Black to play. Adhiban-Warmerdam, Tata Steel Challengers, 2023. Adhiban’s last move, Nd4-e6, prepared a series of checks, starting with Nxg7+. Warmerdam’s response was a rude awakening. What did he play? Email answers to chess@spectator.co.uk by Monday 6 February. There is a prize of £20 for the first correct answer out of a hat.