Grigory Levenfish (Black) Puzzle: Deflect — Mate in 3

Deflection is a tactical device that forces a defending piece away from a critical duty. In this position, Black exploits the exposed white king and the pressure along the first rank. A checking queen sacrifice-style idea drags the only suitable defender onto an unfavorable square, allowing the rook and queen to coordinate against the king. Although White has an advanced passed pawn, king safety is the urgent factor: a forced mating attack outweighs every material or promotion consideration.