1.c7!
[1.bxa8Q+?
Kxa8
2.cxd7+
Ka7
3.d8Q
e1Q+
4.Kd7
Qb4
; 1.cxd7?
Bd6+
2.Kxd6
Rb8
; 1.Kxd7?
Bc7
2.Kxc7
(2.bxa8Q+
Kxa8
3.Kxc7
e1Q
) 2...Rb8
] 1...Nb6
[1...e1Q+
2.Kxd7
Ka6
3.bxa8Q+
Kb5
4.cxb8Q+
] 2.axb6+
[2.c8Q?
Bd6+!
(2...Nxc8+?
3.Kd7!
(3.bxc8Q
Bd6+
) ) ] 2...Kxb6
[2...Ka6
3.bxa8Q+
]
3.bxa8N+!
[3.bxa8Q?
e1Q+
4.Kd7
Bxc7
5.Qc6+
Ka5
6.Qxc7+
Kb4
; 3.c8N+?
Kc7
4.bxa8Q
e1Q+
5.Kf8
Kxc8
6.Qb7+
Kd8
7.Qxb8+
Kd7
] 3...Ka7
4.c8N+!
Ka6
5.Bc4+
Kb7
6.Bxe2
Kxa8
[6...Kxc8
main 7.Ba6#
; 6...Bd6+
7.Nxd6+
] 7.Bf3#