Sherlock Holmes, playing White against Moriarty in the Reichenbach Falls championship final, was unperturbed. He calmly removed the black g-pawn, and moved his pawn from h5 to g6.
Moriarty shook his head in disapproval. "The en passant capture," he said, "is valid only if my last move was a pawn advance from g7 to g5. Can you prove it?"
"He's right, Holmes," Watson interrupted. "Without scoresheets, I fear the task is beyond you."
"I think not," said the great detective. "Examine the formation on the Q-side. Black's pawn captures account for every missing white man; the white pawn cannot have reached b4 until after a black pawn captured from b4 to a3, and the white Q-rook cannot have escaped until after b4 was played. The sequence of events must thus have been: b4xa3, b4, rook sidles in to a4 via a5, and finally Kb5-a5. And that final move must have been made in reply to d7xc6+, which in turn must have been played before bishop and rook emerged from c8 and a8. But both those pieces must have been taken by White's pawns on the K-side. There is only one way to retract the last few moves: Black has just played 1...g7-g5, preceded by White's g5xRh6, then Rd6-h6, g4-g5, Rd8-d6, f3xBg4, 0-0-0, f2-f3, Bc8-g4, Kb5- a5, dxc6+."
"Why cannot my last move have been g6-g5?" asked Moriarty.
"For then," explained Holmes, "we retract g6-g5, g5xRh6, g7-g6, g4-g5, Rd6-h6, f3xBg4, Rd8-d6, f2-f3, 0-0-0 and White is in retro-stalemate - he has no possible previous move." he looked up and saw Moriarty choking as he tried to eat the white g-pawn.
"My game, I think," Holmes said as Moriarty was carried off.Reuse content