Mate in 3

1.Bh5 threat 2.Qh1+ R×h1 3.Bf3; 1...Kc6 2.Qb5+ Kxb5 3.Be8; 1...Re3 2.Qb5+ Ke4 3.d5; 1...R×h5 2.Qb3+ Ke4 3.d5; 2...Kc6 3.Qc4; 1...e5 2.Bf7+ Kc6 3.Rc4. A flight-giving key sacrifices the bishop and there are two further sacrifices of the queen plus a switchback mate. The first four variations end in model mates.

Jacob Hoover: The key grants a flight and prepares a full-length threat. Taking the flight enables a different queen sacrifice and two other variations feature white battery plays.

Guy Meissonnier: Sacrifice of the Bishop with the threat 2.Qh1+, another sacrifice! 2.Qb5+ is a surprising move.