Commentary - 2013 U.S. Championships, Round 6

In round 6 the last perfect score in the championships dropped, as the women's leader Irina Krush was held to a draw as Black by Sabina Foisor.  For me the most relevant game was Baginskaite-Zatonskih, another Modern Stonewall reached via the Slav move-order along the lines of Zatonskih's round 2 game.

In this game, Baginskaite seems better prepared in general against the Stonewall and must have had some expectation that Zatonskih would go into this line again.  Black nevertheless equalizes easily and holds at least some initiative throughout the game, although White manages to cleverly avoid some lurking Black threats in the early middlegame.  The inflection point of the game occurs on move 26 after a lengthy tactical sequence, where Black reveals a back-rank mate threat that prevents a White pawn recapture and gives her a lasting material advantage.  Black's road to the victory is still quite difficult, however, and White for a long time succeeds in placing various obstacles in her opponent's way.

[Event "2013 U.S. and Womens' Championship"] [Site "Saint Louis, Missouri, USA"] [Date "2013.05.09"] [Round "6.16"] [White "Baginskaite, Camilla"] [Black "Zatonskih, Anna"] [Result "0-1"] [ECO "A84"] [WhiteElo "2278"] [BlackElo "2466"] [Annotator "ChessAdmin/Houdini"] [PlyCount "156"] [EventDate "2013.??.??"] [TimeControl "6000+1285"] [WhiteClock "0:01:40"] [BlackClock "0:02:34"] 1. d4 d5 2. c4 c6 3. Nf3 e6 4. e3 f5 5. Bd3 Nf6 6. O-O Bd6 7. b3 {Unlike in the round 2 game, White goes for a more standard plan against the Stonewall. The text move prepares Ba3 and an exchange of the Bd6, which would leave Black with a weak dark-square complex. Black's next move is designed to prevent this. } Qe7 8. Qc2 O-O 9. Ne5 {there is a wide variety of moves played here, but occupying e5 with a knight is a standard idea for White.} b6 10. Bb2 {a reasonable move but a new one nonetheless, according to the database.} Bb7 { this development of the light-square bishop is a feature of the Modern Stonewall and is now more popular than the old transfer of the bishop to h5. On b7, the bishop appears buried, but serves a useful function supporting the c-pawn and can spring to life if it advances and pawn exchanges occur in the center.} 11. cxd5 Nxd5 12. a3 Nd7 13. Nd2 Rac8 14. Ndc4 Bb8 {Houdini favors this retreat, which preserves the valuable bishop.} 15. Qe2 c5 {now the Bb7 looks quite strong.} 16. Nxd7 {exchanging the nicely posted Ne5 for the Nd7 seems counterintuitive, but is in fact a common idea in the Stonewall, in part because White can reposition her other knight to e5 later on. White starts to have problems in this position if this does not occur, as examined in the following sample variation. Black has a number of tactical possibilities lurking, with ideas including using her Nd5 for forks on c3 or f4, along with the two powerful bishops pointed at White's king.} (16. Rad1 cxd4 17. Bxd4 { recapturing with the e-pawn would allow ...Nf4, attacking the Qe2 and g2 simultaneously.} Nxe5 18. Nxe5 Nc3 19. Bxc3 Rxc3 20. f4 Bd5 (20... Rxb3 $2 21. Bc4) 21. b4 Bb3 $17) 16... Qxd7 17. dxc5 Rxc5 (17... Qc6 {is an interesting idea.