Chess: What am I offered for this pawn?

What is a pawn worth? Back in the late 18th century, Philidor - when not romantically describing pawns as 'the soul of chess' - reckoned they were worth around three moves each. So any gambit involving a pawn sacrifice was justified if it gained a three-move lead in development. That rate of exchange is still a fair approximation, although the difficult judgement is whether the three-move development lead is going to persist or fade away, writes William Hartston.

Today's game, from the PCA qualifier in Groningen, the Netherlands, features a remarkable pawn sacrifice in the opening by Julian Hodgson. With 9. b4, White jettisoned a pawn to draw Black's knight away from c6. If Black had instead captured 9 . . . Bxb4, then 10. Nxe5 would have been possible, since 10 . . . Nxe5 11. Rxb4 or 10 . . . fxe5 11. Bxc6+ or 10 . . . Bxc3 11. Nxc6 all regain the piece.

After 9 . . . Nxb4 10. d4] White's idea is that 10 . . . exd4 11. Nxd4 c5 12. Ndb5 is profoundly uncomfortable for Black, whose Q-side comes under intense pressure. As the game went, Hodgson gained two moves for the pawn (the time taken for Black's knight to take and retreat), but more importantly he isolated the black e-pawn and left Black's king in the centre, thanks to his control of the b3-g8 diagonal. Altogether it added up to more than enough, but it took good judgment (and courage) to appreciate how difficult Black's problems are to solve.

When White threatened mate with 16. Qa3, he must have felt that the sacrifice was working, but the key move was 19. Bxd4] After 19 . . . exd4 20. Ne4 White threatens Nd6 as well as capturing on c5. Polgar took with the other pawn but Hodgson's 22. Bxb7 forced decisive material gain. After 22 . . . Rb8 White has 23. Nc6 and the exchange is lost anyway.

----------------------------------------------------------------- White: Julian Hodgson ----------------------------------------------------------------- Black: Zsuzsa Polgar ----------------------------------------------------------------- 1 c4 e5 16 Qa3 c5 2 Nc3 Nf6 17 Rbc1 h6 3 Nf3 Nc6 18 Be3 0-0 4 g3 d5 19 Bxd4 exd5 5 cxd5 Nxd5 20 Nd5 Qd8 6 Bg2 Nb6 21 Ne7+ Kh8 7 0-0 Be7 22 Bxb7 Bh7 8 Rb1 f6 23 Bxa8 Qxa8 9 b4 Nxb4 24 Qd6 Qe8 10 d4 Nc6 25 Rc7 Na4 11 dxe5 fxe5 26 Rc8 Qxc8 12 Qb3 Bf5 27 Nxc8 Rxc8 13 Rd1 Qc8 28 Qa6 Nb6 14 Ng5 Bxg5 29 Qxa7 1-0 15 Bxg5 Nd4

And for dessert, here is the finish of Hebden-Sadler from the second round at Hastings:

In the diagram position after 36 moves, with Matthew Sadler (Black) short of time, Mark Hebden realised that all he had to do was get rid of his e-pawn and he could win the game immediately. So he set a neat trap: 37. Bd2] Qxe5? 38. Bc3 Qd5 39. Qh7+ Kf8 and now it is mate in two with 40. Qh8+] Bxh8 41. Rxh8 mate. Of course Black did not want to lose his g-pawn for nothing after 37. Bd2 so he grabbed at the pawn on e5, but once the bishop had returned to the long diagonal there was no defence. Such a pawn sacrifice is not so difficult. `