1.h7!
[1.g7!?
Rb6+
2.Ka5
(2.Kxa7
Rg6
3.h7
Rxg7+-+
) 2...Bd6!
(2...Rg6?
3.h7
Rxg7
4.h8Q=
; 2...Bb4+?
3.Ka4=
) 3.Ka4
Rb4+
4.Ka5
Ka3
5.Ka6
Bb8
and Black wins: 6.g8Q
Rb6+
7.Ka5
Bd6
8.Qc4
(8.h7
Bb4#
) 8...Bb4+-+
] 1...Rb6+
2.Kxa7
Rxg6
3.h8Q
d3
4.Qc3!
[4.Qh2+?
Kb3
(4...Bb2?
5.Qf4=
; 4...Kb1
5.Qh1+
Kc2
6.Qa1
Bb2
7.Qa4+
Kb1
8.Qd1+=
) ] 4...Rd6
5.Ka8!!
zz [5.Qd2+?
Kb3
6.Qd1+
Kc4-+
; 5.Kb7?
d2
6.Qc2+
Ka1
7.Qc3+
Bb2-+
; 5.Kb8?
d2
6.Qc2+
Ka1
7.Qc3+
Bb2-+
] 5...d2
<main B> [5...Bb2
<main A> 6.Qa5+
Kb3
(6...Kb1
7.Qe1+
Ka2
etc) 7.Qb5+
Ka2
8.Qa5+
positional draw, or 8...Kb1
9.Qe1+
Kc2
10.Qf2+
Kb3
11.Qf7+=
] 6.Qc2+
Ka1
7.Qc3+
Kb1
8.Qb3+
Bb2
9.Qd1+
Ka2
10.Qa4+
Ba3
11.Qc2+
Ka1
12.Qc3+
Bb2
13.Qa5+
Kb1
14.Qf5+
Ka2
15.Qf7+
Ka1
16.Qa7+
Kb1
17.Qh7+
positional draw, or 17...Kc1
18.Qc7+=.