The Difference of One Tempo

Yesterday, I reached a clearly winning pawn ending and blew it. My opponent then returned the favor and gave me the victory. Our errors have some instructive value. There is a difference of one tempo between the position reached in the game and the position that it might have reached.

White to move

After 58...Kxh4

White is winning.

White to move

Possible position after 57...Kxh4

Black can hold the draw.

Let's examine the ending and the errors.

White to move

After 47...Ke6

48.Ke4??

Correct was 48.Kc4, when after 48...Kxf6 49.Kb5 Ke7 50.Kxa5 Kd7 51.Kb5 Kc7 52.Kc5 Kb7 53.Kd5 Kb6 54.Ke5 Ka5 55.Kf5 Kxa4

White to move

Analysis diagram

Black's king is too far from the h-file to prevent White's pawn from promoting. Had I played the correct 48.Kc4, this would have been the result. After my move, the game was equal until Black missed a critical move.

48...Kxf6 49.Kf4 Kg6 50.Ke5 Kg7 51.Kf5 Kh6 52.Kf6 Kh7 53.Kg5 Kg7 54.Kxh5

Black to move

It is clear that White will abandon the h-pawn and attempt to promote the a-pawn. What matters most is whether Black's king will be close enough to either trap White's king in front of its pawn or occupy a8.

54...Kh7??

54...Kf6 was the drawing move. After 55.Kg4 Kg6 56.Kf4 Kh5 57.Ke5 Kxh4, the second position at the top of the post is reached. Black's king will be able to occupy a8 or trap the White king on the a-file if it prevents this.

Instead, in the game continuation, White's king was one square further towards the queenside when Black played Kxh4. This square, a one tempo difference, was the difference in the game.

55.Kg5 Kg7 56.Kf5 Kh6 57.Ke5 Kh5 58.Kd5 Kxh4

We reach the position at the top of the post.

Black resigned after the subsequent moves: 59.Kc5 Kg5 60.Kb5 Kf5 61.Kxa5 Ke6 62.Kb6 Kd6 63.Kb7 Kc5 64.a5 Kb5 65.a6

White's king assures the pawn's safety.