1.Nf4!
Bb8
2.Nxe6+
Ke8
3.Nc7+
Kd7
4.Kxa2
Kxd6
5.Na6!
[5.Nb5+?
Kc6!
6.Nc3
b5=
] 5...Ba7
switchback 6.b5!
Kd5
7.Ka3!
[Thematic try: 7.Kb3?
Kxd4!
8.Nb4
Bb8!
zz 9.Nc6+
Kc5
10.Nxb8
Kxb5=
] 7...Kxd4
8.Kb3!
zz 8...Kd5
[2nd main line: 8...Ke4
9.Kc4!
Ke5
10.Nb4
Bb8
11.Nc6++-
] 9.Nb4+
Kc5
10.Ka4!
Bb8
11.Na6+ .