GARY KASPAROV increased his lead to a massive point-and-a-half at Wijk aan Zee on Monday with an astonishing seventh straight win. Since his draw with Vassily Ivanchuk in the first round he has defeated in turn Van Wely, Yermolinsky, Topalov, Reinderman, Piket, Shirov and Kasimdzhanov to rack up 7.5/8 and an extraordinary 3,083 performance rating; and although he still had Anand Kramnik and Svidler to play

he looked overwhelming favourite to win the tournament handsomely.

In Kasparov's wake came Anand 6, Kramnik 5, Topalov and Svidler 4.5, Ivanchuk, Van Wely and Timman 4, Piket and Shirov 3.5 ; Sokolov and Yermolinsky 3, Kasimdzhanov 2 and Reinderman 1.5.

Kasparov has played many fine games, but attention is still focused on his tremendous game against Topalov that I gave on Saturday. When I originally analysed this, I believed that it was somewhat flawed and remarked that it would be "prissy" to expect "absolute soundness" in such a contest. Of course, it's not my baby and having created - with bellicose assistance from his opponent - a masterpiece, Kasparov was naturally extremely anxious to prove its soundness: both for aesthetic reasons and, even more important, to verify that his intuition was correct (see diagram).

In the game, Topalov lost beautifully after 30 ...Qc4 31 Qxf6 Kxa3 32 Qxa6+ Kxb4 33 c3+! Kxc3 34 Qa1+ Kd2 35 Qb2+ Kd1 36 Bf1 Rd2! 37 Rd7!! Rxd7 38 Bxc4 bxc4 39 Qxh8 Rd3 40 Qa8 c3 41 Qa4+ Ke1 42 f4 f5 43 Kc1 Rd2 44 Qa7 1-0 but the critical line appeared to be:

30 ...Rhe8

31 Rb6 Ra8

Now, I gave 32 Rd6 as best, probably leading to a draw, but Kasparov

Veselin Topalov (Black to play)

Gary Kasparov (White)

produced the wonderful 32 Bf1!! And with, no doubt, some help from his silicon friends, analysis to prove a win. Not only does this splendid move prevent ...Qc4 but it in many lines sets up Bxb5+ axb5 Ra7 mate.

32 ...Re1+

The best chance for White is threatening simply to capture on f6 before continuing the attack and if:

A) 32 ...Re6? 33 Rxe6 fxe6 34 Kb2 is simple.

B) 32 ...Rd8 33 Rxf6 doesn't help Black since if 33 ...Qd1+ 34 Ka2! and mates.

C) 32 ...Nh5 33 Rd6 Rec8 (or 33 ...Re1+ 34 Kb2 Qe5 35 Rd4! wins) 34 Qb2! Qxf3 35 Bd3! wins - and the same line works against 32 ...Nd7

33 Qxe1 Nd7

Apparently trapping the rook:

34 Rb7!! Qxb7

If 34 ...Ne5 35 Qc3 Qxf3 36 Bd3 Qd5 37 Be4! Qc4 38 Qxe5 etc

35 Qd1!!

But not the obvious 35 Qc3 Qd5 36 Kb2 Qe5!

35 ...Kxa3

Or 35 ...Nc5 36 c3+ Nb3 37 Kb2 etc.

36 c3! and there's no good defence to Qd1-c1-c2-a2 mate.