Usage

Online

Pychess

On Pychess you can play various chess variants against Fairy-Stockfish, e.g., Xiangqi, Shogi, Makruk, Janggi, and more.

FICS

To play bughouse against Fairy-Stockfish on FICS, you need to set up Fairy-Stockfish with XBoard/Winboard zippy mode.

GUIs

For offline usage of Fairy-Stockfish, download the latest release or compile it from source and use it together with one of the GUIs listed below or any other chess variant GUI that is compatible with the supported protocols. If you are unsure which version to download, use the most compatible versions for Windows or for Linux.

XBoard/WinBoard

Fairy-Stockfish also supports the CECP/XBoard protocol, so it can easily be used in XBoard/WinBoard. On Windows, it is recommended to use an up-to-date WinBoard version.

Setup steps on Windows

1. Download the Fairy-Stockfish executable from the latest release.
2. Download WinBoard and extract the zip archive.
3. Open the Winboard folder and double click the winboard.exe.
4. Click on Engines>Edit Engine List...
5. Add one line similar to "Fairy-SF" /variant=janggi -fcp "C:\fairy-stockfish.exe" (adjust the path to where you put the .exe in step 1, and replace janggi by the default variant of your choice). Click on commit changes and OK.
6. Click on Engines>Load New 1st Engine... and double click on Fairy-SF.
7. The default variant you entered in step 5 should now be loaded automatically.

Troubleshooting

• If an engine-defined variant uses special moves like, e.g., Janggi, Test Legality under Options>General... needs to be disabled or otherwise Winboard/XBoard might reject some engine moves.
• You can select other variants via File>New Variant..., or if the variant you are looking for is not in the list (as not all supported variants are displayed in the list) then you can enforce the variant by changing the default variant in the engine command from step 5 and redoing step 6. If you do this frequently, you can also copy&paste the entry in the variant list and create multiple entries for your favorite variants.

Setup steps on Linux

See this guide to compile XBoard on Linux. You can skip the --enable-zippy flag if you do not intend to use XBoard to run an engine on ICS/FICS.

Cutechess

Cutechess supports many of the built-in variants supported by Fairy-Stockfish. It is very well suited for playing games (engine/human), but analysis functionality is very limited.

Engines can be added via Tools>Settings. Select the Engines tab, click on + and select the engine executable via the Browse dialog.

PyChess

PyChess also supports some of the variants, including Crazyhouse, Losers, Giveaway, Three-check, King of the Hill, ASEAN, Makruk, and Sittuyin.

Shogi GUIs (USI-compatible)

Fairy-Stockfish can be used in gShogi and other USI compatible GUIs to play Shogi by adding it as a USI engine. In case of problems make sure in the engine configuration that the options Protocol and UCI_Variant are set to their defaults for the USI protocol, namely usi and shogi, respectively, and that you downloaded the large-board version (fairy-stockfish-largeboard...).

Fairy-Stockfish also has basic support for byoyomi time controls that are supported by some Shogi GUIs.

Xiangqi GUIs (UCCI-compatible)

Fairy-Stockfish can be used in Xiangqi GUIs by adding it as a UCCI engine. In case of problems make sure in the engine configuration that the options Protocol and UCI_Variant are set to their defaults for the UCCI protocol, namely ucci and xiangqi, respectively, and that you downloaded the large-board version (fairy-stockfish-largeboard...).

CLI & API

Command line

Fairy-Stockfish supports the UCI, UCCI, USI, and CECP/XBoard protocol. A variant can be selected via the UCI_Variant option in UCI/UCCI/USI or with the variant command in CECP. For variants that are not supported by any GUI, the CECP protocol is the least verbose for manual use via the command line.

E.g., to begin a game of Kyoto shogi after starting Fairy-Stockfish, enter:

1. xboard to set the protocol.
2. variant kyotoshogi to select the variant.
3. (Optional) d to print a board representation.
4. E.g., b1b2+ to make your first move.
5. go to ask the engine to play its first move.
6. Repeat steps 3.-4. in order to show the board and play moves. The engine will reply automatically to your moves once you sent one go command.

See https://www.gnu.org/software/xboard/engine-intf.html for more info on the CECP/XBoard protocol, e.g., on how to set the time control or the like.

Python binding

A python binding is also maintained in the repository and can be installed via the setup.py or as pyffish via pip. It can be used to query the engine for legal moves, FEN, etc. from python.