Chess

WHEN you run out of potentially useful pawn moves, you are strategically dead. Forgetting this basic rule was what led to Bobby Fischer's defeat in the 12th game of his match with Boris Spassky on Wednesday.

The opening was the same as in game 8: (Spassky is White) 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 0-0 6. Be3 Nc6 7. Nge2 a6. In the earlier game, play went 8. Qd2 Rb8 9. h4 h5 10. Bh6 e5 11. Bxg7 Kxg7 12. d5 Ne7 13. Ng3 c6 with active play for Black. This time Spassky varied with 8. h4.

Apparently viewing this as a harmless transposition, Fischer continued with 8 . . . h5 9. Nc1 e5 10. d5 Ne7 but there is a world of difference. With black- squared bishops exchanged, it makes sense for Black to have pawns stuck on d6 and e5; now they stifle the bishop on g7. The knight on e7 is another problem. Usually in such King's Indian positions, Black relies on being able to play f5, f4 and g5, when the knight emerges on g6, but with the h-pawns moved, that becomes difficult.

Spassky's next few moves showed great insight into the position: 11. Be2 Nh7 12. Nd3] f5 13. a4] Nf6 14. Nf2] Black is stifled on both wings. If he plays fxe4, White recaptures on that square with his knights, when the pawn on g6 becomes a severe weakness on the diagonal from b1. If he plays f4, White has every prospect of opening the g-file later with g3. With Black's b5 firmly stopped by a4, and White threatening to gain more space by playing a5 himself, Black has run out of good pawn moves and run out of ideas. Meanwhile, White still has the pawn break with g4.

Fischer decided to seal one wing with 14 . . . a5 15. Qc2 c5 16. 0-0-0 b6, but after 17. Rdg1 Nh7 18. Nb5 Kh8 19. g4] he was already strategically lost.

He never made such judgmental errors 20 years ago.

Yesterday's answer: 1. Bg5] and there is no good reply to the threat of Bxe7 mate.