Chessmaster is a chess-playing computer game series which is now owned and developed by Ubisoft. It is the best-selling chess franchise in history, with more than five million units sold as of 2002. The Chessmaster series started with The Chessmaster 2000 by The Software Toolworks. It was published for Amiga, Apple II, Atari 8-bit, Atari ST, ZX Spectrum, Commodore 64, Amstrad CPC, MSX, Macintosh, and DOS. The game had a chess engine written by David Kittinger, and the manufacturer rated the game at 2000 Elo USCF; in reality, it plays at approximately 1550-1600 Elo (1750-1800 USCF).The Fidelity Chessmaster 2100 was published for the Apple IIGS.