Chapter 47
Exploiting diagonals
Bishops are long-range pieces. A well-placed bishop, with other pieces on the board, is often no weaker than a rook. In this chapter, we will look at how to exploit bishops with 100% effectiveness – to do this, we usually need to open diagonals, not allowing the opponent to obstruct our bishop with pawns. If, on the other hand, the position is open, bishops feel at home. Bishops are especially effective when they work as a pair, on adjacent diagonals.
280 *
Alexei Shirov
2695
Lucas Brunner
2530
Biel 1995 (13)
The move …g7-g5 has seriously weakened the long diagonal, which White exploits with the aid of a small tactical operation:
32.♖xe5! ♗xe5 33.♕xe5 ♔h7 34.♗b2 ♖g8
When Black is forced to place a rook in such a position to avoid mate, the correctness of the sacrifice becomes obvious.
35.♗d4
Because there is no forced win, White simply strengthens the centralisation of his pieces, so as to be prepared to create threats on the kingside, and also support the advance of his passed pawns.
35…♗c2 36.♕d5 ♗a4 37.♘xf7 ♕c6 38.♘e5 ♕xd5 39.cxd5
With piece support, the passed pawns decide the game.
39…♔g7 40.c6 ♔f6 41.♘c4+ ♔e7 42.♗xa7 ♗b5 43.♗c5+ ♔f6 44.♘b6 ♔e5 45.c7
1-0
281 *
Kristian Trygstad
2308
Konstantin Sakaev
2607
Plovdiv tt 2010 (4)
The ♗f3 is the most important piece, and, given the weakening of the central light squares, is fully worth a rook.
12…dxe5!
Of course, Black could get excellent counterplay with 12…♗b7 or 12…♘c6, but the move played in the game is stronger.
13.♗xa8 ♘xa8 14.♕e2 ♗b7 15.♖f1 0-0 16.fxe5
White should not open lines, but, on the contrary, try to keep the game as closed as possible. Therefore, 16.f5 was essential, although Black’s initiative is very strong all the same.
16…♗xe5 17.♗e3 b4 18.♘a4 ♗c6 19.♘ac5 ♗b5 20.♘d3 ♗xb2
The white king has lost its only place of refuge, and now Black quietly brings up the rest of his pieces, to prepare the decisive blow.
21.♖d1 ♘c6 22.♗c1 ♗xc1 23.♖xc1 ♘b6 24.♘bc5 ♖d8 25.h4 ♖d5 26.♕f2 ♖f5 27.♕e3 ♘d5 28.♕h3 ♘f4 29.♕xf5 ♘xd3+ 30.♕xd3 ♗xd3 31.cxd3 ♕g3+ 32.♔d2 ♘e5
And Black won.
282 *
Leonid Stein
Tigran Petrosian
Moscow 1961
Usually in such structures, Black puts his bishop on a4, and if possible supports it by …b7-b5, cementing the queenside. This is exactly what Black would have done here if White had dawdled.
19.a4!
At the cost of a pawn, White activates his bishop, and it goes from being the most passive of his pieces to the most active.
19…♗xa4 20.♖a1 b5 21.♗a3 ♕d7 22.♖f2
White quietly increases the pressure, whilst Black cannot coordinate his pieces.
22…♖b7 23.♖af1 ♕d8 24.♕d1
There is now a threat of ♗g4-h3, followed by ♕d1-g4 and ♖f2xf7. He also threatens the immediate ♗g4xe6, and then ♕d1-g4.
24…♖h6 25.♗c1 ♖h7 26.♗xe6
Black resigned, since after 26…fxe6, there follows ♕d1-g4.
283 *
Vasily Smyslov
Petar Trifunovic
Zagreb 1955 (11)
White exploits the opportunity of weakening a group of squares in the enemy camp, at a minimal material cost:
24.♖xf6! gxf6 25.♗xf6
Now, the threat of the white queen appearing on h6 hangs over Black, as well as the possibility of a queen and bishop battery on the long diagonal.
25…♕h5 26.♕e3 h6
This attempt to ‘plug’ the holes fails, because the weaknesses are irreparable; he cannot even get his rooks onto open files.
27.h3
White could win by force with 27.♗b2 ♔h7 28.♕d4 ♖g8 29.♖e5 ♖ad8 (29…♗f5 30.♖xf5 ♕xf5 31.♗d3+–) 30.♗d5, but he did not want to risk miscalculating, and so makes luft just in case.
