The game that gave Matthew Sadler the British Championship last week was lost and won in a single move. Jonathan Levitt could be excused for kicking himself for his move in the diagram position (right). The point was that after 23...Qe6? 24.Bc7! any move of the rook from d8 is met by Bxb6, winning either the a-pawn or d-pawn. And Black's losses did not stop there. After 24...Rda8 25.Bxb6 Rxb6 (25...Qxb6 26.Nxd5 is no better) 26.Nxa4, Black's c-pawn is also dying. 26...Rxa4 was the only slim chance to fight, but once White had avoided the trap of 29.exd4? Qa2, Black had little hope.

Sadler may reasonably claim that the blunder was the result of his fine strategy, designed to make the best of the black-squared bishop.

19.Nc3! was a particularly fine move, inviting 19...Qxe3+ 20.Bf2 Qe7 21.Rfe1 when either Qd6 or Qc7 is met by Nb5 regaining the c-pawn with advantage. Here are the full moves:

White: Sadler Black: Levitt

1 d4 Nf6 24 Bc7 Rda8

2 c4 e6 25 Bxb6 Rxb6

3 Nc3 Bb4 26 Nxa4 Rxa4

4 Qc2 0-0 27 Qxa4 Rxb2

5 a3 Bxc3+ 28 Qa5 d4

6 Qxc3 b6 29 Rd2 Rb3

7 Bg5 Bb7 30 Qxc5 Rxe3

8 f3 c5 31 Rf1 d3

9 dxc5 bxc5 32 Qd4 Nh5

10 e3 a5 33 Rxd3 Re2

11 Bd3 a4 34 Rd2 Nf4

12 Ne2 d6 35 Kh1 Re1

13 0-0 Nbd7 36 Qf2 Re3

14 Qc2 h6 37 Ra1 Nd3

15 Bf4 Qe7 38 Qf1 Nc5

16 Rad1 d5 39 Rdd1 Nb3

17 Bg3 Nb6 40 Rab1 Qf5

18 cxd5 exd5 41 Qf2 Rc3

19 Nc3 Rfd8 42 Qb6 Nc5

20 Rfe1 Ba6 43 Qxh6 f6

21 Bxa6 Rxa6 44 Rb8+ Kf7

22 Bh4 g5 45 Qh5+ 1-0

23 Bg3 Qe6