Correct answer: Rb51...Na4/Na6 2.Rd1# 1.Nb5?? (2.Nc3#/Nc7#) 1...e:f5 2.Nc7# 1...Na4 2.Nc7#/Rd1# 1...Na6 2.Rd1#/Nc3# but 1...N:b3!
