Free chess software

chess-playing program for playing chess against the computer on a terminal or, more commonly, as a chess engine for graphical chess front-ends

XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.

PyChess is a free software chess client developed for GNU. It allows users to play offline or online via the Free Internet Chess Server (FICS). PyChess also incorporates a built-in chess engine, which in contrast to most other chess AIs is written in the Python language and focuses more on fun of play than raw strength. For more advanced users, PyChess allows for virtually any other external chess engine to be used with it.

database for chess on computer