White to play. Carlsen–Vachier-Lagrave, Opera Euro Rapid 2020. Carlsen played 31 Bd4+ Rxd4 32 cxd4 Bxd4 which should be drawn, though he won in the end. Can you find the much s-tronger move which he missed? Answers to be emailed to chess@spectator.co.uk by Monday 22 February. 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 Qh1!, e.g. Ra6+ 2 Rxa6# Not 1 Qd4, 1 Qe5 or 1 Qe8 which allow 1…Ra6+
Last week’s winner Robert Overend, London W4