Chess(GNU)

NAME
Chess - GNU Chess

SYNOPSIS
Chess [ arg1 arg2 ]

DESCRIPTION
Chess plays a game of chess against the user or it plays against itself.

Chess has a simple alpha-numeric board display or it can be compiled for use with the CHESSTOOL program on a SUN workstation. The program gets its opening moves from the file gnuchess.book which should be located in the same directory as gnuchess. To invoke the prgram, type 'gnuchess' or type 'chesstool gnuchess' on a SUN workstation where 'CHESSTOOL' is installed. The 'gnuchess' command can be followed by up to 2 command line arguments. If one argument is given it determines the programs search time in seconds. If two arguments are given, they will be used to set tournament time controls with the first argument being the number of moves and the second being the total clock time in minutes. Thus, entering 'chess 60 5' will set the clocks for 5 minutes (300 seconds) for the first 60 moves. If no argument is given the program will prompt the user for level of play. For use with CHESSTOOL, see the documentation on that program.

Once Chess 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 indicates 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" for kingside castling and "o-o-o" for queenside.

COMMANDS

In addition to legal moves, the following commands are available as responses.

beep -- causes the program to beep after each move.

bd -- updates the current board position on the display.

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 with the move and begin searching.

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.

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. Using the depth command allows setting depth to say 4 ply and setting response time to a large number such as 9999 seconds. The program will then 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).

easy -- toggles easy mode (thinking on opponents time) on and off. The default is easy mode ON. If easy mode is disabled, the user must enter a 'break' or '^C' to get the programs attention before entering each move.

edit -- allows the user to set up a board position. In this mode, the '#' command will clear the board, the 'c' command will toggle piece color, and the '.' command will exit setup mode. Pieces are entered by typing a letter (p,n,b,r,q,k) for the piece followed by the coordinate. For example "pb3" would place a pawn on square b3.

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' commands.

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

help -- displays a short description of the commands.

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

list -- writes the game moves and some statistics on search depth, nodes, and time to the file 'chess.lst'.

new -- starts a new game.

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

random -- causes the program to randomize its move selection slightly.

reverse -- causes the board display to be reversed. That is, the white pieces will now appear at the top of the board.

quit -- exits the game.

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.

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

white -- causes the computer to take the white pieces with the move and begin searching.

BUGS

Pawn promotion to pieces other than a queen is not allowed. En-Passant does not work properly with CHESSTOOOL. The transposition table may not work properly in some positions so the default is to turn this off.

SEE ALSO
chesstool(6)