30 March 2015

Annotated Game #145: Imbalance and attack

The following sixth-round tournament game revolved around the strategic imbalance between Black's queenside pressure and White's central/kingside dominance.  Out of the opening, Black had a small plus and the initiative, but a relatively complicated unforced sequence starting on move 16 led to me winning a pawn and establishing the structural imbalance.  During the game I was worried about Black mobilizing his queenside majority (including an advanced passed c-pawn), but my central pawn roller and kingside attack - helped by an opened h-file - were decisive, developing too quickly for Black to develop any counterplay.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class B"] [Result "1-0"] [ECO "A17"] [Annotator "ChessAdmin/Houdini/Komodo 8"] [PlyCount "65"] [EventDate "2013.01.21"] [EventRounds "7"] {A17: English Opening: 1...Nf6 with ...Bb4 A17: English Opening: 1...Nf6 with . ..Bb4} 1. c4 Nf6 2. Nc3 e6 3. Nf3 {here Black could opt for a Nimzo-Indian structure with ...Bb4, but I felt (correctly) that he would go instead for a QGD one.} d5 4. e3 {thanks to analyzing my own games, my past weakness in QGD structures prompted me to come up with the following solid approach.} Be7 5. b3 c5 6. Bb2 Nc6 7. cxd5 exd5 8. d4 {my opponent appeared surprised by this. He likely thought that if I was going to play d4, I would have done so earlier. Here it is necessary to stop the advance of the Black d-pawn and it exerts control over e5.} b6 $146 {this prevents White from getting a classic IQP structure versus Black after dxc5, but also has its drawbacks, namely leaving the Nc6 unprotected by a pawn.} (8... O-O {is normally played here.} 9. Be2 cxd4 10. Nxd4 Bc5 $11) 9. Bb5 Bb7 10. Ne5 {the engine considers this a bit hasty, preferring to develop with O-O or Rc1.} Qc7 11. Qf3 {at the time, I felt this was a key benefit of being able to get in Ne5. White's queen is well-placed to pressure d5 and has an open field on the kingside.} O-O 12. Nxc6 {my intent here was to exchange off two pairs of minor pieces and then take on c5, followed by pressuring the Black c- and d-pawns as much as possible. However, I did not carry the plan through, due to a lack of confidence. The engine assesses it as the best choice.} (12. Nxd5 $2 {trying to grab the pawn fails to} Nxd5 13. Qxd5 Nxd4 $1) 12... Bxc6 13. O-O (13. Bxc6 Qxc6 14. dxc5 bxc5 $11) 13... Bb7 {Black now avoids the bishop exchange.} 14. Rac1 a6 $15 { by this point Black has a small positional plus and the initiative.} 15. Bd3 c4 {Black mobilizes his queenside pawn majority, but neither he nor I saw the full consequences of this decision immediately.} 16. Ne2 {I had planned this move when retreating the bishop to d3. I was relying on the c-file pin to help me resolve the situation; Black does me a favor and immediately goes wrong.} ( 16. Bb1 $15 {is a simpler way to handle the threat.}) 16... Qd6 $2 {leaving the Bb7 undefended, although there is a partial tactical justification for this.} (16... b5 {is the straightforward way to play, reinforcing c4.} 17. Ng3 Bd6 18. bxc4 bxc4 $15) 17. bxc4 $14 {only afterwards did I see that Black could in fact retake with the d-pawn. The resulting sequence creates a huge strategic imabalance, however, ultimately to White's favor.} (17. Bxc4 { is the simpler and more effective move. For example} dxc4 18. Qxb7 cxb3 19. axb3 Rfb8 20. Qc7 $16) 17... dxc4 {with White's bishop now hanging as well, Black at first appears OK, but I can now gain a clear advantage.} 18. Bxh7+ { this is good for White, although taking on b7 is even better, according to the engine. I felt that the open h-file was even more important than the material.} (18. Qxb7 cxd3 19. Nf4 $16 {and now Black's d-pawn will eventually fall.}) 18... Kxh7 19. Qxb7 {we now have an interesting imbalance with the pawn structure. White dominates in the center and has an extra pawn, but Black's queenside majority has a lot of potential if mobilized and the c-pawn is more advanced. Komodo 8 assesses that Black has partial compensation for the pawn after an immediate ...b5, consolidating the structure.} Rfb8 $6 {this simply drives White's queen to a better square.} (19... b5 20. Ng3 (20. Qf3 Qd5 $14) 20... g6 21. Qf3 $14) 20. Qf3 $16 b5 21. e4 {I felt a strategic imperative to mobilize my central forces and attack both in the center and on the kingside, as the queenside is already effectively lost.} (21. Nf4 $5 {might be a good preparatory move for e4, getting the knight into play.}) 21... Qb4 $2 {Black had to avoid the pawn fork on e5, but this leads to ruin. During the game, of course, this was not immediately clear, but I felt that Black had over-committed to the queenside and that my attack would come first.} (21... Qe6 22. Ng3 Qg4 $16) 22. Bc3 $18 {this appeared to be a bit of a surprise to my opponent, although it seems to be a logical move. Perhaps he saw that he could then win the a-pawn; by this point, however, the material lost is not important. Black's queen gets walled off from the action and White's attack rolls forward.} Qa3 23. e5 {I keep up the forcing play, gaining tempi and not allowing Black breathing room.} Nd7 $2 {a simple blunder that essentially decides the game immediately, although Black's life would have been very difficult in any case. Black's king is far too exposed and Black's pieces are too far away to help defend it.} (23... b4 {praying for a miracle} 24. exf6 Bxf6 25. Nf4 $18 {and now if} bxc3 26. Rxc3 Qe7 27. Nd5) (23... Ng8 24. Qf5+ Kh8 25. Qxf7 $18) 24. Qf5+ {I immediately spotted the queen fork.} Kg8 25. Qxd7 {with the extra material in hand, I no longer had to worry as much about the outcome, although I continued to play carefully.} Rd8 (25... Bg5 {hardly improves anything, notes the engine.} 26. Rc2 Bh6 27. e6 $18) 26. Qg4 Qxa2 { perhaps Black thought I would try to trap the queen after this, but it has an out on d3.} 27. e6 {the biggest threat is now d5 with a mate threat to g7.} Rd5 {this blocks the pawn advance for the moment, but just loses differently.} 28. exf7+ Kf8 29. Nf4 {bringing the knight into the attack with tempo. Now there is no way out for Black, as White has too many ways to break through.} Rd6 30. d5 Bf6 31. Bb4 Kxf7 32. Bxd6 Re8 33. Qg6+ (33. Qg6+ Kg8 34. Qxe8+ Kh7 35. Qg6+ Kh8 36. Rce1 Qxf2+ 37. Rxf2 Be5 38. Bxe5 a5 39. Qxg7#) 1-0

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