The following is a list of free computer programs for playing Go. Some are also free software.
*19x19 **[http://www32.ocn.ne.jp/~yss/ Aya] Freeware program estimated at 7 kyu strength by the author. **GNU Go Being part of the GNU project, its full source code is available under the GNU General Public License. Tends to be considered the stronger of the programs listed here, ranking between 8k-9k. ** An open source go playing program written in . Full source code is available under the GNU General Public License. Supports board sizes up to the GTP limit (1x1-25x25) ** A new open source Go playing program written in Java, and released under the Apache Software License version 2.0. The program is currently very weak, and development appears to have stalled. ** A binary (executable) trial version is provided free of charge. Source code seems not to be publicly available. ** Full 19x19 board with AI opponent. Free to download. Source not available. ** Different board sizes. Free download. No source available. ** Easy to install. Strong play. Board can be 9x9, 13x13, or 19x19. Strength of computer opponent is customizable. Handicaps and komi are selectable.
*13x13 ** A binary (executable) is provided free of charge.
*9x9 ** from the Nihon Ki-in. ** Freeware version of The Many Faces of Go. **, winner of the 11th Computer Olympiad
*5x5 through 21x21 ** front end for GNU Go specialized on ease of use and realistic 3D visualization.
*Free ** , freeware to explore Go on 3D board with many different topology (cube, sphere, cylinder, torus, Möbius strip, ecc.).
Mac OS X
*GNU Go See description above. * See description above. * See description above. * Free graphical user interface that can be used to play against GNU Go or other human players across the internet or a local network. *, a free software derivative with less functionality (only allows playing against GNU Go) is distributed under the GNU General Public License. *, freeware to explore Go on 3D board with many different topology (cube, sphere, cylinder, torus, Möbius strip, ecc.).
*GNU Go See description above. * See description above. *Uligo * See description above. * Multi-function GUI for several board games, including Go. When playing Go, it relies on GNU Go or other [http://www.lysator.liu.se/~gunnar/gtp/ GTP] capable engines.
* Has AI opponent, but only plays in 9x9 or 13x13 *[http://www.lirmm.fr/~kiss/Go/ Go for PalmOS] Can play in 19x19. Requires Os 3.5 or Higher * Requires color display
* Free 9x9 version. Commercial version can do 9x9, 13x13, and 19x19. * DOS predecessor to Igowin. 9x9 only. * Cut-down version of Bruce Wilcox's EGO. You can choose between 19x19 or 9x9 boards. * Full 19x19 board with AI opponent. Free to download. Source not available. German language version only.
MIDlet * Free open source (GPL) software for playing 2-player Go. * Free open source (GPL) MIDlet for playing 2-player Go, viewing games and solving problems. * Free open source SGF editor. * A lot of features, including Joseki and IGS client. * Free. 2-player. Problems. * Free. Plays some weak moves.
* Playable from any java-enabled browser. According to the author, Ruhai Zhou, it is currently not strong. *JagoClient.