Annotated Game #132: Flawed Draw

The following second-round game illustrates the value of seeing patterns pop up in analysis of your own results.  In this case, I achieved a significant positional plus out of the opening, but mis-evaluated the relative value of pieces (knight and bishop) which lead to an incorrect exchange on move 20 and eventually exchanging down into an equal ending.  It is exactly this sort of thing that prompted me to post the related Mastery Concept.  There was also a missed endgame opportunity, subtle but well worth keeping in mind for the next similar situation.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class B"] [Result "1/2-1/2"] [ECO "A22"] [Annotator "ChessAdmin/Houdini"] [PlyCount "65"] [EventDate "2012.07.??"] [EventType "swiss"] [EventRounds "9"] {A22: English Opening: 1...e5 2 Nc3 Nf6} 1. c4 e5 2. Nc3 d6 3. Nf3 Nf6 4. g3 Nbd7 5. Bg2 c6 6. O-O Be7 7. d3 O-O 8. Rb1 a5 9. a3 Re8 {Black has pursued an Old Indian-type setup in the opening, which is a little passive - especially in the placement of the dark-square bishop - but solid. White continues with the standard plan of queenside expansion.} 10. b4 axb4 11. axb4 Nf8 12. b5 c5 $146 {this is a significant strategic error, essentially giving up d5 and the long diagonal without a fight.} (12... Qc7 13. Qb3 Bd7 14. Ba3 Ng6 15. d4 Bf8 16. d5 c5 17. e4 Rab8 18. h3 h6 19. Kh2 Nh7 20. Bb2 Be7 21. Ra1 {1/2-1/2 (21) Smagalski,S (2042)-Milanowski,J (2131) Polanica Zdroj 2004}) (12... h6 $11) 13. Bg5 $14 {my idea was to eliminate Black's remaining defender of d5.} h6 14. Bxf6 Bxf6 {Black has the pair of bishops, notes Houdini via the Fritz interface, but the dark-square bishop is "bad" and the light-square one is doing nothing currently.} 15. Nd5 (15. Nd2 {would have been a useful preparatory move here, unleashing the Bg2 and preventing Black from developing the Bc8.}) 15... Be6 16. Nd2 Bg5 17. h4 {I chose the more aggressive move here, which however is inferior to the blocking move e3.} (17. e3 {and now the dark-square bishop is even more limited. The move also prevents a trade of the bad bishop for the Nd2, which has strong potential in this position.}) 17... Be7 $6 {my opponent should have seized the opportunity for the piece exchange.} (17... Bxd2 18. Qxd2 Nd7 19. Ra1 Bxd5 20. Bxd5 $14) 18. Ra1 {the obvious method of continuing on the queenside, but b6 should also be considered.} (18. b6 Bxd5 19. Bxd5 Rb8 20. Ne4 $16) 18... Rxa1 19. Qxa1 Qb8 (19... Bxh4 $5 { the engine considers this diversionary sacrifice slightly preferable. It would certainly generate more activity for Black, whose pieces are largely on the sidelines. One possible continuation:} 20. gxh4 Ng6 21. Ne3 Qxh4 22. Re1 $16) 20. Nxe7+ $6 {this betrays my lack of positional understanding, specifically of the relative value of the minor pieces. White essentially starts to liquidate his own advantage.} (20. b6 $5 Bd8 21. Qa7 $16) (20. Qa2 {would also be a good plan, with the idea of Ra1 to follow.}) 20... Rxe7 $14 21. Qa5 $6 { this was simply dumb, allowing Black a tempo to chase the queen and also giving up the a-file. The plan with Qa2 (or Qa3) would be better.} b6 $11 22. Qc3 Ra7 23. Ra1 Rxa1+ {Black need not have been in a rush to exchange, a typical Class player reaction. Maintaining the tension would have been better for control of the a-file.} (23... f5 $5) 24. Qxa1 {White now has a small positional advantage.} Nh7 $6 {poor placement for the knight.} (24... Bg4 25. Kf1 Ne6 26. Qa8 Qxa8 27. Bxa8 $14) 25. Qa8 {this move heads for an obvious draw, although Black played on for a while after the exchange. I was not sophisticated enough to spot an alternative.} (25. Nb1 $5 {is what the engine finds, getting the knight into play effectively. For example} Nf6 26. Nc3 Kf8 27. Qa6 Bc8 28. Qa8 Qxa8 29. Bxa8 Be6 30. Na4 $16) 25... Qxa8 $11 26. Bxa8 Kf8 27. Nf1 Ke7 28. Ne3 Kd8 29. Bd5 Nf6 30. Bg2 Ke7 31. Kh2 Kd8 32. Bh3 Ke7 33. Bxe6 1/2-1/2