Correct answer: Kb51...f5 2.N:e5# 1...e4 2.Nf4# 1.Nb2+?? 1...Kc3 2.Q:c4# but 1...K:e3! 1.Qb5?? zz 1...e4 2.Nf4# 1...f5 2.N:e5# but 1...a6! 1.e4?? zz
