Orca is a UCI-compliant chess engine written in Go that analyzes chess positions and computes the optimal moves.

Several installation methods are available:

• find the most recent stable release.
• using the go toolchain:

go install github.com/leonhfr/orca@latest

• compile from source (requires [email protected] and make):

git clone [email protected]:leonhfr/orca.git
cd orca
make build

Orca is not a complete chess software and requires a UCI-compatible graphical user interface (GUI) to be used comfortably. GUI options include SCID, CuteChess, Arena and Shredder.

In the future, Orca will be available as a Lichess bot.

option name Hash type spin default 64 min 1 max 16384
option name OwnBook type check default false

Available options are:

• Hash: size in MB used for the transposition table
• OwnBook: allow the engine to use its own opening book
• UCI_Chess960: sets the engine to Chess960 mode.