b) 1.Bc8?
1.Ba6! Ka8 2.Nb2 Ba7 3.Nc4 Bb8 4.Nd2 Ba7 5.Nf3 Bb8 6.Nh4 Ba7 7.Nxg6 Bb8 8. Bb7+ Ka7 9.Ne7 g6 10.Nc8#
7... Kb8 8.Nf8 Ka8 9.Bb7+ Kb8 10.Nd7#
8... g6 9.Nd7+ Ka8 10.Bb7#
6... Ka7 7.Nxg6 ...
5... Kb8 6.Nh4 ...
4... Ka7 5.Nf3 ...
3... Kb8? 4.Ne5 dxe5 5.fxe5 Ka8 6.Bb7+ Kb8 7.e6 f4 8.e7 f3 9.e8=Q#
5... f4 6.e6 Ka8 7.Bb7+ ...
6... f3 7.e7 Ka8 8.Bb7+ ...
7... f2? 8.e8=Q#
4... Ka8? 5.Bb7+ Kb8 6.Nd7#
2... Ka7 3.Nc4 ...