27…♕f5
On 27…♔h7, White wins by 28.g4 ♕a5 29.h4, with the threat of h4-h5.
28.♗c3 ♔h7
29.g4!
Black is so tied down that his queen and bishop lack even a single square each on the whole board.
29…♕g5
29…♕d7 30.♗d2!+–.
30.f4 ♕h4 31.♔g2
White is in no hurry. Another general strengthening move was 31.♕f3, with the deadly threat of f4-f5.
31…♖g8 32.♕e7
The simplest way to realise the advantage, but of course, White could also win the game with queens on, for example by 32.♕f3.
32…♕xe7 33.♖xe7 ♖ae8 34.♖xe8 ♖xe8 35.f5
When there is play on both flanks, two bishops usually cope easily with a rook. This case is no exception.
35…a6 36.♔f3 ♖c8 37.♗d4 b5 38.♗d3 ♖c1 39.fxg6+ fxg6 40.h4 ♖d1 41.♔e2 ♖h1 42.h5 ♖h2+ 43.♗f2 ♔g7 44.hxg6 h5 45.gxh5 ♖xh5 46.♗d4+ ♔g8 47.♗e4 a5 48.♔f3
Black resigned.
284 **
Gawain Jones
2648
Levan Pantsulaia
2595
Warsaw Ech tt 2013 (7)
The ♗g3 is the only piece defending the king. If it is lost, White risks being mated. This is what happens after…
55…♖e5!!
In the game, Black chose the waiting move 55…♔h8, and after 56.♘f6 ♕xe1 57.♗xe1, the position equalised out.
56.♗xe5 ♗xe5+
The bishops fire over the whole board, whilst the queen is ready to land a deadly blow from either side.
57.♘g3
57.♔g2 ♕g4+ 58.♘g3 ♗b7+–+.
57…♕a2+ 58.♔h3 ♗b7
He can only avoid mate on g2 with the help of the queen, but it is tied to the defence of the knight.
59.♕f1
59.♕e2 ♕e6+ 60.♔h2 ♗xg3+–+.
59…♕e6+ 60.♔h2 ♗xg3+ 61.♔xg3 ♕g4+ 62.♔f2 ♕f4+ 63.♔e2 ♗a6+
Winning.
285 **
Gudmundur Sigurjonsson
Leonid Stein
Reykjavik 1972
White has not yet completed his development, and in the absence of the light-squared bishop, his pawn structure looks rickety.
15…d5! 16.e5 d4!
This is the basis of Black’s whole idea. If he had to retreat the knight, White would entrench his knight on d4 and obtain the advantage, as the ♗b7 would be too bad.
17.♘xd4
White also has a lot of weaknesses after 17.♗xd4 ♗xf3 18.exf6 gxf6! 19.♗g1 ♗a8.
17…♘g4 18.♗g1
18…♘xh2! 19.♖fc1 ♘g4
White has a bad king, and his light squares are very weak – Black has a decisive advantage.
20.♘e4 ♗xb4! 21.♘g5 ♕d5
He would have won more quickly after 21…♖xc1 22.♖xc1 ♗d2.
22.♘e4 ♕xb3 23.♘xb3 ♗xe4 24.dxe4 b5 25.axb5 axb5 26.g3 h5 27.♔g2 ♗c3 28.♖ab1 ♖fd8 29.♖c2 ♖c4 30.♔f3 ♗xe5 31.♖xc4 bxc4 32.♘a5 ♖d3+ 33.♔g2 ♖d2+ 34.♔f3 ♗d4 35.♗xd4 ♖d3+ 36.♔g2 ♖xd4 37.e5 ♖d2+
0-1
286 **
Andrei Shchekachev
2565
Sergei Shipov
2620
St Petersburg ch-RUS 1998 (10)
It is clear that the white pieces are gathered dangerously around the black king. With his last move, Black advanced the pawn from h7 to h6, to avoid immediate mate.
19.♖e3
Building up the threats, although the same idea could have been pursued by the more precise 19.♖f3!?.
