11 May 2013

Commentary - 2013 U.S. Championships, Round 7

In round 7, I found two games to be of particular interest for study purposes.  In the first, Irina Krush resumes her winning ways, this time in a war of maneuver with Viktorija Ni in a Nimzo-English.  Irina does not have an easy way to the win, however, missing an interesting tactic on move 29 and allowing Black for a while to have a small advantage.  In the second, I give props to Yaacov Norowitz for bringing out the aggressive, unbalanced Bronstein-Larsen variation of the Caro-Kann again after losing to Larry Christiansen in round 1.  Facing Sam Shankland, Norowitz varies from his previous effort on move 8 with an improvement, but after exchanging bishop for knight on f3, Black's initiative peters out on the kingside.  In this variation of the Caro-Kann, if Black has no counterplay on the kingside, White normally enjoys the advantage of a free attacking hand on the queenside, which is exactly what happens here.

At the time of posting, live coverage of round 8 (the penultimate one) is underway.  The leader on the women's side, Krush playing Black in a Taimanov Sicilian, looks like she has a significant advantage over Tatev Abrahamyan.  Meanwhile, open championship leader Gata Kamsky is having some difficulty as White against Timur Gareev.

[Event "2013 U.S. and Womens' Championship"] [Site "Saint Louis, Missouri, USA"] [Date "2013.05.10"] [Round "7.4"] [White "Krush, Irina"] [Black "Ni, Viktorija"] [Result "1-0"] [ECO "A17"] [WhiteElo "2470"] [BlackElo "2262"] [Annotator "ChessAdmin/Houdini"] [PlyCount "81"] [EventDate "2013.??.??"] [TimeControl "6000+950"] [WhiteClock "0:27:53"] [BlackClock "0:30:35"] 1. Nf3 Nf6 2. c4 e6 3. Nc3 {instead of playing d4 and heading for a standard queen pawn opening, White switches to an English continuation.} Bb4 {the Nimzo-English.} 4. Qc2 {unlike the Nimzo-Indian, where the text move is merely one option among several major lines, White overwhelmingly chooses Qc2 (and sometimes Qb3) in the English, to preserve his pawn structure after Bxc3; g3 is the one popular alternative to this approach.} O-O 5. a3 Bxc3 {otherwise the bishop move has simply been a loss of time.} 6. Qxc3 b6 7. e3 Bb7 8. b3 { White has a choice in this line between playing b3 or b4; one or the other will be necessary to develop with Bb2. The text move is the more solid way to play, with b4 grabbing a little more space.} d6 9. Bb2 Nbd7 10. Be2 Nc5 { one of the differences between this line and the b4 line is that Black has c5 available for the knight, even if only temporarily.} 11. d4 Nce4 {the e4 square is normally key in the Nimzo and Black takes advantage of her dominance of it.} 12. Qc2 c5 {challenging White's pawn center.} 13. O-O {White wisely chooses to remove her king before initiating action in the center.} Rc8 { the opening phase is over and both sides need to come up with their middlegame plans here.} 14. Rad1 {White's choice of which rook to move indicates that she is more interested in central and kingside play than in the queenside.} Qe7 15. dxc5 Rxc5 {this is a somewhat unusual choice for recapturing, but Black apparently wanted to avoid the below variation. The rook move perhaps would be better justified if Black could swing her rook over to the kingside.} (15... Nxc5 {and now} 16. Bxf6 gxf6 (16... Qxf6 17. Rxd6) 17. Nd2 f5 {is evaluated as equal by Houdini. Human players would of course dislike to see their pawn structure compromised, but in this case it doesn't seem like White can successfully exploit the holes on the kingside.}) 16. b4 (16. Nd2 {is Houdini's preference, with the aim of getting rid of the Ne4.}) 16... Rcc8 17. Qb3 {with tactical threats nonexistent, the middlegame enters a maneuvering phase. This is similar to what normally occurs in the Hedgehog and the position shares some characteristics of that.