[Event "?"] [Site "?"] [Date "2020.07.19"] [Round "?"] [White "Mate in 2"] [Black "?"] [Result "*"] [Annotator "peter"] [SetUp "1"] [FEN "4R3/p2pKQ1r/r2p1Bpb/q2p2Pn/b3kp1N/pB2PN2/P1P5/1n2R3 w - - 0 1"] [PlyCount "3"] [SourceVersionDate "2020.04.01"] {This problem is based upon the idea of interference. White is nearly threatening mate in several different ways (e.g Kd8 or Qxg6) but black is defending against these mates. In the first 9 lines shown black blocks his own defences, so called interference.} 1. Bd4 {Setting up another potential mate, exf4, which currently does not work because of Qxe1.} Rb6 (1... Rc6 2. Kxd7#) (1... Bc6 2. Kxd6#) (1... Bb5 2. Bxd5#) (1... Rg7 2. Kf8#) (1... Bg7 2. Qxg6#) (1... Ng7 2. Qxf4#) (1... Nd2 2. exf4#) (1... Nc3 2. exf4+) (1... Rh8 { The first of the non-interference mates} 2. Qxg6#) (1... Rxf7+ 2. Kxf7#) (1... Bf8+ 2. Kxf8#) (1... Nf6 2. Kxf6#) (1... Ng3 2. Kf6#) (1... Bxb3 2. Kxd7#) ( 1... Qd8+ {other queen moves can be met by at least one of Kd8, Bxd5 and exf4} 2. Kxd8#) 2. Kd8# *