Backdoor

Alexandra Konstantinovna Kosteniuk – Mariya Muzychuk
5th Women’s World Chess Team Championship; 成都市 (Chéngdū), April 27, 2015
Spanish C81

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. 0-0 Nxe4 6. d4 b5 7. Bb3 d5 8. dxe5 Be6 9. Qe2 Be7 10. Rd1 0-0 11. c4 bxc4 12. Bxc4 Bc5 13. Be3 Bxe3 14. Qxe3 Qb8 15. Bb3 Qb6 16. Qxb6 cxb6 17. Na3 Nc5. This looks to be a theoretical novelty by Mariya Muzychuk. If 17. ... Rfd8 might follow 18. Nc2 Na5 19. Ncd4 (if, instead, 19. Nb4 then 19. ... Nc4 20. Bxc4 dxc4 21. Nxa6 Rxd1+ 22. Rxd1 h6 23. Nb4 Ra4 24. a3 c3 25. bxc3 Rxa3 26. h3 Rxc3 27. Rd8+ Kh7 28. Rb8 Bxh3 29. Rxb6 Be6 30. Nd4 Rc1+ 31. Kh2 Nxf2 32. Nxe6 fxe6 33. Rxe6 h5 34. g3 Rb1 35. Nd5 Rb2 36. Rb6 Re2 37. Nf4 Ng4+ 38. Kg1 Rxe5 39. Kg2 Nf6 0 : 1 Tukmakov – Kortschnoi, 41st USSR Chess Championship, Moscow 1973) 19. ... Nc4 20. Rab1 Rac8 21. h3 h6 22. Re1 Nc5 23. Bc2 Bd7 24. Re2 Re8 25. b3 Na3 26. Rd1 Bb5 27. Re3 Nxc2 28. Nxc2 Nxb3 29. Na3 Rc1 30. Rde1 Rxe1+ 31. Rxe1 Nc5 32. Nxb5 axb5 33. Rb1 Ra8 34. Rxb5 Rxa2 35. Rxb6 Ra1+ ½ : ½ B. Ivanović – Timman, Belgrade 1987. Also playable is furthermore 17. ... Nb4 18. Nc2 Nxc2 19. Bxc2 Rac8 20. Nd4 a5 21. a3 Rc4 22. f3 Nc5 23. Rd2 g6 24. Kf2 Rc8 25. Ke3 Nd7 26. f4 Nb8 27. Rad1 h5 28. h3 Nc6 29. Bb3 Nxd4 30. Rxd4 Rxd4 31. Kxd4 a4 32. Ba2 Rc2 33. Bxd5 Bxd5 34. Kxd5 Rxb2 35. g4 hxg4 36. hxg4 b5 37. f5 gxf5 38. gxf5 b4 ½ : ½ L. Schmid – Pachman, Pula 1988. 18. Bxd5 Bxd5 19. Rxd5 Rfd8 20. Rad1 Rxd5 21. Rxd5 Nb4 22. Rd4 Nxa2 23. Nc4 b5 24. Nd6. Even 24. Nb6 Re8 25. Nd7 Nxd7 26. Rxd7 Nb4 wouldn’t lead to anything special for White. 24. ... Nc1 25. Kf1 Ne6 26. Rd1 Nb3 27. Nd2 Nbc5 28. N2e4 Nxe4 29. Nxe4 Rc8 30. g3 h6 31. Rd2 Rc4. Also worth considering is 31. ... Ng5 32. Nxg5 hxg5 33. Ke2 Rc4 with equality. 32. Nd6 Rc1+ 33. Ke2 g5 34. Ne4 Kg7 35. Kf3 Re1 36. g4 h5 37. h3 h4 38. Rd6 a5 39. Rd5 b4 40. Nd6 a4 41. Nf5+ Kg6 42. Ra5 Ra1

43. Ke4. After 43. Rb5 Black might offer a temporary Pawn sacrifice by 44. ... a3! 44. Rxb4 a2 45. Ra4 Nc5 46. Ra3 Nd7!, in order to gain a dynamic advantage. 43. ... b3 44. Ne7+? White’s King ought to move towards the Queenside to put a stop to the enemy Pawns: 44. Kd3! and if 44. ... a3 then 45. Rxa3 Rxa3 46. bxa3 Nf4+ 47. Kc3 Nxh3 48. f3 Ng1 49. Kxb3 Nxf3 when the chances of a draw would be extremely high. 44. ... Kh7 45. Nd5 Kg7 46. Nc3 Ra2. Probably best is 46. ... a3! as after 47. Rxa3 (47. bxa3 Rh1 is equally hopeless) 47. ... Rxa3 48. bxa3 Nf4 Black would have secured excellent winning chances. 47. Ke3 Rxb2 48. Rxa4 Rc2. Black misses her last chance: 48. ... Nf4! and if 49. Ra7 (49. Rb4 Nxh3 doesn’t look any better) then 49. ... Rc2 50. Ne4 Re2+ 51. Kf3 Re1! 52. Nxg5 Nd3! and Black must win. 49. Ne4 Rc1 50. Rb4 Re1+ 51. Kd2 Rb1 52. Nd6 Nc5 53. Nf5+ Kh7 54. Rb5 Ne4+ 55. Ke3 b2 56. Kxe4 Re1+ 57. Ne3 b1=Q+ 58. Rxb1 Rxb1 59. Kf5 Rh1 60. Kxg5 Rxh3 61. Nf5 Rh2 62. Nxh4 Rxf2 63. Nf5 Kg8 64. Kf6 Rg2 65. e6 fxe6 66. Kxe6 Kh7 67. Kf6 Rxg4 68. Ne3 Rg6+ 69. Kf5 Kg7 70. Nd5 Ra6 71. Ke5 Kf7 72. Nf4 ½ : ½.

Alexandra Konstantinovna Kosteniuk vs. Mariya Muzychuk
Photo: Liu Yupeng