} 18. f3 (18. cxb6 $2 Nf4 19. Qf3 Qxf3 20. gxf3 Nxd3) 18... Qxc5) 18. Rac1 Rd8 19. Rfd1 {White has avoided Black's nastier ideas through her earlier exchanges and is in a better position to fight for the center and d- and c-files. The position is evaluated as equal by Houdini.} Rcc8 20. Ne5 Qe7 { Black chooses to maintain her longer-term chances rather than exchange off the new Ne5.} (20... Bxe5 {would start a long, largely forced line leading to an equal endgame.} 21. Bxe5 Rxc1 22. Rxc1 Nxe3 23. Rc7 Qxd3 24. Rxg7+ Kf8 25. Qxd3 Rxd3 26. fxe3 Bd5 $11) 21. Ba6 {the key error, according to Houdini. Perhaps White did not see Black's move 24 or, more likely, the back-rank threat revealed on move 26. White needs to avoid the deflection tactic that gains Black the a-pawn.} (21. Rxc8 Rxc8 22. Nf3) (21. b4) 21... Rxc1 22. Rxc1 Bxe5 23. Bxe5 Qxa3 24. Ra1 Bxa6 25. Qxa6 Qxa6 26. Rxa6 Nb4 {White's back-rank weakness, exposed by Black's last move, prevents her from taking Black's a-pawn.} 27. Ra1 Rd3 28. Kf1 Nc6 29. Bc7 Rd7 (29... Rxb3 {was likely avoided by Black due to the extra activity it allows White's pieces. Houdini evaluates both this variation and the text move equally. It might have been easier for Black to simply take the material, however.} 30. Rc1 Ne7 31. Be5 Rb5 32. f4 Nd5 $17) 30. Bg3 Kf7 31. Rc1 Nb4 32. Ke2 e5 33. f3 (33. Bxe5 $2 Nd3) 33... Ke6 34. Rc8 Nd5 35. Re8+ Re7 36. Rc8 f4 {White's rook cannot make any meaningful threats, so Black decides to make some progress on the kingside.} 37. Bf2 Kd7 38. Ra8 Kc6 {Black is transferring her king to the main theater of action on the queenside, where it is needed to support an eventual pawn advance.} 39. e4 Nb4 40. Be1 Kb5 41. Bc3 Nc6 42. Kd3 Kc5 43. Rc8 Rd7+ 44. Kc2 {White has been doing well in placing obstacles in front of Black's queenside advance.} Kd6 45. b4 b5 {necessary to fix the b4 pawn in place. Black will now aim to force through ...a5 in the long run.} 46. Kb3 Rb7 47. Rh8 h6 48. Rc8 Rc7 49. Rg8 { exchanging rooks would leave White with simpler problems to solve in the endgame.} Ke6 50. Re8+ Re7 51. Rc8 Kd7 52. Rg8 Kc7 53. Rf8 Kb6 54. Ra8 Kb7 { both sides continue to focus on the queenside struggle. After the text move, Houdini considers the position equal.} (54... Re6 {is pointed out by Houdini, which would go after White's abandoned kingside pawns after the follow-up ... Rg6.} 55. g3 fxg3 56. hxg3 Rg6 57. g4 Rf6 58. Rg8 Rxf3 59. Kc2 $17 (59. Rxg7 $2 Nxb4 60. Rg6+ Kc5 61. Re6 Nc6 62. Kb2 Rf2+ 63. Kb1 Rf4 $19)) 55. Rf8 $11 Kc7 ( 55... Re6 {no longer works due to} 56. Rf7+) 56. Rg8 Kd7 57. Rf8 Kd6 58. Rg8 Rb7 59. Rc8 a5 {Black decides to stop dancing around with the rooks and force the issue.} 60. bxa5 b4 61. a6 Rb6 62. Bd2 {allows Black to make progress.} ( 62. Bb2 {would add another blockader to the b-file.}) 62... Rxa6 {now White faces an uphill battle, being down material and with Black's rook dominant on the a-file.} 63. Rg8 Ra3+ 64. Kc4 Ra2 65. Bxb4+ Nxb4 66. Kxb4 Rxg2 {classic endgame strategy, liquidate in one area in order to transfer your advantage to another.} 67. Kc4 h5 68. h4 Rg3 69. Rd8+ Ke6 70. Re8+ Kd6 71. Rd8+ Ke7 72. Rh8 (72. Rb8 Rxf3 73. Kd5 {is still difficult for White, but her king is better positioned.}) 72... Rxf3 73. Rxh5 Kd6 {now White can do little to stop Black from cleaning up.} 74. Rg5 Rg3 75. Rf5 Re3 76. Rf7 Rxe4+ 77. Kd3 Re3+ 78. Kd2 Rg3 0-1