Knight moves have to be carefully executed to avert disaster

Chess Checks

However it is not easy to manoeuvre the knight as the whole calculation can go haywire with a wrong move.

In the game which follows, Black errs in manoeuvring his knight properly. First he retreats him back to the first rank and then starts the journey once again by landing on the wrong square. White then has no hesitation in wrapping up the game as this knight is then virtually pushed out of the game.

White: Heigi Gretarsson (2521) – Black: Heini Olsen (2292)
Gentofte, 1999; King’s Indian Defence
 1.c4 Nf6 2.Nc3 g6 3.d4 Bg7 4.e4 d6 5.f4

Aggressive continuation

 5. ..0–0 6.Nf3 c5 7.dxc5 Qa5 8.Bd3 Qxc5 9.Qe2 Bg4 10.Be3 Qa5 11.0–0
Castling to safety! The players are still following Opening book theory
 11. ..Nc6 12.Rac1 Nd7 13.Qf2 Bxf3
There was no retreat for the bishop so he might as well exchange it
 14.gxf3 Nc5 15.Bb1
Back to square one!
 15. ..Na4 16.Nxa4
He can also play 16.Nd1
16...Qxa4 17.Rfd1
If 17...Qa5 18.Rfd1 Rfd8 19.Kh1 Qc7 20.Rg1 e6 (20...e5) 21.f5 Qe7 22.Rcd1 Rd7 23.h4 (23.fxg6 fxg6 24.f4 Rf8) 23...Kh8 24.Bg5 Bf6 25.f4 Rg8 26.fxg6 fxg6 27.Rd3 Rdd8 28.Qh2 e5 leads to an unclear position
 17...Rfd8 18.Rd3
If 18.Kh1 e5 19.f5 Nd4 20.f4 Qc6 (20...Nc6 21.fxg6 hxg6 22.f5) 21.fxg6 fxg6 22.Qg2
18...Qa5 19.a3
If 19.Kh1 e5 20.Rd5 Qc7
19...Qc7
If 19...e5 20.fxe5 dxe5 21.b4 Qc7 22.Rd5 appears better for White
20.Kh1

Moving out from the Open file
20. ..b6
If 20...e5 21.fxe5 dxe5 22.Rd5 (22.c5 Rxd3 23.Bxd3 Nd4 24.Bc4 Kh8 25.b4 Rf8 with a slightly unclear position
21.b4 Rac8
If 21...e5 22.fxe5 dxe5 23.c5 Nd4 24.Ba2 and White is better
22.Ba2 Nb8?
It is difficult to understand this retreat as this just does not help Black’s cause. He could have tried to play actively with 22...e5 23.fxe5 dxe5 24.Rd5 Nd4 25.c5
23.Rcd1
Diagram 1
23. ..Nd7?
Once again not the right square for the knight. He was better on the square from where he had retreated, that is, on c6.
24.e5
Perhaps 24 Qd2 was worth a look!
24. ..Bf8
Another passive retreat! The better move would be 24...Nf8 25.Qd2 (25.exd6 Rxd6 26.c5 Rxd3 27.Rxd3 bxc5 28.bxc5 Nd7) 25...Ne6 26.c5 (26.exd6 Rxd6 27.Rxd6 exd6 28.f5 (28.Qxd6?? Rd8–+) 28...gxf5 29.Qd5 f4 30.Bg1 Be5) 26...bxc5 27.Bxe6 fxe6 28.bxc5 d5
25.Bb3 Nb8
Black is in a retreating mood and the last few moves just cannot be explained. If 25...dxe5 26.Qd2 also works better for White
26.e6
This pawn advance is the nail in the coffin
 26...Bg7
If 26...f5 27.c5 bxc5 28.bxc5 dxc5 29.Rd7  and if 26...fxe6 27.c5
27.exf7+
This pawn has marched all the way to the seventh rank and it proves crucial in the final analysis.
27...Kh8 28.c5
Opening up the position for his pieces to complete the mopping up operation
28...dxc5 29.Rxd8+ Rxd8 30.Rxd8+ Qxd8 31.bxc5 Nc6 32.cxb6 axb6 33.Qd2 Qxd2 34.Bxd2
The bishop battery will wrap up the game quickly now!
34. ..h6 35.Bc2 e5 36.Bxg6 Nd4 37.fxe5 Nxf3 38.e6 and Black resigned.
Diagram 2
White to play and win
1.Qxa6 bxa6 2.Rxb8+ Kxb8 3.Nc6+ Kc7 4.Nxe7 Bxe7 5.Bxh6 and White wins