[White "Daily tactics #12"]   [Black "Black to play and win"]   [Result "0-1"]   [FEN "2rr1bk1/1p3pp1/p6p/8/2n1PPP1/PnN4P/1PK3B1/1N2RR2 b - - 0 1"]   {In this position, a quiet move is required. Black would like to mate with knights on a1 and b3, Therefore}  1 ... Nca5!   {White has no defence to the threat of   2... Na1+  followed by  3... Nab3+ .  Virtually any move by White is followed by this sequence, which makes the king.   The hardest part of the puzzle is to spot the quiet move.}