GNU Go

The GNU Project's Go program, at its ASCII board.

▶ Play GNU Go free, in your browser, nothing to install

GNU Go is the GNU Project's program that plays Go, the board game of black and white stones on a grid of 19, 13 or 9 lines. It started in 1989 and was developed by many people until version 3.8 in 2009.

You play it as in a terminal: it draws the board in letters (X for Black, O for White, the last move in parentheses), and you type moves such as d4 or click a point. Commands set the board size, handicap and komi, take moves back, step through the game, save and load SGF files, and let two people play each other with force. After two passes it counts the game, and you can mark dead groups.

This is GNU Go 3.8's ASCII mode with its Monte Carlo player; its larger pattern and reading engine is not part of this port, so the computer plays more weakly than the original, especially on 19x19.

Screenshots

Counting at the end: dead stones in small letters

Controls

Keyboard	Type a move (d4, k10) or a command, and press Enter; several separated by ;
Mouse	Click a point of the board to type its coordinate
pass, undo, resign	Pass, take your last move back, give up
boardsize N, handicap N, komi K	Set up the game before the first move (also as options in the bar: --boardsize 13 --handicap 2)
level N	How strong the computer plays (default 10)
force MOVE, Two players	Two people at one keyboard: force plays a move for the side to move without the computer answering; the Two players box types force for you
save FILE, load FILE	Save the game as SGF in your account, load it again; Files lists them
back, forward, goto N	Step through the game tree
help	The list of commands
quit	Back to the game page

The original

GNU Go (1989) by Man Li, Wayne Iba, Daniel Bump, Gunnar Farnebäck, Arend Bayer and others (the GNU Project); C (command line). This port follows 3.8, the same rules, levels, graphics and sounds, running natively in the browser. License: GPL-3.0-or-later (Licenses & source). Players: 1 against the computer, or 2 at one keyboard.

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