The super-grandmaster tournament in Dortmund has turned into a race between Vladimir Kramnik and Anatoly Karpov. After six rounds, with three left to play, Kramnik leads with 5 points, and Karpov, who has just scored two wins in a row, is breathing down his neck on 41/2.

While Karpov has been patiently cultivating small advantages and grinding out slow wins, Kramnik has been playing some brilliantly aggressive chess. In round five, he gave Nigel Short no chance at all.

White's order of moves in the opening, with 5.Qc2 in place of the usual 5.Bg5, is designed to make it more difficult for Short to adopt his favourite plan with b6 and Bb7. After 8...b6, White would play 9.e4, opening the game to his advantage.

Instead, Short adopted a solid, though passive formation, which Kramnik assaulted with 12.h4! and the crude but effective a3, Ba2 and Bb1. After that, the threat of h5 became serious, and forced Black to advance his own h-pawn.

With his rook no longer needed on the h-file, Kramnik finally castled, put his knight on the newly won g5 square and brought his bishop back to its most effective diagonal. After 18.Ba2, Black ought to sit his knight on f8 and wait for the attack to break, but Short let his knight wander off to g4 instead.

Perhaps he had been relying on 23...Nxe5 to save him from White's well- prepared 22.Bxe6! sacrifice, but after 24.Qh7+ and 25.Nf4 he was helpless against the threats of N4xe6+ or dxe5 followed by Ng6+.

White: Vladimir Kramnik

Black: Nigel Short

1 Nf3 d5 14 Ba2 b6

2 d4 Nf6 15 Bb1 h5

3 c4 e6 16 0-0 Bb7

4 Nc3 Be7 17 Ng5 Rfd8

5 Qc2 0-0 18 Ba2 Nf6

6 Bg5 h6 19 e4 Ng4

7 Bxf6 Bxf6 20 e5 Rd7

8 Rd1 g6 21 Ne2 Rad8

9 e3 c6 22 Bxe6 fxe6

10 Bd3 dxc4 23 Qxg6 Nxe5

11 Bxc4 Nd7 24 Qh7+ Kf8

12 h4 Bg7 25 Nf4 1-0

13 a3 Qe7

In the next round, Kramnik showed his willingness to take risks with Black. Playing a sharp Sicilian line against Peter Leko, he launched some highly provocative tactics with 7...f5!? when 8.exf5 Bxf5 invited the position reply 9.Bg4 or the move that Leko chose, 9.Bg5.

With 9...Bxg5 losing to Nxd6+ and Nxf5, Kramnik was forced into a radical solution with 9...a6 and 10...Kxe7! A further tactical flurry saw Black give up his queen for two rooks, after which the players, with a roughly level game, agreed they had had enough excitement, though the final position is far from dead.

White: Peter Leko

Black: Vladimir Kramnik

1 e4 c5 12 0-0 Qb6

2 Nf3 Nc6 13 b3 Rhd8

3 d4 cxd4 14 Bd3 Be6

4 Nxd4 e5 15 Be4 Qd4

5 Nb5 d6 16 Qe2 Nxe4

6 c4 Be7 17 Nxe4 Qxa1

7 Be2 f5 18 Nbc3 Nd4

8 exf5 Bxf5 19 Qd2 Qxf1+

9 Bg5 a6 20 Kxf1 h6

10 Bxe7 Kxe7 21 Ne2 Nxe2

11 N5c3 Nf6 22 Kxe2 draw