Alexander Alekhine v Juan Lacasa, simultaneous exhibition, Saragossa 1944. It was less than two years before Alekhine’s death, but the ageing alcoholic world champion still knew how to bamboozle his opponent in today's position even though he was playing around 20 other games at the same time. There is a well-known chess maxim that bishops of opposite colours — here White’s B operates on light squares, its counterpart on dark — increase the drawing chances in an endgame. So Senor Lacasa felt hopeful, since White (to play) has no entry routes for his rooks into the black position. Black’s plan is to do nothing for as along as it takes, for example by shuffling his rook between e7 and e6. What happened came as a shock. Alekhine whipped out his next turn, whizzed round the room to finish the remaining games, then collected his fee from the impressed organisers. What was White’s winning move?