What would happen if we told the rules of chess to a really clever computer? Not a feeble little billion-moves- a-second Deep Blue sort of thing, but something more intelligent? There would be no need for programming; it would just look at the rules and work things out for itself.

Queens and rooks would pose it no problems. Then it would work out the cumbersome geometry of knight-space and the problems of pawn structure. The bishops, however, would really give it something to think about.

And after thinking about it, our super-computer might well decide that, since any bishop stands on two diagonals, and one is shorter than the other, its longer diagonal should be as long as possible.

So after a great deal of thought, it will open 1.b3!! to ensure that its bishop grabs the long diagonal before the opponent's can get there.

If you don't believe it, look at the following game played in Poland in 1935. Tartakower, being not quite as clever as our machine, did not play b3 until move nine, but the bishop on b2 won the game. Black's 10...d5 seems to block it out of the game, but after 12.Rac1 Black faces a dilemma. If he keeps his pawn on d5, White will squash him on the Q-side with c5, a3, b4 and a systematic advance of the pawn majority. In the meantime, Black's own majority in the centre is firmly held up by the pawn on d4 and the bishop lurking behind it on b2 which make expansion with ...e5 almost impossible.

So Najdorf felt that that 13...dxc4 was the lesser of the evils, at least avoiding the cramped position that would afflict him if White played c5. But it left the white d-pawn free to advance and unleash the bishop with 18.d5!

After 18...exd5 19.Bf5 Black would be in a terrible mess, though little worse than what happened. The bishop, of course, had the last word, with 21.Bxf6! winning on the spot. After 21...gxf6 22.Nh6, the threats of Nf7 mate and Qg8 mate are decisive.

White: Savielly Tartakower

Black: Miguel Najdorf

1 d4 Nf6 12 Rac1 Bb4

2 Nf3 b6 13 a3 dxc4

3 e3 Bb7 14 bxc4 Bxf3

4 Bd3 c5 15 Qxf3 Na5

5 Nbd2 e6 16 Qe3 Nd7

6 0-0 Be7 17 Ne5 Re8

7 Re1 cxd4 18 d5 Nf8

8 exd4 0-0 19 Qg3 f6

9 b3 Nc6 20 Ng4 Kh8

10 c4 d5 21 Bxf6 1-0

11 Bb2 Rc8