But 19.♘d5! wins practically at once, opening up both bishops and the a1-h8 and b1-h7 diagonals. 19…exd5 (White wins in interesting fashion after 19…♘e8 20.♖f3! exd5 21.exd5 ♗f6 22.dxc6 ♕xc6 23.♕f5 g6 24.♗xf6 d5
(24…♕xf3 25.gxf3 gxf5 26.♖g1+ ♔h7 27.♗xf5#)
analysis diagram
25.♖e6!! ♖d6 26.♖g3+–) 20.exd5 ♗xd5 (20…♘xd5 21.cxd5 ♗xd5 22.♕g4 f6 23.♕g6+–) 21.cxd5 ♖fe8 22.♗xf6 (a position with a large advantage results from 22.♖e3 ♕xd5 23.♖fe1 ♔f8 24.♗xa6) 22…♗xf6 23.♕f5 ♔f8 24.♕h7 ♖xe1 (24…g6 25.♖xe8+ ♖xe8 26.f5 g5 27.♕xh6+ ♗g7 28.♕xd6++–) 25.♖xe1 g6 26.f5! gxf5 (26…g5 27.♕xh6+ ♗g7 28.♕xg5+–) 27.♕xh6+ ♗g7 28.♕g5 ♕d7 29.♗xa6 (29.a4 ♖e8 30.♖f1 ♖e5 31.♗xf5 ♕e7 32.♕c1 ♖xd5 33.♕c8+ ♕e8 34.♕xa6
) 29…♖e8 30.♖xe8+ ♕xe8 31.♕xf5 ♕e1+ 32.♗f1 ♗e5 33.♕f3 – and with two extra pawns, White should win.
19…♔h8
Relatively best was 19…♕d7, but here too, after 20.♖g3 ♔h8 21.e5 dxe5 22.fxe5 ♘g8 23.♕g4 g6 24.♖h3, the black king is not to be envied.
20.♖g3?
And now, the line-opening sacrifice on d5 wins quite easily: 20.♘d5! exd5 (20…♘e8? 21.♕xh6++–) 21.exd5 ♗xd5 (21…♗e8 22.♗xf6 ♗xf6 23.♕f5+–) 22.cxd5 ♖de8 (22…♕d7 23.♗f5 ♕b7 24.♖fe1 ♖de8 25.♗xf6+–) 23.♗xf6 ♗xf6 24.♕f5+–.
20…♖g8 21.e5 ♘h7 22.♕h5?
The ♗b2 requires a new work location: after 22.♗c1 dxe5 23.fxe5 ♗f8 24.♗b1 ♕c7 25.♕h4 ♖d7 26.♗xh7 ♔xh7 27.♘e4 ♗xe4 28.♕xe4+ g6 29.♖d3
, White retains minimal pressure.
22…dxe5 23.♗xh7 ♔xh7 24.♕xf7 ♗f6
24…♗h4 25.♕g6+ ♔h8 26.♖g4 ♗f6 and Black is for choice.
25.♕g6+ ♔h8 26.♖h3 ♖gf8
27.fxe5?
Equality could be maintained with 27.♗a3! ♖d2 (27…♗e7 28.♖xh6+=) 28.♖xh6+ gxh6 29.♕xh6+ ♔g8 30.♕xf8+ ♔h7 31.♕xf6 ♖xg2 32.♘d5! ♖g6 (32…♗xd5? 33.cxd5 ♕xd5 34.♕xe5 ♕b7 35.♕h5+ ♔g7 36.♕f3+–) 33.♕h4+ ♖h6 34.♕e7+ ♕xe7 35.♗xe7 exd5 36.cxd5 ♗xd5+ 37.♔g1=.
27…♗g5! 28.♖g1 ♗xg2+
White resigned.
287 **
Gata Kamsky
2655
Garry Kasparov
2780
Manila ol 1992 (7)
Instead of White’s last move (11.g2-g4?), which only drives the black knight to an attacking position, he should have developed his kingside.
11…♘f4
Black is ready to give up a pawn, since if the sacrifice is accepted, the dark squares in White’s camp will be very weak.
12.♗c2 b5 13.♕f2
White tries to organise the exchange of the hated knight, whilst retaining his dark-squared bishop, but this loses precious time.
He could have tried to organise counterplay by creating pressure on the h-file, but after 13.h4 ♘d7 14.h5 ♘b6, Black still has the advantage.
13…♘d7 14.♘ge2 b4 15.♘a4
15…a5!
The most energetic, although he also gets a clear positional advantage after 15…♗h6 16.♘xf4 exf4 17.♗d4 ♗g7, ensuring the e5-square for the knight.
