Correct answer: Kd31...Ka5 2.b4# 1.b3?? zz 1...Ka5 2.b4# but 1...Ka3! 1.Kc1?? zz 1...Ka5 2.b4# but 1...Kb3! 1.Kd2?? zz 1...Ka5 2.b4# but 1...Kb3!