Annotated Game #339: How about that a-file

This final-round tournament game followed a common trajectory in the Colle, as I managed to seize on an inaccuracy in an otherwise equal position to put a lot of pressure on Black. I completely miss a Nxf7 sac possibility, pointed out by the engine, but establish a second-best winning positional advantage. Unfortunately I misplay things on the open a-file, giving Black perhaps even a small advantage. After that, a somewhat over-optimistic last shot at active play peters out into a legitimate draw. I was nonetheless pleased with the overall level of play and the result against a higher-rated player, capping a positive tournament result for the first time in a while.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class B"] [Result "1/2-1/2"] [Annotator "ChessAdmin/Dragon 3.2"] [ECO "D05"] [WhiteFideId "-1"] [BlackFideId "-1"] [PlyCount "69"] [GameId "2268222679466048"] {[%evp 0,69,10,38,17,23,32,5,14,9,8,0,9,7,16,4,21,26,10,11,18,7,13,-1,-18,0,17,46,51,23,54,-16,3,117,42,186,41,5,172,124,195,84,153,25,86,182,212,196,12,78,71,7,-88,0,9,-63,-73,-70,4,-27,-30,-82,-64,87,-1,-28,54,-1,1,-26,-1,-51]} 1. d4 Nf6 2. Nf3 c5 3. e3 {a safe choice.} (3. d5 {is the more principled reply, taking advantage of Black's pawn advance, and scores much better in the database than any other move.}) 3... e6 4. Bd3 d5 {now we are back in the main line Colle, via transposition.} 5. b3 Nbd7 6. Bb2 a6 {this seems like one pawn move too many, as development is not advanced enough for Black.} 7. a4 $14 {prophylaxis, aimed at contesting any b-pawn advance.} g6 {this is inconsistent with the earlier e7-e6 advance, since the bishop does not need an extra tempo to develop. That said, if Black is more comfortable playing the position with a fianchettoed bishop, then it is not necessarily a bad choice.} 8. Nbd2 Bg7 9. O-O b6 {The light-square bishop needs to be developed somehow.} 10. Ne5 {not the only good choice of strategy here.} (10. a5 {looks to disrupt Black's queenside. Accepting the pawn leads to trouble after} bxa5 11. Ra2 {followed by Qa1 with pressure against Black's fractured structure.}) (10. e4 $5 {would be the classic Colle pawn lever}) 10... Qc7 11. f4 {now we have the classic Stonewall/Colle attack structure.} O-O 12. c3 {this commits fully to a Stonewall structure, which is safer but less dynamic. Developing the queen would be more flexible.} (12. Qe2) (12. Qe1) 12... Rb8 {removing a defender of the a6 pawn, making it easy to choose my next move.} 13. Qe2 {creating the Q+B battery and connecting the rooks.} Qb7 {it's common to try and justify one's previous less-than-optimal move, which my opponent does here by misplacing her queen to protect the a-pawn.} (13... Ra8 {simply returning the rook to its original square is a bit galling, but best.}) 14. Ndf3 {I thought for a while here. This is not bad, but does not press White's small advantage.} (14. g4 {would start up the standard Stonewall attack on the kingside, targeting the Nf6. I rejected it at the time, thinking it would be too stereotypical.}) (14. Ba3 $5 {would get the bishop off the b-file, where it could be a target, and on to a much more useful diagonal.}) 14... b5 15. Rfb1 {protecting the Bb2 again and opposing the rook to Black's queen.} c4 {Black now seizes some space while keeping the queenside structure intact, thereby equalizing.} 16. bxc4 dxc4 17. Bc2 $11 Nd5 {this was unexpected, for whatever reason, but both looks good and is good.} 18. Qd2 {overprotecting c3.} Qc7 $2 {a good idea to place the queen here, but executed prematurely.} (18... Nxe5 19. Nxe5 f6 20. Nf3 Qc7 $11 {here the e3-e4 pawn lever is not available, as the f4 pawn would hang.}) 19. e4 $1 {this was easy to find, since it seizes space with tempo.} N5f6 20. Ba3 $18 {I felt this resulted in a decisive advantage, which the engine verifies.} Rd8 21. axb5 (21. Nxf7 $1 {is even better, but this sacrifice was not even on my radar.} Kxf7 22. Ng5+ Kg8 23. Nxe6 Qb6 24. Nxd8 Qxd8 25. e5 $18) 21... axb5 22. Bb4 {positionally Black is lost on the queenside, without control of the a-file and with the backwards b-pawn a liability.} Qb7 23. Qe1 {a "small" move, but best. The idea is to redeploy the queen to the kingside and combine with the knight to attack.} Nxe5 24. Nxe5 $6 {this gives away most of the advantage, as I divert my knight from the best attacking square (g5) while also leaving Black's defending knight in place on f6. The Ne5's centralization looks good, but is not useful enough to compensate.} (24. fxe5 $18) 24... Bd7 $14 25. Nxd7 $6 {now we are back to equality. The knight was still superior to the bishop.} Qxd7 $11 26. Ra2 Ra8 27. Rba1 $6 {natural-looking but mistaken, as Black's potential activity on the a-file now outweighs White's.} (27. Rab2 $5 {doubling the potential pressure on the b-file, while not allowing Black to threaten to enter into my position on the a-file.}) 27... Rxa2 28. Rxa2 Nh5 (28... Bf8 {played immediately would activate the bishop to better effect.}) 29. Bc5 {played after a long think, and a little over-optimistic. My opponent in response thought for a while, then did not go for the critical line accepting the pawn sac.} (29. g3 {would be the simplest way to consolidate and maintain equality.}) 29... Bf8 (29... Nxf4 30. g3 Nd3 31. Bxd3 cxd3 32. Qe3 $11) 30. Ra7 $6 {the point of the previous move in my thinking. However, after the essentially forced bishop exchange, it has less of a point.} (30. Bxf8 $11) 30... Qe8 31. Bxf8 Kxf8 32. g3 {unfortunately none of the attacking moves (Qh4 etc.) do anything for White, so I end up consolidating the equal position.} Ra8 33. Qa1 Rxa7 34. Qxa7 Nf6 35. Qc5+ {we were both relatively low on time and recognized that the position was equal, with no progress likely, so a draw was agreed.} 1/2-1/2