Master Chess, from Mikro-Gen, also provides a formidable game. It runs on a 48K Spectrum and has 10 levels of play which are numbered from zero to nine. If you do not know which move to make the computer will suggest one for you. The game also includes an analysis option which can be used to solve chess puzzles.
The Masterchess program is capable of all legal moves, including en passant and castling.