"j2chess is a nice chess program that is written entirely in the Java programming language and consequently runs on any platform where a suitable Java Runtime Environment is available (version 1.4.2 or higher required)."
Note: The faster your processor, the better "thinking" you'll get with the program.
Also from the website:j2chess key features are:
- as long as you have java, j2chess is all-platform friendly :-)
- nice and easy to use
- strength and other various settings can be changed
- symmetric multiprocessing (SMP) support for maximum engine strength (= uses multi-cores/CPU system)
- casual, blitz and blitz Fischer style available for new games
- opening book with about 15,000 games
- export current game in Portable Game Notation (PGN)
- load games in Portable Game Notation (PGN)
- following languages are supported:
- english (default)
- português do Brasil
- and finally an impressive 2,224,527 nodes per second... If you have one of the new Apple MacPro Penryn 8 cores at 2.8 GHz! ;-)