Correct answer: Rf5-b5 1.Rf5-b5 ! zugzwang. 1...Nd4-b3 2.Qd3*b3 # 1...Nd4-c2 2.Qd3-b3 # 1...Nd4-e2 2.Qd3-b3 # 1...Nd4-f3
