No. 313

White to play. This position is from Tal-Smyslov, Candidates Tournament 1959. White’s next move was a bombshell which led to a decimation of the black position and a quick victory. What was this key blow? Answers to me at The Spectator by Tuesday 13 May or via email to victoria@spectator.co.uk or by fax on 020 7681 3773. The winner will be the first correct answer out of a hat, and each week I am offering a prize of £20. Please include a postal address and allow six weeks for prize delivery.
 
Last week’s solution 1 Nc6
Last week’s winner Peter Skelly, Bedford