Chess

It was a blistery cold winter's morning as John Watson MD hurried up the steps of number 221b Baker Street. When he burst through the door he was startled to see the great detective sitting cross-legged on the floor, humming loudly. "Holmes, what's come over you?" he asked.

"Early mantra, my dear Watson. Make haste, we must get to the chess club. Mind the citrus limon on your way out."

Watson turned abruptly and almost collided with a large potted shrub he had not previously noticed.

"A lemon tree, my dear Watson, said the detective."

As they sped to the chess club, Holmes explained that there had been an incident at the club championships. He had been called in to unravel the mystery.

A tragic scene met them when they entered the rooms that housed the chess club. Two men lay dead at the board, with the pieces as indicated by the above diagram. White's hands were clasped around king and rook.

Watson thought he recognised the late player of the black pieces. "It's that Conservative MP in the divorce case," he said. "The one who had to pay his wife a mountainous settlement."

"Alimony Tory, my dear Watson," said the detective, "but I fancy our work will not take long." Glancing at the board, he said: "The game's a draw. Come doctor, we'll be home in time for lunch. Sole a la Monterey, my dear Watson, followed by a lamb entree, my dear Watson."

The doctor stood staring incredulously at the position. "Draw? What do you mean draw? Black's way ahead on material, it's his move, and he can take the rook on c8."

Holmes took a deep breath. "This may retard our lunch, Watson," he said in admonitory tones. "It's perfectly simple." He gestured towards the board. "Black has made three pawn captures, accounting for all the missing white pieces. White must have made one pawn capture, in order to promote his pawn to a white-squared bishop. The order in which things happened must have been thus: White's pawn advanced to g5, Black played hxg4, his rook emerged from h8, White played hxg8=B, the other bishop came to h7, Black played g6. On the Q-side, Black must have played axb6 and bxc5 to let the white rook in to a8 and c8, the black bishop in via a5, b6 and a7, and the white knight to a8. Only after all that can he have played b6 to let his other bishop emerge. But the captures on b6 and c5 demand the prior emergence of White's queen and bishop. Thus b3 must already have been played, and c4 also, to have let the rook emerge from a1. (Remember, White has just castled, so his king never previously left e1.) The position in which Black played b6, must therefore have been something like this." Holmes hastily rearranged the men on the board.

"You can seen now that Black's rook can only have reached a1 with the help of his king travelling to c1. Thus, after playing b6, his moves must have been Bb7, Be4, Qc8, Kd8, Qb7, Kc8, Qd5, Kb7 (which White meets by Ra7+!), Kc6, after which the moves Rb7, Ba7, Rb8 were played, then Bf5, waiting for White's Rf8 which permits Kb7, Ka6, Ka5, Kb4, Ka3, Kb2 and Kc1, after which the black rook goes to b2, b1 and a1. The bishop then follows it to b1, to permit the king to emerge, making the return trip to b7, when the sequence Rb8+, Kc6, Rb7, Bb8, Ra7, Qe4, Ra5, Kb7 permits the king to creep to g7 via c8, d8, e8 and f8. The the queen creeps in to b7 and c8 (met by Ra5) then f8 (met by Rb5 to let Black's rook in to a7, b8, c8, allowing Bb8, letting the white rook back to b7, b8 and c8. When you add it all up, it's 50 moves without a pawn move or capture. A draw, as I said some time ago.

"My stomach's rumbling," said the doctor.

"Alimentary, my dear Watson," said Holmes.