This is the original chess program for the QL, written by Richard Lang and launched by Psion. It was originally published on the Sinclair Research Ltd label and later under Psion's own label. Psion Chess played a very strong game at the time and was famous for its 3D board display. A version of Psion Chess (running on a full 32-bit Sage computer) shared first place with three dedicated computer chess machines at the 4th World Micro Computer Chess Championships in 1984 - 1985. Interestingly, the September 1985 issue of QL User showed how the program could be defeated using the Queen's Gambit opening. The game was written entirely in 68000 machine code by Richard Lang, who had a lot of experience writing chess program for the Z80 and other systems. Psion chess for the Sinclair QL was, however, his first 68000 implementation. The 3D board and interface was written by Psion. A version was also available for DOS based systems, the Apple Mac and Atari computers. Also fun to know: the original price as at October 1984 was 19.95 Pounds Sterling. Gamewise, Psion Chess has both 2D and fixed-perspective 3D views of the board, visible both from the black and white sides, a full range of handicaps, move suggestions, solutions for mate problems up to 10 levels, remi offers and most other options a demanding chess player can ask for. A library of 50 master parties is also available for viewing. The Atari ST version has a ranking of 1960, whereas the Mac version has been rated at 1793 over 80 parties.