gnugo - The GNU program to play the game of Go
gnugo [--boardsize <num>] [--color <color>] [--handicap <num>] [--komi
<num>] [--quiet] [-v, --version] [-h, --help] [--help debug]
[--copyright] [--mode <mode>] [--replay <color>] [-l, --infile
<filename>] [-L, --until <move>] [-o, --outfile <filename>] [--printsgf
<filename>] [-D, --depth <num>] [-B, --backfill_depth <num>] [--score
[estimate│finish│aftermath] ] [-a, --allpats] [-T, --printboard] [-d,
--debug <level>] [-w, --worms] [-m, --moyo <level>] [-b, --benchmark
num] [-t, --trace] [-r, --seed num]
GNU Go plays a game of Go against the user. It has many other features:
it can play against itself or another program, analyse and score a
recorded game. GNU Go is compliant with Go modem protocol, load and
save game in the Smart Game format.
GNU Go default is a simple alpha-numeric board display, but you can use
a client such as CGoban.
The game of Go
Go is a game of strategy between two players usually played on a 19x19
grid called goban. The two players put black and white stones on the
goban to enclose territory. Go was invented about 4000 years ago in
ancient China. Other names for this game are (Chinese) Wei Chi,
(Korean) Baduk and (Ing) Goe.
Playing a game in ASCII mode
To start a game with default options, just invoke "gnugo". The board
will be drawn at your terminal using ASCII letters. In this mode, you
can get help on available commands by the h key. To play as Black with
4 stones handicap, with a 0.5 komi, recording the game in the file
gnugo --color black --handicap 4 --komi 0.5 -o record.sgf
Playing a game with CGoban
CGoban is a general purpose client program by Bill Shubert for playing
Go. It runs under X Window System with a beautiful resizeable graphic
display. To use GNU Go under X Window System, obtain the most recent
version of CGoban from Bill Shubert’s web site
Start CGoban. When the CGoban Control panel comes up, select ‘Go
Modem.’ You will get the Go Modem Protocol Setup. Choose one (or both)
of the players to be ‘‘Program,’’ and fill out the box to the path to
gnugo. After clicking OK, you get the Game Setup window. Choose ‘‘Rules
Set’’ to be Japanese (otherwise handicaps won’t work). Set the board
size and handicap if you want. Click OK and you are ready to go.
In the Go Modem Protocol Setup window, when you specify the path to GNU
Go, you can give it command line options, such as --quiet to suppress
most messages. Since the Go Modem Protocol preempts standard I/O, other
messages are sent to stderr, even if they are not error messages. These
will appear in the terminal from which you started CGoban.
The game stops when both players pass. GNU Go will attempt to compute
and report the score to you. It may occasionally make mistakes due to
wrong evaluation of the status of a group. You can check the score as
follows. In ASCII mode, at the end of the game, stones believed dead
are marked in lower case letters, and you have the option of toggling
their status before counting. Using CGoban, you may use CGoban’s
counting facility to count the game using either Japanese or Chinese
Viewing a stored game
gnugo -l filename.sgf --mode ascii
loads filename.sgf and lets you navigate through the game by using the
commands forward, back, goto and last. It is not possible to navigate
through variations in ascii mode. You may also use CGoban to view
stored games. CGoban can navigate variations.
The files in the doc directory contain detailed documentation about
debugging options and internal program structure. Other documentation
may be found in comments throughout the source code.
Go Modem Protocol
The Go Modem Protocol is a standard interface between Go programs and
The Go Modem Protocol was developed by Bruce Wilcox with input from
David Fotland, Anders Kierulf and others. Any Go program *should* use
this protocol since it is standard. Since CGoban supports this
protocol, the user interface for any Go program can be done entirely
through CGoban. Using the Go Modem Protocol, you can play with another
computer running a different program (even on a different operating
system) using a modem, a serial cable or over the internet if the other
program also supports the protocol. You can also communicate with the
Go servers using CGoban.
Smart Game Format
Games (with comments, variations and other features) can be stored in
the Smart Game Format (SGF). This format originated in Anders Kierulf’s
program Smart Go. Martin Muller and Arno Hollosi developed the current
standard, which may be found at
GNU Go supports the Smart Game Format.
force the playing mode (ascii, gtp or gmp). Default is ASCII. If no
terminal is detected GMP (Go Modem Protocol) will be assumed.
replay the game generating moves for color, where color is white,
black, or both. (requires -l)
Don’t print copyright and other informational messages.
-l, --infile file
Load the SGF file (to score or analyze a recorded game).
-L, --until move
Stop loading just before move is played (e.g. 154 or L10).
-o, --outfile file
Save the played game to file in SGF format.
Set the board size to use (1-19). Default is 19, other common formats
are 13 and 9.
Choose your color (black or white). Black plays first, White gets the
Set the number of handicap stones.
Set the komi (points given to white player to compensate advantage of
the first move, usually 5.5 or 0.5). Default is 5.5.
Display the version of GNU Go.
Display help message.
Display help about debugging options.
Display copyright notice.
Debugging and advanced options:
Show board each move.
Level of play. (default 10; smaller=faster, weaker).
-b, --benchmark num
Benchmarking mode - can be used with -l.
Verbose tracing (use twice or more to trace reading).
-r, --seed num
Set random number seed.
Count or estimate territory of the input file. Usage:
gnugo --score estimate -l filename
Loads the SGF file and estimates the score by measuring the influence.
Use with -L if you want the estimate somewhere else than at the end of
gnugo --score finish -l filename
Loads the SGF file and gnugo continues to play by itself up to the very
end. Then the winner is determined by counting the territory.
gnugo --score aftermath -l filename
Similar to --score finish except that a more accurate but slower
algorithm is used to determine the final status of the groups.
If the option -o outputfilename is provided, the results will also be
written as comment at the end of the output file.
Load SGF file, output final position (requires -l).
If you find a bug, please send the SGF output file to firstname.lastname@example.org
together with a description of the bug.