GNU Chess is a free software chess engine and command-line interface chessboard. The goal of GNU Chess is to serve as a basis for research, and as such it has been used in numerous contexts.

GNU Chess

GNU Chess 6.0.0 running with the XBoard front end, v. 4.1.5.
Developer(s)	GNU Project
Initial release	1984; 38 years ago (1984)
Stable release	6.2.9[1]  / 13 July 2021
Repository	git.savannah.gnu.org/cgit/chess.git
Operating system	Linux, Unix, macOS, Windows
Type	Computer chess
License	2010[lower-alpha 1]: GPL-3.0-or-later 1992[lower-alpha 2]: GPL-2.0-or-later 1986: Chess-GPL[lower-alpha 3][2][3]
Website	www.gnu.org/software/chess/

This article is part of the series on
Chess programming
Board representations 0x88 Bitboards
Evaluation functions Deep neural networks Efficiently updatable neural networks Handcrafted evaluation functions Piece-square tables Reinforcement learning Stochastic gradient descent Supervised learning Texel tuning Unsupervised learning
Graph and tree search algorithms Minimax Alpha-beta pruning Principal variation search Quiescence search Monte Carlo tree search
Chess computers Belle ChessMachine ChipTest Cray Blitz Deep Blue Deep Thought HiTech Hydra Mephisto Saitek
Chess engines AlphaZero Chess Tiger Crafty CuckooChess Deep Fritz Dragon by Komodo Chess Fairy-Max Fritz Fruit GNU Chess HIARCS Houdini Ikarus Junior KnightCap Komodo Leela Chess Zero MChess Pro MuZero Naum Rybka Shredder Sjeng SmarThink Stockfish Turochamp Zappa
v t e

GNU Chess is free software, licensed under the terms of the GNU General Public License version 3 or any later version, and is maintained by collaborating developers. As one of the earliest computer chess programs with full source code available, it is one of the oldest for Unix-based systems and has since been ported to many other platforms.

Features

As of 2 September 2017 GNU Chess 5.60 is rated at 2813 Elo points (when using one CPU) on CCRL's 40-moves-in-40-minutes list. For comparison, the strongest chess engine in the list using one CPU, Strelka 5.5, has an Elo rating of 3108 (the 295 ELO point difference indicates that Strelka 5.5 would beat GNU Chess 5.60 in about 85% of games). On the same list, Fritz 8 is rated at only 2701, and that program in the 2004 Man vs Machine World Team Championship beat grandmasters Sergey Karjakin, Veselin Topalov and reached a draw with Ruslan Ponomariov. The IQ6 test suite (a collection of chess problems from Livshits's book Test Your Chess IQ) indicates that on a single core of an Intel Core 2 Duo CPU GNU Chess performs at the senior master/weak international master strength of 2500+ on the Elo rating system.^{[citation needed]}

It is often used in conjunction with a GUI program such as XBoard or GNOME Chess, where it is included as the default engine. Initial versions of XBoard's Chess Engine Communication Protocol were based on GNU Chess's command-line interface. Version 6 also supports the Universal Chess Interface (UCI). Since version 6.1 GNU chess supports a graphical mode for terminal emulators.

History

The first version of GNU Chess was written by Stuart Cracraft. Having started in 1984 in collaboration with Richard Stallman prior to his founding of the GNU Project, GNU Chess became one of the first parts of GNU.^{[citation needed]}

GNU Chess has been enhanced and expanded since. Versions from 2 to 4 were written by John Stanback. Version 5 of GNU Chess was based on the Cobalt chess engine written by Chua Kong-Sian.[4]

In 2011, GNU Chess transitioned to version 6, which is based on Fabien Letouzey's Fruit 2.1 chess engine. According to CEGT[5] version 5.60 of this code base is stronger than Fruit 2.3, the latest version of that chess engine.

See also

• List of open-source video games
• GNOME Chess
• GNU Go
• XBoard

Notes

References

External links

• Official website

На других языках

[de] GNU Chess

[ru] GNU Chess