A few days ago, this space contained a splendid game in which John van der Wiel demolished a strong computer program. His winning technique was to play cramped and uninspiring chess of exactly the type that machines cannot understand. Give them nothing to calculate, and they will drown in their own megabytes.

The counter-argument, however, is that any positional nuance - a weak square, a vulnerable king, a lack of space or whatever - will ultimately become susceptible to tactical exploitation. A machine need not understand strategic subtleties if it can calculate far enough ahead.

Until recently, it seemed that silicon thought would not be able to make that dream come true. Even the fastest computers could not cope with the billions of possibilities needed to compensate for a lack of strategic understanding. As the following game shows, however, our anthropocentric intellectual smugness is coming under severe threat.

White's 12.h4! is just the sort of move computers are not meant to be able to find. The pointless dithering that preceded it, with 9.Be3, 10.Be2 and 11.Bd3, is far more what we are used to, yet 12.h4 brilliantly seizes on the only potential weakness in Black's position. The only way a machine can have decided on such a move is to have stumbled on it through an exhaustive analysis. By looking at every legal possibility to a depth of three moves (comprising about a million positions) it must have got as far as 14.h6! and decided it was worth a fling. After 14...Nxh6, White plays 15.Nxg5! fxg5 16.Bxg5, while 14...Bxh6 is met by 15.exd5 cxd5 16.Rxh6! Nxh6 17.Nxg5 with a winning attack.

16.Nxd5! is the sort of opportunity a computer does not miss: 16...exd5 loses to 17.Bxh7+! Kxh7 18.Qd3+ Kg8 19.Qg6+. The final attack, beginning with 18.Rh5! and 19.Bxg5! is most impressive.

White: QUEST

Black: John Nunn

Aegon "Man v Machine" 1995

Pirc Defence

1 e4 g6 18 Rh5 Rf7

2 d4 Bg7 19 Bxg5 Bxf3

3 Nc3 c6 20 gxf3 fxg5

4 Nf3 d5 21 Rxg5+ Kf8

5 h3 Nh6 22 Rdg1 Nf6

6 Bf4 f6 23 Ne4 Ndxe4

7 Qd2 Nf7 24 fxe4 Qxd4

8 0-0-0 0-0 25 e5 Ke7

9 Be3 a6 26 c3 Qb6

10 Be2 b5 27 exf6+ Bxf6

11 Bd3 e6 28 Rg8 Rxg8

12 h4 Nd7 29 Rxg8 Bh4

13 h5 g5 30 f4 Bf2

14 h6 Bh8 31 Kc2 Qe3

15 exd5 cxd5 32 Qd1 Qxf4

16 Nxd5 Bb7 33 Bxb5 Bb6

17 Nc3 Nd6 34 Be8 resigns