Correct answer: Nd31.Nf3?? zz 1...g4 2.Qh2#/Ng1#/Ng5# but 1...Kg4! 1.Nf7?? zz 1...g4 2.Ng5# but 1...Kg4! 1.Ng4?? (2.Qf3#) but 1...K:g4! 1.N