去九法 (Casting out nines)

Arkadij Mikhailovich Naiditsch – Ankit Rajpara
1st Qatar Masters Open; Doha, November 26, 2014
Caro-Kann Defence B12

1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3 e6 5. Be2 Ne7 6. 0-0 Bg6 7. Nbd2 Nf5 8. c4 Be7. If 8. ... Nd7 there might follow 9. cxd5 cxd5 10. Nb3 as in the game Zhigalko – Dreev, International Chess Festival “Baku Open”, Baku 2013. 9. g4 Nh6. The strategic alternative was 9. ... Nh4 10. Nxh4 Bxh4 11. f4 f5!? with chances for both sides. 10. h3 Ng8. A truly undeveloping manoeuvre. 11. Ne1 h5 12. Ng2 hxg4 13. hxg4 dxc4 14. Nxc4 Be4 15. f3 Bd5 16. Nce3 c5 17. Nf4 Bc6 18. d5 exd5 19. Nfxd5 Bh4. Intending ... Bh4-g3. 20. Kg2. In order to stop ... Bh4-g3, but there is a terrible shock coming. Simply 20. Nf4 (Δ e5-e6) would have ensured White a distinct advantage.

20. ... Bg3!! Anyway! 21. Kxg3? Bad judgment. The casting out nines was 21. Nf6+! gxf6 22. Qxd8+ Kxd8 23. Kxg3 with some edge for White. 21. ... Qh4+ 22. Kf4 Qh2+ 23. Ke4 Nd7. Intending both ... Nd7xe5 and ... 0-0-0. 24. Kd3. After 24. f4? 0-0-0 White is doomed. 24. ... 0-0-0 25. Kc2 Nxe5 26. Qd2? The only chance to defend was 26. a3 Kb8. The text exposes His Majesty to a furious assault. 26. ... Nf6 27. Ne7+ Kb8 28. Nxc6+ Nxc6 29. Bd3 Nb4+ 30. Kb1 Qc7 31. g5 Rxd3 32. Qe1 Nfd5 33. Ng4 Nb6 34. Qe5 Qxe5 35. Nxe5 Rd4 36. Nxf7. This loses instantly. On 36. Be3 Rd5 Black stands much better. 36. ... Rh2 37. Be3. Equally hopeless was 37. a3 Nd3. 37. ... Nd3 38. Bc1 Nc4. 38. ... Rc4! was an even quicker way to win, threatening 39. ... Rxc1+ 40. Rxc1 Rxb2 mate. 39. Rd1 Nxc1 0 : 1.