Not Yet Goodbye

Roberto Cosulich – Roman Shlemovich Pelts
15th International Festival; La Spezia, March 1978
Sicilian Defence B82

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 d6 6. f4 Nc6 7. Be3 a6 8. Qf3 Qc7 9. Bd3 Bd7 10. Nb3. Alternatively, 10. 0-0-0 Rc8 11. h3!? b5 12. Kb1⩲ gives White slightly better chances, Sax – 叶江川 (Yè Jiāngchuān), 1st World Team Chess Championship, Lucerne 1985.
10. ... Na5? This time-wasting move is a harbinger of trouble for Black. If anything, the Knight should move to b4.
11. 0-0 Nc4 12. Bxc4 Qxc4 13. e5 Bc6 14. Qh3 Nd5 15. Na5 Qb4 16. Nxc6 bxc6 17. Nxd5 cxd5 (17. ... exd5 18. e6!)
18. f5! dxe5 19. fxe6 f6

20. Qh5+? White could and should take advantage of the Black King still in the centre with 20. c4!!, in order to open either the c- or the d-file. Apparently Black has no satisfactory reply, for if 20. ... Qxc4 then 21. Rac1 followed by the invasion to the seventh rank; if, instead, 20. ... dxc4 there would follow 21. Qh5+! g6 22. Qf3 with too many threats. On the other hand, the attempt to keep the files closed with 20. ... d4 fails to 21. Qh5+! Kf8 (21. ... g6 22. Qf3) 22. Bxd4! with an overwhelming initiative.
20. ... g6 21. Qf3 Be7. 21. ... Bc5 22. Rae1 0-0 23. Qxd5 Bxe3+ 24. Rxe3 Rad8 was also playable.
22. Qxd5 0-0

23. Rxf6! Cosulich tries his way by a spectacular Exchange sacrifice which, at least from a psychological perspective, is hardly separable from its practical justification.
23. ... Rfd8. Black cannot take the Rook at once, either with 23. ... Rxf6 (because of 24. Qxa8+) or 23. ... Bxf6 (on account of 24 e7+).
24. Qxe5 Bxf6 25. Qxf6 Rf8 26. Qd4 Qxd4 27. Bxd4 Rf4? This is the losing move. After 27. ... Rfe8! 28. Re1 Rac8 Black should somehow hold to the end.

28. Bc5! Of course, Cosulich didn’t miss the point, as the e6-Pawn is worth a treasure! The rest is a matter of technique.
28. ... Rc4 29. Ba3 Rxc2? Wins back a Pawn, but hastens the end. On the other hand, after 29. ... Re8 30. e7 Kf7 31. Rf1+ Ke6 32. Re1+ Kf7 33. c3 Black could not save the ending in any case.
30. Rf1 Kg7 31. e7 Rg8 32. Rf8 Re2 33. Kf1 Re6 34. b3 h5 35. h4 Kh7 36. Kf2 a5 37. Kf3 Re1 38. Bc5 Re6 39. a3 Re5 40. b4 axb4 41. axb4 Re6 42. b5 g5 43. b6 gxh4 44. Rxg8 1–0. For after 44. ... Kxg8 45. b7 the b-Pawn queens.