1.Qd6 threatening Nb3# or Nc6# 1...b4 [1...Nc3 2.Nc6# (2.Nb3# ) ; 1...Nc1 This move defend on b3, but loosing control of c5, so.. 2.Qc5# ; 1...Nc5 2.Qxc5# ] 2.Nb3# [Bd5 is pinned and pawn has no more control of b4 2.Rc4# ] *