White to play. Harvey–Roberson, Northumbria Masters 2021. Black’s last move, 37…Kf7-e7 looked plausible, but walked into a clever tactic. What was White’s next move? Answers should be emailed to chess@spectator.co.uk by Monday 13 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 b4+ Qxb4 2 Qa2+ Kb5 3 Qxb2 and the f6-pawn decides the game. Or if 1…Kxb4 2 Qe7! wins

Last week’s winner Mohammed Amin, Whalley Range, Manchester