No. 666
White to play. Abdusattorov–Durarbayli, Sochi 2021. The endgame looks tricky, but White found a way to force a quick mate. What did he play? Email answers to chess@spectator.co.uk by Monday 16 August. 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.