[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "White to play: Helpmate in 3."] [Black "?"] [Result "*"] [Annotator "peter"] [SetUp "1"] [FEN "B4K2/1b6/3rk3/8/5b2/8/6P1/8 w - - 0 1"] [PlyCount "7"] [EventDate "2010.04.18"] [SourceVersionDate "2020.04.01"] {[#]} {It is not hard to establish that moving the black king is not going to lead to the solution, therefore the black king must stay where it is. There are 4 dark squares around the black king to which it must be denied access. The white king covers one, the black rook and dark square bishop can occupy 2 more and the only piece that can cover the last dark square is the white pawn which must end up on g5. If the white pawn is covering f6 it cannot cover f5 so White's bishop must cover f5. That leaves e7 and d5 to control. The white bishop cannot deliver checkmate and cover d5 anf f5 at the same time, so must be covering f5 and e7 as it delivers mate, i.e. it must be on the h3-c8 diagonal. That leaves d5 to worry about and that must be occupied by Black's light squared bishop. So the final position is almost entirely resolved and it is just a question of finding the right moves to bring all the deductions together.} 1. g4 Bh1 2. Bg2 Be5 3. Bh3 Bd5 4. g5# *