Reversi is a computerised version of the board game Othello, in which two players take turns to place coloured counters on a chequerboard. The aim is to bracket the other player's counters with your own, isolating a line of captured counters which change colour and join your side. The winner has the most counters of his or her colour when the board becomes full.

Simple though the idea is, Reversi is an addictive strategy game and a popular subject for computerisation. This excellent program offers four levels of play against a human opponent, giving a range of response times between one second and 10 minutes. At the third level the Memotech plays a good game, responding in about 25 seconds. A bleep sounds when the computer has finished thinking. Invalid moves are not allowed.

Reversi uses a clear and attractive typeface. At any point in a game you may quit or call up detailed instructions, change the colour scheme, or use a "hint" facility which suggests your next move. Reversi is well-written, beautifully presented, but the price is perhaps a little excessive.

S.N.G.