16.♘xf4 exf4 17.♗xf4 ♘e5
Because of the difference in strength between the pieces, Black has more than sufficient compensation for the pawn.
18.0-0-0
On 18.0-0, there follows 18…♗a6 19.♖fc1 ♕f6, forcing White to part with his dark-squared bishop.
18…♘c4 19.♗e3 ♘xe3 20.♕xe3 ♖b8
With this move, Black takes away the possibility of the white knight activating itself via b6.
21.♗b3 ♗d7 22.♔b1 ♕e8 23.♘b6 ♗b5 24.♖d2 a4
He could have won by force with 24…♕d8 25.♘a4 ♕d7 26.♘b6 ♕a7 27.♘c4 ♕a6! – the knight hangs, and …a5-a4 is threatened.
25.♗d1
On 25.♗c4, the strongest is 25…a3! 26.♖c2 axb2 – sooner or later, Black will carry out a winning attack on the queenside.
25…♖b7!
The white knight is in trouble, …b4-b3 is threatened, and after the exchange on this square, there is …♕e8-b8.
26.e5 b3!
Even stronger than the simple capture on e5.
27.axb3 axb3 28.♗xb3 ♕b8 29.♘c4 ♗xc4 30.♗xc4 ♗xe5 31.♕e2 ♕a7 32.♖c1 ♖a8 33.b3 ♗f4 34.♔c2 ♖e7 35.♕d3 ♕c5 36.♖b1 ♖e3 37.♕d4 ♖a2+ 38.♔d1 ♖xf3 39.♕xf4 ♖xf4 40.♖xa2 ♕g1+ 41.♔c2 ♕xh2+
White resigned.
288 **
Predrag Nikolic
2655
Evgeny Bareev
2675
Lyon tt 1994
The position looks preferable for Black, because the ♗e3 can be exchanged, and the ♘h3 is passive. With his next move, Black opens the a7-g1 diagonal, so as to bring his bishop there in the absence of its opposite number.
23…c4! 24.♗xd4
24.♗xf5 ♘xf5 25.♗b6 ♕c6
is no help – the rook is invulnerable, and the light squares begin to creak.
Since the dark-squared bishop cannot be kept from exchange, the correct decision was to get the king off the dangerous diagonal with 24.♔h1!. Admittedly, after 24…♗xe4!
(24…♘xe3 25.♕xe3 ♗c5 26.♗xb7+ ♔xb7 27.♘e4= gives White sufficient counterplay; whilst the tempting 24…♗c5? is not so successful, because of 25.♗xf5 exf5 26.b4! ♗a7 27.♖fd1∞ – White gets counterplay on the dark squares, whilst the threat of the break a2-a4 also looks quite unpleasant) 25.♘xe4 ♕c6 26.♗xd4 ♖xd4 27.♘g3 ♗c5 28.♘xf5 exf5 29.b3 ♖hd8 30.bxc4 ♖xc4 – because the ♘h3 is so far from the centre, Black still retains the advantage, but White would have chances to defend.
24…♖xd4
Not so strong was 24…♘xd4 25.♔h1 ♗c5 26.♕e1
– the knight gets in the way of its own rook.
25.♕f3
25.♗xb7+ ♕xb7 (weaker is 25…♔xb7, since in this case, the king comes under check on the long diagonal: 26.g4 ♗c5 27.♕g2+ ♖d5+ 28.♘f2 ♘e3 29.♕f3⇆, with counterplay) 26.♔h1 (26.g4 ♗c5–+) 26…♖d3 27.♘g1 ♕c6 – the bishop comes to c5 with tempo.
25…♗c5 26.♔h1
26…♖d3!
Black strives for an endgame in which his advanced queenside pawns will immediately assume great strength.
27.♗xb7+
If he avoids the exchange of queens, then after 27.♕h5 ♗xe4 28.♘xe4 ♗e3 29.♖ce1 ♕c6, Black retains a dominating position in the centre.
27…♕xb7 28.♕xb7+ ♔xb7 29.♘f2
29.♘e4 ♔c6 30.♘xc5 ♔xc5 31.♘f2 ♖e3 32.♖fd1 ♖e2 33.♔g1 ♔b4!. The activity of the king in the endgame is one of most important rules of thumb. Here, the king does not come under checks, as it would on b6, and it supports the pawns well. White will have to worry about the advance …a6-a5-a4-a3. After 34.♖b1, 34…♖f8! is even stronger than 34…a5. Black is ready also to play …g7-g5, with domination over the whole board.
