Black to play. J. Polgar — Gaprindashvili, Novi Sad Olympiad 1990. Gaprindashvili’s next move prompted immediate resignation. What did she play? Email answers to chess@spectator.co.uk by 27 September. There is a prize of £20 for the first correct answer out of a hat. Please include a postal address and allow six weeks for prize delivery.

Last week’s solution 1 Qf6! blocks the f-pawn, so Bh6 and Qg7# is unstoppable. e.g. 1…Qxa2 2 Bh6 Qa5+ 3 Kd1 Qa4+ 4 Kc1 Qa1+ 5 Kc2 Qa4+ 6 Kb1 wins.

Last week’s winner Richard Craven, Bristol