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CHESS(6)               BSD Reference Manual              CHESS(6)

       chess - GNU chess

       chess [ arg1 arg2 ]

       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  program,  type
       'gnuchess'  or type 'chesstool gnuchess' on a SUN worksta-
       tion where 'CHESSTOOL' is installed.  The 'gnuchess'  com-
       mand  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  argu-
       ment  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  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"  for  kingside  castling
       and "o-o-o" for queenside.

       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

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CHESS(6)               BSD Reference Manual              CHESS(6)

       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  com-
       mand  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 exam-
       ined to a depth of 4 ply (with extensions up to  11  addi-
       tional 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 varia-
       tion  and  the score during the search.  A score of 100 is

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CHESS(6)               BSD Reference Manual              CHESS(6)

       equivalent to a 1 pawn advantage for the computer.

       random -- causes the program to randomize its move  selec-
       tion slightly.

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

       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 equiv-
       alent  to  two  "undo's"  (e.g.  retract one move for each

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

       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.

GNU                     December 30, 1993                       3