Daily Chess Improvement: Endgame Calculation!

Endgame Improvement: Giri v Ding

Black to move. Win or draw?

Comments
No. 1-3
Alena
Alena

There are two equal winning lines. They are a6 and Ka3. I spent 40 minutes to work out the solution. I stumbled over the twelfth move. I had to repeat moves. The end of my solution is very beautiful. The white is in zugzwang and the black wins because of it.

1...a6
2.f5 Ka3
3.Kd3 Bb4
4.Kc4 Be7
5.b4 Bxb4
6.f6 Bf8
7.Kd5 Kb4
8.Ke6 a5
9.Kf7 Bc5
10.Ke6 Ka3
11.Kd5 Bf8
12.Kc4 Ka4
13.Kc3 Ka3
14.Kc4 Ka4
15.Kc3 Kb5
16.Kb3 a4+
17.Kb2 Kb4
18.Kc2 Bd6
19.f7 Bf8
20.Kb2 Bg7+
21.Kc2 Ka3
22.Kb1 Bf8
23.Ka1 Bh6
24.Kb1 Bg7
25.f8=Q Bxf8
26.Ka1 Bh6
27.Kb1 Bg7
It's a winning position for black.

Yancey_Ward
Yancey_Ward

Editor

I think 1.....Ka3 wins. It is possible that black can transpose with 1......a6, too, but I am not sure. The key, though, is a6- time is critical, and a6 does force the white king to go around through d5 if he wants to attack the a-pawn while drawing away the bishop with f8(Q). The line I gave above is the critical one, and it definitely wins- I verified in multiple lines after liquidating the white a-pawn. A very interesting ending!

Yancey_Ward
Yancey_Ward

Editor

Obviously, black cannot win with 1......Bxf4- while this exchanges down to a K vs K+P ending for black, as long as white makes black win the b-pawn up the board on b4 or b5, white's king can make it back to the corner. My first instinct was that this was drawn- it seemed to me on first glance that white would push the f-pawn through to f7 and then bring the king over to threaten the black a-pawn, but now I have some doubt. In some of the lines I am looking at, black might be able to work it that the pawn is on a6 rather than the more "obvious" a5, cutting off the b5 square to the white king while the bishop guards f8 and cuts off b4 and c5 thus costing white a tempo in getting to the a-pawn in time before black wins the queenside pawns and reconnects with his a-pawn. The line I am thinking of is 1.....Ka3 2.f5 a6! 3.Kd3 Bb4 4.Kc4 Be7. Needs more work, though- maybe white has a better defense than I see right now.

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