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Ending Challenge

White to move. Is this a win, loss, or draw for white. This requires considerable effort and deep calculation.

7k/1p4p1/3p4/3p3P/7P/2P2P2/8/6K1 w - - 0 1

I'm not sure that I made the best moves for black. I got a draw.

1.Kf2 d4
2.c4 Kh7
3.Kg3 Kh6
4.Kf4 Kxh5
5.Ke4 Kxh4
6.Kxd4 Kg3
7.Ke3 Kg2
8.f4 b6
9.Ke2 Kg3
10.Ke3 g6
11.Ke4 Kf2
12.Kd5 Kf3
13.Kxd6 Kxf4
14.Kc6 g5
15.Kxb6 g4
16.c5 g3
17.c6 g2
18.c7 g1=Q+
19.Kb7
It's a draw.

Without a deeper look at the entire line, Alena, I can't be sure it is actually drawn, but I stopped at move 7 in any case- black has a stronger immediate move at move 7 in reply to 7.Ke3. I am really only uncertain whether or not black can transpose to the same line after 7. ....Kg2?!

On further consideration, I do think 7. ....Kg2 is a flat out error. If you can work out black's win after 7. Ke3, you might be able to find white best play at move 1.

Thanks for your advice. I'll try to solve it tomorrow.It's time to sleep for me.

White needed a tempo to draw this game.

1.h6 gxh6
2.Kf2 Kg7
3.Ke3 Kg6
4.f4 Kf5
5.Kd4 Kxf4
6.Kxd5 Kg4
7.Kxd6 Kxh4
8.Kc7 Kg5
9.Kxb7 h5
10.c4 H4
11.c5 h3
12.c6 h2
13.c7 h1=Q+
14.Kb8
It's a draw.

So, where did the extra tempo come from? Black can, of course, just reply with 1. ...g6 rather than capture at h6 with the pawn, thus leaving the fundamental structure of the king side unchanged- the black king can still march and clean up the h-pawns, the g-pawn is still a g-pawn, the white f-pawn is still the same distance from the black king, and black can still play d4 in response to Kf2. Consider comparing the positions that arise in your first line and those that arise after 1.h6!! g6 2.Kf2 d4 etc.

V-2

1.h6 g6
2.Kf2 d4
3.c4 Kh7
4.Ke2 Kxh6
5.Kd3 Kh5
6.Kxd4 Kxh4
7.Kd5 g5
8.Kxd6 Kg3
9.Kc7 Kxf3
10.Kxb7 g4
11.c5 g3
12.c6 g2
13.c7 g1=Q
14.c8=Q
It's a draw.

V-3

1.h6 gxh6
2.Kf2 d4
3.c4 Kg7
4.f4 Kf6
5.Ke2 Kf5
6.Kd3 Kxf4
7.Kxd4 b6
8.Kd5 Ke3
9.Kxd6 Kd4
10.Kc6 Kxc4
11.Kxb6 Kd4
12.h5 Ke5
13.Kc5 Kf5
14.Kd5 Kg5
15.Ke5 Kxh5
16.Kf5
It's a draw.

Alena, consider the following, representative lines:

1.Kf2 d4
2.c4 Kh7
3.Ke2 Kh6
4.Kd3 Kh5
5.Kd4 Kh4
6.Kd5 Kg3
7.Kd6 Kf3
8.Kc7 Ke4
9.Kb7 Kd4 Position after 9 moves is 8/1K4p1/8/8/2Pk4/8/8/8 w - - 0 1

Versus:

1.h6 g6
2.Kf2 d4
3.c4 Kh7
4.Ke2 Kh6
5.Kd3 Kh5
6.Kd4 Kh4
7.Kd5 Kg3
8.Kd6 Kf3
9.Kc7 Ke4
10.Kb7 Kd4 Position after 10 moves: 8/1K6/6p1/8/2Pk4/8/8/8 w - - 0 1

Can you demonstrate and explain why these two final positions are different? These two positions in these lines represent the real principle underlying this beautiful Ryabinin study. Why does white lose the first one, but draw the second? At a glance, it appears to make no sense, right, but when you study them in detail, the reason becomes clear.

The two lines differ by the position of the pawn. It's very important because the pawn plays a key role.
In the first line the pawn guard f6 and the white king can't come near it and catch the pawn.
In the second line the pawn doesn't guard f6 and the white king come and grab the pawn.

V-1

10.Kc6 Kxc4
11.Kd6 Kd4
12.Ke6 Ke4
13.Kf7 g5
The position is lost for white.

V-2

11.Kc6 g5
12.Kd6 g4
13.c5 g3
14.c6 g2
15.c7 g1=Q
16.c8=Q
It's a draw

V-3

11.Kc6 Kxc4
12.Kd6 Kd4
13.Ke6 g5
14.Kf5 g4
15.Kxg4
It's a draw

V-4

11.Kc6 Kxc4
12.Kd6 Kd4
13.Ke6 Ke4
14.Kf6 g5
15.Kxg5
It's a draw.

I'm looking forward to your next puzzles.

Well done, Alena.

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