29…♗xf2! 30.♖xf2 h5
With this move, Black prevents g2-g4, fixes a favourable structure, and ensures a post for his knight.
He could have played the more energetic 30…♖hd8, not fearing 31.g4 ♘e3 32.h3 b4 33.♘e4 ♔c6–+ – the passed c-pawn is close to promoting.
31.♘e4 ♔c6 32.♘g5 ♔d5 33.♔g1 ♘d4!
Closing the white’s king’s path back, and the pawn mass on the queenside ensures Black a decisive advantage.
34.♘f3 ♘xf3+ 35.♖xf3
35…♖d8!
Keeping control of the open lines is more important than spoiling White’s pawn structure. 35…♖xf3 36.gxf3 ♖f8 37.♖d1+ ♔c5 38.♖d6 b4 39.♔f2 c3 40.bxc3 bxc3 41.♔e3 ♖xf4 42.♖d7 would leave White some hopes of saving the game.
36.♖f2 ♔e4 37.♖e1+ ♔f5
Now, the white kingside pawns become objects of attack.
38.g3 b4 39.♔g2 h4! 40.♖c1 c3 41.bxc3 bxc3 42.gxh4 ♖8d4
0-1
289 ***
Mikhail Botvinnik
Mikhail Tal
Moscow Wch match 1960 (6)
Structurally, White’s position is superior, because of his possible play on the light squares. But Black’s pieces are very active, and he sacrifices a knight, so as not to be forced backwards:
21…♘f4!?
In the event of the quiet 21…♘f6 22.g4 ♗d7 23.a3 ♕b3 24.♕d2, we get a tough struggle, with a small advantage to White. Black cannot penetrate down the c-file, whilst White is ready to consolidate on the queenside, with the help of the bishop transfer f3 to d1 or e2.
22.gxf4 exf4 23.♗d2?
In the case of the immediate pawn capture 23.♗xa7, Black traps the bishop with 23…♕a5!, simply seizing the initiative.
But the intermediate move 23.a3! was strong: 23…♕b3 (if 23…♕a5 24.♗d2 ♗e5 25.f3, Black’s compensation is clearly inadequate)
analysis diagram
24.♗xa7! ♗e5 (24…b6 25.♕d1 ♕xb2 26.♖a2+–) 25.f3! b6 26.a4!. It turns out that White will play a4-a5, and rescue the bishop, since it cannot be trapped: 26…♖8c7 (26…♖4c7 27.♕b5 ♕xb5 28.axb5+–) 27.♗b8 ♖c8 28.♖a3 ♕b4 29.♘a2+–. One must of course say that it is very hard to find such a long series of only moves, and the sacrifice was fully justifiable from a practical viewpoint.
23…♕xb2?
It was correct first to force f2-f3, and shut in the ♗g2: 23…♗e5! 24.f3 ♕xb2 25.♘d1 ♕xa1! 26.♖xa1 ♗xa1 – White’s minor pieces are badly coordinated, and are going to be pinned.
24.♖ab1! f3!
24…♗xb1 25.♖xb1 ♕c2 26.♗e4 f3 (26…♖xe4 27.♕xe4 ♕xd2 28.♕e6++–) 27.♕e1 ♕xc3 28.♗xc3 ♗xc3 29.♕e3 ♖e8 30.♖xb7 ♖exe4 31.♕xf3 ♗e5+ 32.♔g2 ♖f4 33.♕e3 ♖c8 34.♖xa7 ♖cf8 35.♖a3 ♗d4 36.♕e6+ ♔g7 37.f3 ♗c5 38.♖b3 leads to a position in which White has excellent chances of realising his extra material.
25.♖xb2?
White is unable to beat the tension, and instead of retaining winning chances, he loses.
25.♗xf3! ♗xb1 (25…♗e5+ 26.♔g2 ♗xb1 27.♖xb1 ♕c2 28.♗e4 ♖xe4 29.♘xe4 ♕xb1 30.♘xd6 ♗xd6 31.♕e6+ ♔g7 32.♕d7+!+–) 26.♖xb1 ♕c2
analysis diagram
27.♗e4! ♖xe4 28.♘xe4! (28.♕xe4? ♗e5+–+) 28…♕xb1 29.♘xd6 ♖f8 30.♕e6+ ♔h8 31.♘f7+ ♖xf7 32.♕xf7 ♕f5 33.♕xf5 gxf5 34.♔g3 ♔g8 35.♗e3 ♗e5+ 36.♔f3 keeps hopes of winning the bishop ending.
