Correct answer: Nh1-f2 1.Nh1-f2 ! zugzwang. 1...Ng2-f4 2.Qh3-e3 # 1...Ng2-e1 2.Qh3-e3 # 1...Ng2-h4 2.Qh3-e3 # 1...Ng2-e3
