Fairy-Stockfish is published under the GPLv3 license. Its code can be changed and shared using the same license.
Open source
Free and accessible for everyone
Fairy-Stockfish is published under the GPLv3 license. Its code can be changed and shared using the same license.
Customizable
Support for user-defined variants
Fairy-Stockfish supports playing custom variants by defining game rules via a configuration file.
Trainable
Support for NNUE
Efficiently updatable neural networks (NNUE) can significantly enhance playing strength.
Fairy-Stockfish is a chess variant engine derived from Stockfish designed for the support of fairy chess variants and easy extensibility with more games.
It can play various regional, historical, and modern chess variants such as
Despite Fairy-Stockfish’s generality the playing strength is on a very high level in almost all supported variants, especially when using NNUE. To only name a few it is the world’s strongest engine in Janggi, Crazyhouse, S-Chess, etc.
For compatibility with graphical user interfaces Fairy-Stockfish supports the UCI, UCCI, USI, UCI-cyclone, and CECP/XBoard protocols.
Latest Posts
This website just came to life today. It is still under construction, but hopefully will be a useful addition to existing documentation. If you find a mistake, have a suggestion for improvement, or are just curious about how this website is built, you can have a look at its code repository.
A new version of Fairy-Stockfish is available, see the release notes.
A new version of Fairy-Stockfish is available, see the release notes.