Here's a splendid position to try on your computers:

It is White to play, though that does not matter much, and Black is a bishop and a pawn ahead, which doesn't matter at all. A quick inspection should be enough for any human to realise that Black's rook and bishop are permanently entombed and will play no further part in the game. Meanwhile, White wins on the K-side with what is effectively an extra rook. Computers, however, have a problem with the concept "never" and the true plight of Black's Q-side is likely to be lost on them.

Such positions have frequently been produced by computer-hostile humans to demonstrate the limitations of machine thought, but the one above comes from a variation spotted by Garry Kasparov in a game he won in Amsterdam over the weekend.

The event, which is still in progress, is a four-man, six-round tournament in which Kasparov faces three promising young grandmasters: Joel Lautier (France), Jeroen Piket (Netherlands) and Veselin Topalov (Bulgaria). Here's the game that almost produced the magic position:

White: G. Kasparov

Black: J. Piket

1 e4 e5 16 Qxa1 0-0

2 Nf3 Nc6 17 e5 Qc5

3 Bc4 Bc5 18 Rc1 c6

4 b4 Bb6 19 Ba2 Qa3

5 a4 a5 20 Nb6 d5

6 b5 Nd4 21 Nxa8 Kh8

7 Nxd4 Bxd4 22 Nb6 Be6

8 c3 Bb6 23 h3 Rd8

9 d4 exd4 24 bxc6 bxc6

10 0-0 Ne7 25 Rc3 Qb4

11 Bg5 h6 26 Rxc6 Rb8

12 Bxe7 Qxe7 27 Nxd5 Qxa4

13 cxd4 Qd6 28 Rc1 Qa3

14 Nc3 Bxd4 29 Bc4 resigns

15 Nd5 Bxa1

The Evans' Gambit ought to have been no surprise - Kasparov used it a couple of weeks ago to demolish Viswanathan Anand - but Piket's reply, declining it, then grabbing an even hotter pawn a few moves later, looked like poor improvisation.

4...Bb6, quite apart from being a snivellingly evasive way to treat a gambit, has never had a good reputation. White immediately gains useful space on the Q-side. Piket's 13...Qd6, however, was asking for trouble.

Kasparov played 14.Nc3! almost without thought. "I was sure I was winning," he said after the game. "Just how, I was going to find out."

Later he demonstrated the variation 14...Qxd4 15.Nd5! Qxc4 16.Nxb6 cxb6 17.Qd6 Qe6 18.e5 Qxd6 19.exd6 Kd8 20.Rfe1 Re8 21.Rxe8+ Kxe8 bringing us back to the diagram position. After that splendid fantasy, the rest of the actual game is almost an anticlimax.

Kasparov looked hard for a win with 20.Rc3 Qxa4 21.Ne7+ Kh8 22.Rg3, but finally opted for 20.Nb6, when the double threat of Nxa8 and Bxf7+ wins a rook. White must only check that the knight has a safe escape route, which Kasparov demonstrated with his usual accuracy.

Ater two rounds in Amsterdam, Kasparov and Topalov share the lead with 11/2 points each.

William Hartston