Correct answer: d4-d5 1.Ba1-c3 ? zugzwang. 1...Kc8-d8 2.Qc6-e6 zugzwang. 2...c7-c5 3.Bc3-a5 # but 1...Kc8-b8 ! 1.d4-d5 ! zugzwang. 1...K<