White to play. J. Polgar-Carlsen, Casual blitz game, Madrid 2022. Carlsen’s last move 15…Ra8-c8 was a losing blunder. How did Judit Polgar exploit it? Answers should be emailed to chess@spectator.co.ukby Monday 11 July. 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.