Last week’s puzzle was taken from the new book The Secret Ingredient to Winning at Chess by Jan Markos and David Navara, which I’ll be reviewing for British Chess News within the next week or two.

Black could have won had he found the amazing sequence 29… Ba3+! 30. Kxb3 a1N+!! 31. Rxa1 Qxb6+!! 32. Bxb6 Nd4+! 33. Kc3 (or 33. Bxd4 Rcb8+ 34. Kc3 Bb4+ 35. Kb2 Bd2+) 33… Rxc4+! 34. Kxc4 (34. Kd2 Nxf3+) 34… Rc8+ 35. Bc7 Rxc7# (A problemist would be horrified that c5 was controlled by two black units, though!)

David Navara writes about this: Black is objectively winning, yet I believe that in 90 per cent of practical games White players would win. If, on the other hand, you presented the position to grandmasters or international masters with a hint “Black to move wins”, the situation would be quite different. I would estimate that half of the players, or perhaps even more, would discover the correct continuation.

Did you discover it, I wonder?