} Rfd8 18. Bd4 {this move seems largely designed to provoke Black's response.} e5 19. Bb2 {the d6/e5 pawn formation is now weaker and less flexible than the d6/e6 pawn center, especially with the backwards d6 pawn on the half-open file. It is currently well-guarded, but in the long run that could be a weakness. The e5 advance more importantly for the shorter term also creates a hole on d5 which White, if she can, will try to exploit.} Qe6 {Black recognizes the weakness of d5 and moves to reassert control over it, also putting the queen in an excellent central location on the a2-g8 and h3-c8 diagonals.} 20. Rc1 b5 {attempting to force the issue of the fate of the queenside pawns, taking advantage of the pin against the Qb3.} 21. Qd3 {the only good response.} bxc4 22. Rxc4 Bd5 { further exchanges on c4 are not in Black's interest, as her structural weakness at d6 would become much more evident with fewer pieces on the board.} 23. Rcc1 (23. Rxc8 Rxc8 24. Rc1 Rxc1+ 25. Bxc1 {would be an alternate way to play, but without the rooks on the board White does not have a good way to take advantage of the open c-file or increase pressure down the d-file.}) 23... Rb8 24. Qa6 {While the position is still equal, White starts to pick up a slight initiative by making threats Black needs to respond to. The 2-to-1 majority on the queenside and the open c-file are things White can use to try for an eventual advantage, as well as the half-open d-file.} Rb7 25. h3 { apparently intended to prevent ...Ng4 before moving the rook, but Houdini points out a tactical way for White to refute that.} (25. Rfd1 Ng4 26. Rxd5 { not an obvious move} Qxd5 27. Bc4 {and rather surprisingly the queen has no squares.}) 25... Qe7 {Black starts to face difficulties in an increasingly complex and tactical position. Here she retreats her queen to a much less active square.} (25... Rdb8 {is Houdini's suggestion as an alternate method of overprotecting the Rb7, necessary to allow the Bd5 mobility.}) 26. Rfd1 { it's worth observing how White's rooks and other pieces are working together and are well-placed to apply further pressure, while Black's more scattered and less cohesive pieces that are more oriented towards defense.} Bb3 {Houdini flags this as Black's first major error, given the tactic available on move 29. } (26... Rbd7) 27. Rd3 Rb6 28. Qa5 Be6 29. Nd2 (29. Bxe5 {is the tactic Houdini finds, based on a discovered back-rank mate threat.} dxe5 $2 30. Qxa7 { and White is going to pick up one of Black's rooks, for example} Nd7 31. Rxd7 Bxd7 32. Qxb6 $18) 29... h6 {Black now avoids future back-rank problems.} 30. Nf1 (30. Bf3 {would be an immediate way to fight for the e4 square.}) 30... Ne8 31. f3 Nc5 32. bxc5 (32. Rxc5 {is the capture preferred by Houdini, made possible by a pin tactic against the Rb6.} dxc5 33. Rxd8 Qxd8 34. bxc5 Rb8 35. Qxd8 Rxd8) 32... Rxb2 33. Nd2 {now White's pieces are looking rather uncoordinated, especially by comparison to the position on move 26. Houdini awards Black a slight plus here. Black has the open b-file and White's c5 pawn is isolated and weak.} Rdb8 $6 {this lets White off the hook in the center and drops the e5 pawn for insufficient compensation.} (33... Rc8 $15 {seems good for Black, immediately targeting the c-pawn, which is pinned to the hanging Rc1.}) 34. cxd6 Nxd6 35. Qxe5 R8b6 36. Bf1 {White extricates her bishop from the pin on the second rank.} R2b5 37. Qc3 {White has improved her piece placement by reorganizing over the last few moves and Black has no obvious counterplay.} Qg5 {this allows White to complete her consolidation and achieve a winnin position.} (37... Rb2) 38. Rxd6 Rxd6 39. Ne4 Qd5 $2 {this just drops a rook.} (39... Rb3 $16) 40. Bxb5 Rb6 41. Bc4 1-0

