Can You Find The Winning Idea

There is a fundamental ending at the core of this problem that allows for a solution. Can you find it?

7R/5P2/1b5P/4K1k1/8/1p6/P7/5r2 w - - 0 1

Comments
No. 1-3
Alena
Alena

1.f8=Q Rxf8
2.Rxf8 bxa2
3.Ra8 Kxh6
4.Kf5 Kg7
5.Rxa2 Kf7
The black king is not in the corner. It's impossible to win for white here.

Yancey_Ward
Yancey_Ward

Editor

And why does 1.f8(Q) fail to win in this case- it also reduces to a R vs B ending.

Alena
Alena

V-1

1.h7 Kg6
2.f8=Q Rxf8
3.Rxf8 bxa2
4.h8=N+ Kg7
5.Ra8 a1=Q+
6.Rxa1 Kxh8
7.Ra6 Bc5
8.Rg6 Bf2
9.Kf6 Kh7
10.Kf7 Ba7
11.Ra6 Bb8
12.Ra8 Bc7
13.Rc8 Bf4
14.Rc4 Bg3
15.Rc3 Bh4
16.Rh3 Kh6
17.Rxh4+
It's a winning position for white.

V-2

1.h7 bxa2
2.Rg8+ Kh6
3.h8=Q#

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