A famous chess grandmaster was found dead over his board, poisoned. His opponent claimed they were in the middle of an intense match. Detective Vance looked at the board: white's king was trapped in checkmate, yet white had three queens on the board while black had lost no pieces except pawns. Vance arrested the opponent for murder. Why?
Pawns can only promote to maximum one extra queen per pawn, so having three extra queens without capturing any black pieces is an illegal board state.
A player starts with one queen. To get extra queens, pawns must reach the opposite end and promote. Since black lost no pieces, white could not have captured anything to promote multiple pawns, proving the board was staged to look like a real game.
About this riddle
Detective riddles are tiny mysteries. Look for the detail in the story that does not fit; it is usually the clue that solves the case.
Difficulty: Hard. More like this: Detective riddles with answers or try Truth & Lie Island for a different kind of puzzle.
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