[Event "2013 U.S. and Womens' Championship"] [Site "Saint Louis, Missouri, USA"] [Date "2013.05.10"] [Round "7.8"] [White "Shankland, Sam"] [Black "Norowitz, Yaacov"] [Result "1-0"] [ECO "B16"] [WhiteElo "2612"] [BlackElo "2451"] [Annotator "ChessAdmin/Houdini"] [PlyCount "83"] [EventDate "2013.??.??"] [TimeControl "6000+1390"] [WhiteClock "0:35:56"] [BlackClock "0:29:54"] 1. e4 c6 2. d4 d5 3. Nd2 {this move is of course interchangeable with the more usual Nc3 given Black's response here. The only independent significance it has is if Black likes to play the offbeat 3...g6 in the main line Caro Kann, in which case White then has the pawn push c3 in response.} dxe4 4. Nxe4 Nf6 5. Nxf6+ gxf6 {venturing the Bronstein-Larsen variation again, as in round 1.} 6. Nf3 Bg4 7. Be2 e6 8. O-O Rg8 {Black still insists on avoiding the main choice . ..Bd6, but declines to repeat the choice he made in round 1 of ...Qc7. The text move has the advantage of being more immediately aggressive.} 9. Bf4 Bd6 10. Bg3 {this is Houdini's preference and a novelty, based on my database.} Bxf3 {this seems a little premature. White's bishop on f3 is also a very useful addition to his kingside defenders.} (10... Bxg3 11. hxg3 Nd7 $11) 11. Bxf3 $14 {Houdini awards White a slight plus here. White has no significant structural problems and is ahead in development.} f5 12. Qd2 Bxg3 13. hxg3 { this would be a weakening move if Black could take advantage of an attack down the h-file, but this doesn't materialize.} Nd7 14. Rfe1 Qc7 15. d5 {White decides to immediately attempt to seize the initiative, although a preparatory move might have been in order.} (15. c4) (15. Rad1) 15... cxd5 16. Qxd5 O-O-O 17. Qb3 Kb8 {Black has staved off White's immediate threats, but White will now have a much easier time attacking Black's king than vice versa.} 18. a4 Nc5 (18... Qb6 $5) 19. Qe3 {White does well to move his queen away from potential threats to exchange it, placing it on a square that influences the attack on the king via the g1-a7 diagonal while also eyeing Black's weak kingside.} Rc8 20. a5 $16 {this takes away the b6 square from black, cramping his defense. Black is under major pressure and has no counterplay.} Rgd8 21. Ra3 (21. b4 $5) 21... a6 22. Rc3 {the game is now increasingly tactical due to White's bringing more pieces into the attack.} Qe7 (22... Qxa5 {does not work because of} 23. Qf4+ Ka7 (23... Qc7 24. Rxc5 Qxf4 25. Rxc8+ Rxc8 26. gxf4) 24. b4) 23. Qf4+ Qd6 24. Re5 {White brings his other rook into the attack.} Ne4 {forced.} ( 24... Ka7 25. Rexc5 Qxf4 (25... Rxc5 26. Qxd6) 26. gxf4 Rxc5 27. Rxc5) 25. Rd3 Qc7 26. Bxe4 fxe4 27. Rxe4 Rxd3 28. cxd3 Qxf4 29. Rxf4 {White has cashed in his attack for an extra pawn, but the win is not clear in the ensuing rook endgame.} f5 30. f3 Rd8 31. Rh4 Rxd3 32. Rxh7 Rb3 33. g4 fxg4 34. fxg4 Ka7 { Houdini flags this as the losing move.} (34... Rb5) 35. Rh3 (35. g5 Rg3 36. Rg7 Rg4 37. Kf2 {and White will be able to chase the Black rook away.}) 35... Rxb2 36. g5 Rc2 37. g6 Rc8 38. Rf3 Rg8 39. Rf6 Kb8 40. Rxe6 Kc7 41. Kf2 Rf8+ 42. Kg3 {the king can now march up the board and will eventually force the Black rook away.} 1-0

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