Correct answer: Nf11...Kf3 2.O-O# 1.Rf1?? (2.Rf2#) but 1...K:h2! 1.N:h5?? zz 1...Kf3 2.Bd5# but 1...K:h1! 1.Ne2?? zz 1...Kf3 2.Bd5# but 1...