Important to press home the advantage

It is easier to get a winning position but sometimes it can be difficult to convert it into victory. This, however, is not the case only with amateurs and beginners. It also can be seen at the higher levels of the game. Sometimes the most natural looking moves can be misleading and can immediately change the complexion of the game.

In the game which follows, the position is balanced but both players are error prone. White first gets into the driver’s seat and then fritters away the advantage with one wrong rook move. Black then with a neat combination settles the game in his favour.
White: Joel Lautier (2570) – Black: Alexei Shirov (2580)
Manila Interzonal, 1990

King’s Indian Defence

 1.d4 Nf6 2.Nf3 g6 3.g3 Bg7 4.Bg2 0–0 5.0–0 d6 6.c4 Nc6 7.Nc3 a6 8.h3 Bd7 9.Bg5 h6. The King’s Indian Defence is one of the sharp responses to the Queen’s Gambit and the players are following well known theoretical lines so far.
 10.Be3 Rb8 11.Nd5 b5. Black had played a novelty here. Previously played is 11...e6 12.Nxf6+ Qxf6 13.Qd2 Kh7 14.Rac1 Qe7 15.d5 Ne5 16.Nd4
 12.Nxf6+ exf6 13.cxb5
If 13.d5 Ne7 14.c5 Nf5
13...Rxb5. If 13...axb5 14.d5 Ne5 15.Nd4 Nc4 16.Bc1
14.Qd2. If 14.Qc1 g5 15.Nxg5 fxg5 16.Bxc6 Bxc6 17.Qxc6 Rxb2 18.Qxa6 Qa8
14...g5. If 14...Kh7 15.d5 Ne7 16.Nd4
15.d5 Ne7. If 15...Ne5 16.Nd4 (16.Rac1 Nxf3+ 17.exf3 f5) 16...Nc4 17.Qc3 Nxe3 18.fxe3 Rc5 19.Qd3 f5 20.Nxf5 and White is better
16.Nd4 Rxd5. If 16...Rb8 17.f4 with the intention of pushing f5
17.Bxd5 Nxd5. White has got a bishop and knight for his rook.
18.Nf5. If 18.Kh2 Qa8 Qc8 19.Nf5 (19.g4 h5) 19...Bxf5 20.Qxd5 Bxh3 21.Rfc1 Be6 22.Qc6 f5 23.Rc2 And if 18...Nxe3 19.fxe3
18...Bxf5. If 18...Nxe3 19.fxe3
19.Qxd5 Bxh3 20.Rfd1
Better appears 20.Rfc1
20...Re8. Black can also play 20. ..Qb8
21.Rac1. If 21.Rd2 f5 22.Bd4
21...f5 22.Rd2. If 22.Qc6 Rxe3 (22...Bxb2 23.Rc2 Be5 24.Qxc7 Qa8 25.Qc6) 23.fxe3 Qe7 24.Rd3 Bxb2 25.Rc2 Be5 26.Qxc7 Qf6
22...Rxe3. Black sacrifices the exchange. He could have maintained equality with 22. ..Qb8
23.fxe3 Qe7 24.Kf2
If 24.Qd3 Be5 25.Kh2 g4
24...Be5
Diagram 1
25.Rh1. A mistake! If 25.b4 h5 (25...Bxg3+ 26.Kxg3 Qxe3+ 27.Kh2 Qf2+ 28.Kh1) ]
25...Bxg3+. Black immediately strikes with a bishop sacrifice
26.Kxg3. If 26.Kf3 g4+ 27.Kxg3 Qxe3+ 28.Kh4 Qf2+ 29.Kh5 Qf4 30.Kh4 (30.Qa8+ Kg7 31.Qd8 g3) 30...Bg2 31.Qd4 (31.Qxg2 g3+ 32.Kh3 Qg4 checkmate) 31...Qg5+ 32.Kg3 Bxh1 and Black is better
26...Qxe3+ 27.Qf3. An invitation to exchange queens but the damage is already done. If 27.Kh2 Qf2+ 28.Kxh3 g4 checkmate
27...Qxd2. Black rightly grabs the rook
28.Qa8+ Kg7 29.Kxh3
If 29.Rxh3 g4 30.Rh1 (30.Rh4 Qe1+ And if 30.Rh2 Qe3+ 31.Kh4 Qe7+ 32.Kg3 Qe5+ 33.Kg2 Qxe2+ 34.Kg1 Qe1+ 35.Kg2 f4)
29...Qxe2. If 29...g4+ 30.Kh2
30.Qd5. If 30.Qg2 Qh5+ (30...g4+ 31.Kh2 Qe5+ 32.Kg1) 31.Kg3 Qg4+ 32.Kf2 Qd4+ 33.Ke1
30...Kg6. If 30...g4+ 31.Kg3 (31.Kh4 Qf2+ 32.Kh5 g3)  30...f4 31.Rg1 Qf2 32.Rxg5+ hxg5 33.Qxg5+
31.Qd4. Another mistake! White can try 31.Qg2 g4+ 32.Kh2 Qe5+ 33.Kg1 h5 34.Qh2 f4
31...f4 32.Rg1. If 32.Qd5 g4+ 33.Kh4 Qf2+ 34.Kxg4 Qg3 checkmate
32...f5 and White resigned for if 32...f5 33.Qxf4 Qh5+  0–1
Diagram 2
White to play and checkmate
1.Nc5+ Ke8  2.Rf8 checkmate.

Manisha Mohite