While launching an attack in a game of chess it is most important to identify the defensive pieces which are guarding the King and then try to deflect them or exchange them. It is difficult for the attack to sustain if the defensive pieces continuously thwart all efforts.

In the game which follows, White is in an aggressive mode right from the word go. However what is noteworthy is that he has a certain plan in mind and at the right moment sacrifices an exchange for a crucial defensive piece — the light-squared bishop. This is a purely positional sacrifice based more on judgement of the position or intuition than calculation.

White: Utut Adianto Adianto (2605) – Black: Ruben Gunawan (2425)
Jakarta Gunadarma, 1996
King’s Indian defence
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7
The King’s Indian defence
4.e4 d6 5.f3
The Sammisch variation
5. ..0–0 6.Bg5 c5 7.d5 e6 8.Qd2 exd5 9.cxd5 a6
Sticking to opening theory
10.a4 Nbd7 11.Nh3
Aiming for the ideal f2 square
11. .. Re8 12.Be2
If 12.Nf2 Qa5 13.Be2 b5 14.0–0 bxa4 15.Rxa4 Qc7 16.Rfa1 Nb6 17.R4a2 Nfd7 18.Ng4 h5
12...Ne5
If 12...Qa5 13.0–0 h5 14.Nf2 Rb8 15.Kh1 Qc7 16.Be3 Nh7 17.Rfc1 Ne5 18.a5 Qe7 19.Na4 Nd7 20.Rab1 b5 21.axb6 Nxb6 22.Nxb6 Rxb6 23.b4 Qb7 24.Nd3 f5 25.Qc2 fxe4 26.fxe4 Qe7 27.Bf3 and White gained advantage in a previous game
13.Nf2 Qc7 14.0–0 Rb8 15.Bxf6
Interesting move where White gives up a strong bishop to gain initiative on the King side. If 15.Rfc1 Qa5 16.Ncd1
15...Bxf6 16.f4 Nd7 17.e5
A good advance
17. ..dxe5
If 17...Bg7 18.Nfe4 dxe5 19.d6 Qd8 20.f5
18.d6
White is trying to push his way through
18. ..Qd8 19.Nfe4
Still intent on posing threats rather than recover his pawn
19. ..Bg7
This is a very passive retreat by Black. He could have 19...exf4 20.Nxf6+ (20.Qxf4 Bd4+ 21.Kh1 f5 22.Bc4+ Kg7 23.Ng5 Be3 with advantage for Black) 20...Qxf6 21.Rxf4 Qg5 leading to an unclear position
20.f5
White is relentlessly pushing his pawns and is getting a strong bind on the King side
20. .. gxf5
If 20...Nf6 21.fxg6 hxg6 22.Nxf6+ Bxf6 23.Ne4 Bh4 24.Bc4 Be6 25.Bxe6 Rxe6 26.g3 Bf6 27.Qf2 Kg7 28.g4 Rxd6 29.g5 Bxg5 30.Qxf7+ Kh8 with White in a good position and if  20...Nf8 21.f6 Bh8 22.Nd5 also gives lot of scope for White
21.Rxf5 Nf8

Diagram 1
22.Raf1
White makes things more interesting with a positional exchange (rook for bishop) sacrifice. The sacrifice is prompted to give himself attacking chances as the white square bishop is crucial for defence and needs to be moved out.

22...Bxf5 23.Rxf5 Ne6
A mistake which gives White more initiative. Black could have tried 23...f6 24.Nd5 Nd7 25.Rh5 with the idea Bg4 followed by f5
24.Nd5
Both knights are strongly posted in the centre
24. ..Nd4
If 24...Rf8 25.Ndf6+ Bxf6 26.Nxf6+ Kg7 with an unclear position
25.Ndf6+ Kh8
If 25...Bxf6 26.Nxf6+ Kg7 27.Qg5+ Kh8 28.Qh6 and if 25...Kf8 26.Nxh7+ Kg8 27.Nef6+ Kh8 28.Rh5 Nxe2+ 29.Kh1 Nf4 30.Ng5+Nxh5 31.Nxf7 check-mate
26.Rh5 Nxe2+
He has nothing left to play now with the opponent’s pieces swarming around his King
27.Kf1 Bxf6
If 27...Qxf6+ 28.Nxf6 Bxf6 29.Qh6 Kg8 30.Qxh7+Kf8 31.Rg5
28.Qh6 and Black resigned as 28.Qh6 Kg8 29.Qxh7+ (29.Nxf6+ Qxf6+ 30.Qxf6 Nf4 31.Rf5 and white wins) 29...Kf8 30.Rg5 Qxd6 31.Nxd6 and it is all over.

Diagram 2
White to play and checkmate (There are interesting checkmating possibilities in this position)
1.Qh8 d4 2.Qh1 check-mate.
If 1. ..g3 2.Qh4 check-mate.
If 1. ..Kd4  2.Rf4 check-mate.
And if the rook moves anywhere then 2.Nc5 check-mate.