, type the origin and destination
96 squares of the king just as you would do for a regular move, or type o-
97 o or 0-0 for kingside castling and o-o-o or 0-0-0 for queenside. To
98 promote a pawn append the type of the new piece to the move, as in
103 Use language lang from the file gnuchess.lang. If -L is not
104 specified it defaults to the language used in the first line in
105 the file. gnuchessr -L ger will use the german language.
108 Specify aging rate for hash table entries
110 [-]a Do [do not] search on opponents time.
113 Use bookfile for opening book.
116 Use binbookfile for binary opening book.
119 Specify evaluation cache table size (in entries).
121 -D Toggle DEEPNULL at runtime.
123 -E Toggle flag.threat.
125 -e Toggle flag.neweval to force evaluations instead of estimates
127 -F Toggle flag.noscore
130 pecify depth in plys for hashing.
133 Size of binbookfile for memory based and GDX books. For creating
137 Number of plys to include in the binbookfile. For generating a
143 Create a new HASHFILE. File size is 2^size entries of approxi-
146 [-]h Do [do not] use hashfile.
149 Pathname of the loadfile use with the get or xget.
152 Rehash length times in searching entries for position in trans-
156 Pathname of the save file to use with the save command.
158 -t Show statistics for HASHFILE
161 Set the transposition table size to size entries. (minimum is
164 -v Show version and patchlevel.
167 Use value as the evaluation window xwndw.
170 In addition to legal moves, the following commands are available as
171 responses. Note: command names are determined by the language file and
172 may vary with the implementation. This is default English.
174 alg -- allow algebraic input (not implemented)
176 Awindow -- change Alpha window (default score + 90)
178 Bwindow -- change Beta window (default score - 90)
180 beep -- causes the program to beep after each move.
182 bd -- updates the current board position on the display.
184 bk -- Print out all moves for this position from the book as: move
187 book -- turns off use of the opening library.
189 both -- causes the computer to play both sides of a chess game.
191 black -- causes the computer to take the black pieces. If the computer
192 is to move first the go command must be given.
194 eco -- Print out opening information for this game - lists ECO # and
197 coords -- show coordinates on the display (visual only)
199 contempt -- allows the value of contempt to be modified.
201 debug -- asks for a piece as color piece, as wb or bn, and shows its
202 calculated value on each square.
204 debuglevel -- sets level of debugging output if compiled with debug
207 depth -- allows the user to change the search depth of the program.
208 The maximum depth is 29 ply. Normally the depth is set to 29 and the
209 computer terminates its search based on elapsed time rather than depth.
210 If depth is set to (say) 4 ply, the program will search until all moves
211 have been examined to a depth of 4 ply (with extensions up to 11 addi-
212 tional ply for sequences of checks and captures). If you set a maximum
213 time per move and also use the depth command, the search will stop at
214 the specified time or the specified depth, whichever comes first.
216 easy -- toggles easy mode (thinking on opponents time) on and off. The
217 default is easy mode ON. If easy mode is disabled, the keyboard is
218 polled for input every so often and when input is seen the search is
219 terminated. It may also be terminated with a sigint.
221 edit -- allows the user to set up a board position.
223 # - command will clear the board.
225 c - toggle piece color.
227 . - command will exit setup mode.
229 pb3 - place a pawn on b3
231 Pieces are entered by typing a letter (p,n,b,r,q,k) for the piece fol-
232 lowed by the coordinate.
234 The usual warning about the language file applies.
236 exit -- exits gnuchess.
238 first -- tells the computer to move first. Computer begins searching
239 for a move. (same as "go").
241 force -- allows the user to enter moves for both sides. To get the pro-
242 gram to play after a sequence of moves has been entered use the 'white'
243 or 'black' command followed by 'go'.
245 gamein -- toggles game mode time control. Assumes the time specified
246 for time control is the time for a complete game. Input with the level
247 command should be the game time and the expected number of moves in a
250 get -- retrieves a game from disk. The program will prompt the user
253 go -- tells the computer to move first. Computer begins searching for a
254 move. (same as "first").
256 hash -- use/don't use hashfile.
258 hard -- think on opponents time
260 hashdepth -- allows the user to change the minimum depth for using the
261 hashfile and the number of moves from the begining of the game to use
264 help -- displays a short description of the commands and the current
267 hint -- causes the program to supply the user with its predicted move.
269 level -- allows the user to set time controls such as 60 moves in 5
270 minutes etc. In tournament mode, the program will vary the time it
271 takes for each move depending on the situation. If easy mode is dis-
272 abled (using the 'easy' command), the program will often respond with
273 its move immediately, saving time on its clock for use later on.
275 list -- writes the game moves and some statistics on search depth,
276 nodes, and time to the file 'chess.lst'.
278 material -- toggle material flag - draws on no pawns and both sides <
281 Mwpawn, Mbpawn, Mwknight, Mbknight, Mwbishop, Mbbishop -- print out
282 static position evaluation table
284 new -- starts a new game.
286 p -- evaluates the board and shows the point score for each piece. The
287 total score for a position is the sum of these individual piece scores.
289 post -- causes the program to display the principle variation and the
290 score during the search. A score of 100 is equivalent to a 1 pawn
291 advantage for the computer.
293 unpost -- turn off the post display.
295 quit -- exits the game.
297 random -- causes the program to randomize its move selection slightly.
299 rcptr -- set recapture mode.
301 remove -- backout the last level for both sides. Equal to 2 undo's.
303 reverse -- causes the board display to be reversed. That is, the white
304 pieces will now appear at the top of the board.
306 rv -- reverse board display.
308 setup -- Compatibility with Unix chess and the nchesstool. Set up a
309 board position. Eight lines of eight characters are used to setup the
310 board. a8-h8 is the first line. Black pieces are represented by
311 uppercase characters.
313 stars -- (gnuchessn only) add stars (*) to black pieces.
315 save -- saves a game to disk. The program will prompt the user for a
318 switch -- causes the program to switch places with the opponent and
321 test -- performs some speed tests for MoveList and CaptureList genera-
322 tion, and ScorePosition position scoring for the current board.
324 time otim -- time set computers time remaining, intended for synchro-
325 nizing clocks among multiple players. -- otim set opponents time
326 remaining, intended for synchronizing clocks among multiple players.
328 undo -- undoes the last move whether it was the computer's or the
329 human's. You may also type "remove". This is equivalent to two "undo's"
330 (e.g. retract one move for each side).
332 white -- causes the computer to take the white pieces. If the computer
333 is to move first the go command must be given.
335 xget -- read an xboard position file.
337 xwndw -- change X window. The window around alpha/beta used to deter-
338 mine whether the position should be scored or just estimated.