No. 718

White to play and win. Composed by Alexey Troitsky, Novoye Vremya, 1895. Trapping Black’s queen looks unimaginable on such an open board, but it can be done. What is White’s first move? Answers should be emailed to chess@spectator.co.uk by Monday 5 September. There is a prize of £20 for the first correct answer out of a hat. Please include a postal address.

Last week’s solution 1 Qg6! threatens Qxg7 mate.

Last week’s winner Joe McKenzie, Bedford