Arasan is a chess program for Windows, Linux and Mac OS.
The latest version is Arasan 14.1, released in March 2012.
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 Shredder.
Arasan includes an opening "book" with over 200,000 moves.
Since version 14.0, the Arasan chess engine is licensed under the MIT License.