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

# Ending Challenge

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

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.

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.

Win for white.