25…fxe2 26.♖b3 ♖d4 27.♗e1 ♗e5+ 28.♔g1
28…♗f4
Black wins more forcingly with 28…♖xc3! 29.♖bxc3 ♖d1 30.♖c4 ♗f4! 31.♖xf4 ♖xc1 32.f3 ♖xe1+ 33.♔f2 ♖g1!–+.
29.♘xe2 ♖xc1 30.♘xd4 ♖xe1+ 31.♗f1 ♗e4! 32.♘e2 ♗e5 33.f4 ♗f6 34.♖xb7 ♗xd5 35.♖c7
35.♖xa7 ♖xe2 36.♗xe2 ♗d4+–+.
35…♗xa2 36.♖xa7 ♗c4 37.♖a8+ ♔f7 38.♖a7+ ♔e6 39.♖a3 d5 40.♔f2 ♗h4+ 41.♔g2 ♔d6 42.♘g3 ♗xg3 43.♗xc4 dxc4 44.♔xg3 ♔d5 45.♖a7 c3 46.♖c7 ♔d4 47.♖d7+
White resigned.
290 ***
Viswanathan Anand
2715
Boris Gelfand
2685
Linares 1994 (3)
The position is extremely sharp, and both kings feel unsafe. In such positions, the cost of an error is very great, and even the greatest players cannot always find the decisive continuation. Finding the winning path for Black requires colossal effort. One idea that is obvious is pinning the ♘g3 with the bishop coming to h4, whilst it is also tempting to eliminate the ♘c4, since the rook on a5 is hanging, and there is an unpleasant check at d6. However, all Black’s efforts are dealt with by the queen, which occupies a great defensive position on e3 – it pins the ♗e6 and indirectly defends the ♘g3, and is ready at the necessary moment to close the b8-h2 diagonal with the move f3-f4. The key to winning is to shift the queen from its ideal position, before making a decisive attack on the white pieces:
28…♗g5!!
In the game, there occurred 28…♖xc4 29.bxc4 ♗h4 30.♔f2 ♕xc4 (on 30…♖g5, there follows 31.f4 – this is where we see the excellent position of the queen at e3!) 31.♕d4 ♕xc2+ 32.♖d2 ♕c5 – the endgame looks equal and ended in a draw.
29.♕d3
Black wins easily after 29.♕e2 ♖xc4 30.bxc4 ♗h4 31.♔f2 ♖g5 – there is not the move f3-f4, and the ♘g3 is simply lost.
29…♖d5
A more complicated way of winning was to exploit the lethal strength of the two bishops, with the white king falling under threats from them: 29…♖xc4 30.bxc4 ♖e5+ 31.♘e4 (31.♔f2 ♗e3+ 32.♕xe3 ♖xe3 33.♔xe3 ♗xc4 34.♘e4 ♕b6+ 35.♔f4 ♗xa2 – the pawn on a3 is a decisive trump) 31…♗xc4 32.♕d4 ♗h4+ 33.♔d2 ♖d5, winning the queen.
30.♕e2 ♖xd1+ 31.♕xd1
Taking with the king allows the black queen to be included in the attack with tempo: 31.♔xd1 ♕d8+ 32.♔e1 ♕d4 33.♖g2 ♗f4 34.♘f1 ♖h1 – Black completely dominates, and has the irresistible threat of 35…♔f8, followed by 36…♗h3.
31…♖h2
The white pieces are huddled on the back rank, and can do nothing to repulse Black’s numerous threats, e.g.:
32.♕d4
Going into the endgame is no better: 32.♕d6 ♕xd6 33.♘xd6+ ♔d7 34.♘de4 (or 34.♘ge4 ♗f4) 34…♗e3 35.♖f1 ♖xc2, winning.
32…♗h4 33.f4 ♕c6!
With the irresistible threat of 34…♕f3.
Additional material
Polugaevsky-Kortchnoi, Buenos Aires match/12 1980
Gelfand-Dreev, Tilburg 1993 – Black’s 22nd move
Zhukovitsky-Geller, Moscow 1970 – Black’s 21st move
Geller-Velimirovic, Havana 1971 – White’s 14th move