For an opponent that is challenging, rather than unbeatable, one must usually set the computer to an “easy” level, or limit the number of moves the program looks ahead to one or two moves (“fixed depth 1” or “fixed depth 2” in computer chess argot). With the power of modern Macs, even Vanessa Chess is a much stronger player than most humans when set to full strength.
These days, chess strength should seldom be your primary decision factor in selecting a chess program. Sigma Chess beat all the others-their score against Sigma Chess was: Crafty 14.11B (47%), MacChess 4.0e (39%), Screamer 1.0 (25%), and Vanessa Chess 2.01 (10%). I’ve played 100-game matches between each of five programs using the excellent freeware chess umpire/database program, ExaChess Lite 2.1. Sigma Chess 5.12 is the strongest Macintosh freeware/shareware chess program reviewed in ATPM. Since Macintosh chess software is my hobby (I own dozens of Macintosh chess programs, and maintain the Macintosh Chess Software Index), I volunteered to write about them. Since that review, Sigma Chess was upgraded, and Vanessa Chess was released. ATPM reviewed five chess software programs in the September 1999 issue.
