Black to play. Bertholdt-J. Penrose, Olympiad Final, Munich 1958. White has just played Bh3-c8, so that the Rc8 is imprisoned in case of the obvious capture on c3. Penrose found a much stronger response. What was it? Email answers to chess@spectator.co.uk by Monday 30 October. There is a prize of £20 for the first correct answer out of a hat.