Knight Endings

The Knight ending is, in many respects, very close in nature to a pawn ending. There are two main similarities:

1. The role of the King is crucial (an active King is always a plus).
2. Calculation is very important, since in many cases a single tempo can easily decide the outcome.

Also, in case Knights are exchanged, a pawn ending occurs, making knowledge of pawn endings even more important.

Boleslavsky-Keres, Leningrad 1941

BLACK TO MOVE

The following ending shows how important calculation is. Black missed a win a few times and ended up losing the game. Basically, in the beginning position Black is obviously better, since he has an extra pawn. Another factor is the weak h3-pawn, which can be easily attacked. White's only chance in this game is to win either the g5- or d6-pawn.

1...Nd4?!

This move misses a relatively easy win. Black is ahead in material, but his g-pawn may be vulnerable to his opponent's Knight. Perhaps Keres miscalculated, since 1...Ng1 is fairly obvious here. What could he have possibly been afraid of?

In case of 1...Ng1, White can play 2.Nxe5! and now it looks like 2...dxe5 meets 3.d6 and the d-pawn appears unstoppable. Maybe Keres also saw that after 3...f3 4.Ke3, White stops the f-pawn, while the d-pawn seems to remains out of reach. However, it is not so! After 4...f2! 5.Kxf2 Nxh3+ 6.Ke3 Nf4 7.d7 Ne6, Black catches the pawn and wins the game, as was pointed out by IM Shereshevsky.

2.Nf6

Now White can attack both the g- and d-pawns.

2...Nb3 3.Ke2

The only move, since moving the Knight either to h7 or e8 would run into 3...Nc5+ winning the e4-pawn.

3...Nc5 4.Kf3 Nb3 5.Ke2 Nc5 6.Kf3

White is behind a pawn and obviously does not mind a draw, but Keres finds a winning idea.

6...Kc3!

The King enters the battle. Now e4 is in real danger, but it also appears that Black has abandoned his g5-pawn.

7.Ne8!

The only move. As pointed out by Shereshevsky, in case of 7.Nh7 Kd2 8.Nxg5 Kd3! is very strong, winning the e4-pawn due to zugzwang. Instead, White attacks d6, since his d-pawn is advanced fairly far.

7...Kd2! 8.Nxd6 Ke1!

Looks like the march of a madman at first, but Black actually threatens to checkmate his opponent!

9.Nc4

The only move once again. If 9.Nf7, then 9...Kf1! 10.Nxe5 (10.Nxg5 Nd3-+) 10...Nb3 leads to inevitable checkmate!

9...Kf1 10.Nd2+ Kg1 11.Nc4

11...Nd7?

Instead, 11...Nb3! threatening checkmate, would still win for Black. After 12.Ke2 Nd4+ 13.Kd3 f3 14.d6 f2 15.Ne3 (15.Nd2 Nb3, -+) 15...Ne6! 16.Kc4 Nf4 17.d7 Ng2, Black should win.

12.Nd6 Kh2?

Finally, Black makes a losing move. After 12...Nc5 Black would still be able to draw the game.

13.Nf7! Kxh3 14.Nxg5+ Kh2 15.d6 h3

It looks like Black has successfully stopped his opponent's pawn, while he is advancing his own. If White moves his Knight to e6 or f7, then Black moves his King to g1, winning. However, things are not always what they seem.

16.Nxh3!

Perhaps Keres missed this move.

16...Kxh3 17.g5

Suddenly Black is lost! Now his Knight can't stop both pawns.

17...Nc5 18.g6 Ne6 19.d7 Ng5+ 20.Ke2 Kg3 21.d8=Q, Black resigned.