Arasan is a chess program for Windows, Linux and Mac OS.
The latest version is Arasan 25.3, released in December, 2025.
Arasan has both a native user interface (for Windows only) and a console-based chess engine for use with Winboard or xboard. Arasan also works with Arena, another free chess interface, and with UCI-compatible programs like Fritz and Chessbase.
Arasan includes an opening "book" with over 900,000 moves.
Since version 14.0, the Arasan chess engine has been licensed under the MIT License.