Sigma GameWare

Sigma Chess is a freeware, master strength Macintosh chess program for Mac OS X. The feature set includes: Optional HIARCS engine, UCI Engine support, Databases, PGN/EPD, basic desktop publishing, endgame databases, novice levels, a true perspective 3D board, ExaChess compatibility and much more. Sigma also runs on Classic Mac OS, but this is no longer officially supported.