1.g3+ Kh5

1...Kg5 2.f4+ Kh5 3.Nxf6++-

2.f4!

2.Nxf6+? Kg5 3.Nxg4 Rxg7 4.Nxh6 Kxh6=

2...Rxg7 3.Nxg7+ Kg6 4.Nf5 Rh5 5.Nc2!

Tries :

a) 5.Nd3? Rxf5 6.exf5+ Kxf5!= (6...Kh5? 7.Ne1+-)

b) 5.Ne7+? Kh6 6.Nf5+ Rxf5 7.exf5 Kh5=

5...Rxf5 6.exf5+ Kh5!

6...Kxf5 7.Ne3+ Ke4 8.Nxg4+-

7.Nd4! Zugzwang

7.Ne1 ? Kh6 8.Nd3 Kh5 9.Nc5 h6 10.Kh1 h2 11.Ne6 fxe6 12.fxe6 Kg6 13.f5+ Kg7=

7...Kh6

7...h6 8.Nf3+- similar a solution

8.Nb3!

8.Kg1? Kh5= 8.Ne2? Rh5 9.Ng1 Kh6 10.Kh1 Kh5=

8...Kh5 9.Nd2 h6

9...Kh6 10.Ne4 Kg7 11.Nf2 h5 12.Ne4 Kf8 13.Nxf6+-

10.Nf3 gxf3 11.Kxh3 f2 12.g4#