[White "   Dvoirys - Poliantsev, 1987.   "]   [Black "White to play and win"]   [Result "1-0"]   [FEN "2r1k2r/pp1n1ppp/2b1p3/q1b1P1B1/2B2Q2/2N5/PPP3PP/2KR3R w - - 0 1"]   {First of all, I have to apologize to everyone who tried to solve this puzzle. Because I haven't checked the solution with the engine prior to posting the puzzle and the official solution I blindly copied was flawed.   White has no way to win this.. but he can set Black some serious problems, starting with:}   1 Bxe6 fxe6 2 Rf1 Rf8   {Now White has a choice between two moves:}   3 Qc4 { the official solution and the better try}   (3 Qg4 { is met by}  3 ... Rf5  4 Rxf5 exf5 5 Qxf5  {and White doesn't have anything:}   {This is just scary looking for Black, but for instance}  5... Be7 6 Qe6 Qxe5  {is allright for him})   Bd5!  ({in the game,}  3...   Be7{  was played, when after}  4 Qe6  {White is indeed winning})  4 Nxd5 Rc6! { and now White has to find}  5 Qe4!?  {when Black can hold but has to be very accurate in defense:}