[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "White to play and mate in 4"] [Black "?"] [Result "*"] [Annotator "peter"] [SetUp "1"] [FEN "3B4/3K4/2N1N3/3k4/3b4/1P1P1P2/3q4/8 w - - 0 1"] [PlyCount "7"] [SourceVersionDate "2023.03.04"] {[#]} 1. Be7 {threatening Nc7 mate} (1. Bc7 {does not mate in 4 because of the extra file available to the queen on the kingside} Bc5 2. Bb8 Qh2 {prevents mate in 4 but the mirror would be off the board in the 1.Be7 line}) 1... Be5 ( 1... Bb6 2. Bf6 {Threatening Ne7 mate} Bd8 3. Bd4 {Zugswang! Mate will follow wih Nc7, Ne7, Nb4 orf Nf4 depending on what Black plays}) (1... Qh2 2. f4 { now Black cannot stop both Nc7 mate and Mb4 mate}) 2. Bf8 {Threatening Ne7 mate } Bb8 {or any other square on this diagonal apart from d6} (2... Bd6 3. Bxd6 { with Nc7 or Ne7 to follow}) (2... Qg5 3. Nb4#) 3. Ne7+ Ke5 4. Bg7# *