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Dark_Sage

jerry2468

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Fast_Thinker

Why would black promote to a bishop? A queen would be best.

Dark_Sage

If Black promoted to a queen on either b1 or c1, White can move its knight to d5 and then to c7# without worrying about Black attacking the c7 square. Black promoted to a bishop to trap his rook and hope for a stalemate. However, that does not work.