1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. f4 Bg7 8. Bb5+ Nfd7 9. Bd3 Qh4+ 10. Kf1 Na6 11. Nf3 Qd8 12. Kf2 Qb6 13. Kg3 Nb4 14. h3 Nxd3 15. Qxd3 Qa6 16. Qxa6 bxa6 17. e5 O-O 18. exd6 Rb8 19. Re1 Rb6 20. Nd2 Nf6

Something has gone badly wrong for Portisch and now with the straightforward (20... Nf6 ) 21. Nc4 Rb4 22. Na5 ( or 22. Ne5) White stands much better. Unfortunately Tomson takes the time for a preparatory move, apparently based on a miscalculation.

21. a3?! Nh5+ 22. Kf3 Rxd6 23. Nde4 Bxc3 24. bxc3?!

24. Nxc3 still leaves White a little better.

24... Rxd5 25. g4?

The final error. After 25. Be3 White is still in the game, though any advantage is long gone.

25... f5!

Was this what Tomson missed earlier? Now White is in serious trouble. Portisch converted without further incident.

26. Nf2 fxg4+ 27. hxg4 Nxf4 28. Bxf4 g5 29. Re4 Bb7 30. Ke2 gxf4 31. Re7 Rf7 32. Rxf7 Kxf7

0-1

Annotator(s): Seán Coffey (see reference).

Source(s): Big Database 2012.

Reference(s): Seán Coffey and David McAlister, "Brian Tomson 1942-1986", Irish Chess Journal, August 2011, pp. 14-16 and IRLchess, September 29, 2011.