The positional maneuvering game turned more violent after White's ambitious pawn break in the center on move 15, which created some potential threats for him (including a possible mate on h7 later on) but also left his position looser, something which became clear after he played 23. f4. I thought during the game that he was being over-optimistic about his attacking chances and leaving behind vulnerabilities. Despite this, the game was dynamically equal until I (under major time pressure) played 27...Be1. The one correct continuation for White after 28. Re3 would lead to an endgame with technically balanced material (two bishops vs. rook and pawn) but that would favor White's chances. However, my opponent failed to see the subsequent bishop check on f2, then the necessary (and not obvious) tactic to follow, so I ended up the exchange and a pawn, sufficient to win the endgame after forcing some exchanges.
Aside from the time pressure lurch on move 27, I feel I played a solid game and adhered well to my thinking process requirements, so it was a positive experience overall. In practical terms, without my 27th move and its creation of threats, I may well have only ended up with a draw, so this is another example of the quirks of chess performance in practice.
[Event "Slow Swiss #9"]
[Site "Chess.com"]
[Date "2013.10.17"]
[Round "?"]
[White "Yamaduta"]
[Black "ChessAdmin_01"]
[Result "0-1"]
[ECO "A12"]
[WhiteElo "1507"]
[BlackElo "1483"]
[Annotator "ChessAdmin/Houdini"]
[PlyCount "94"]
[EventDate "2013.??.??"]
[TimeControl "45"]
1. Nf3 Nf6 {a noncommittal response, as the only thing it really rules out is
the Dutch Defense.} 2. b3 {the Nimzo-Larsen Attack. The idea is to undermine
and attack Black's center, whether one is established with e5/d6 or more
ambitiously pursued with d5/c5. I chose instead to follow a line where White
is not given an obvious plan.} d5 3. Bb2 c6 {entering a Slav-type setup.
Unambitious, but it leaves White few obvious targets to work against.} 4. d3
Bg4 {after White's previous move, this is the only good square for the bishop.}
5. Nbd2 Nbd7 6. g3 e6 7. Bg2 Be7 8. O-O O-O {Black now has standard Slav setup,
except with the bishop on g4 rather than f5. It provides a small space
advantage and will also be difficult for White to challenge.} 9. c4 Rc8 {
developing the rook to a useful square, also making the pawn exchange on d5
not terribly attractive for White.} 10. a4 {now out of the database; the text
move was evidently aimed at restraining a potential ... b5 advance, which I
was in fact considering. h3 or a3 are the two favored moves in this position,
based on a small game sample.} a5 {seizing control of b4, now that the a-pawn
can no longer cover it.} 11. Re1 Bxf3 {the light-squared bishop has little
prospect and is therefore exchanged for one of White's good knights, also
allowing Black's next move to have more bite.} (11... Bb4 {immediately also
looks good, with somewhat different play, being Houdini's choice.}) 12. Nxf3
Bb4 {I debated earlier whether to try to occupy b4 with the bishop or a knight.
The knight would have taken longer to deploy and the bishop usefully covers e1
from here, keeping the rook off the key e-file.} 13. Rf1 Qe7 {connecting the
rooks, preventing a possible Ba3 to exchange off the Bb4, and adding the
queen's weight to the e-file.} 14. Qc2 {supporting the e4 push and also
allowing White to seize the b1-h7 diagonal, once it opens.} Rfe8 {with the
idea of potentially supporting a push of Black's e-pawn. This however has the
drawback of taking away a retreat square from the Nf6.} 15. e4 {with this
rather ambitious pawn break, White injects some activity into his position and
starts creating some threats. Black has to be careful about a possible mate
threat on h7 later on, for example.} dxe4 {I thought the opening of the d-file
would benefit Black.} 16. dxe4 {now the e5 push becomes a threat and should
have been stopped immediately.} Rcd8 {I calculated that White could not get
anything from an attack, but prophylaxis against the e5 advance was still
better.} (16... e5) 17. Ng5 $6 (17. e5 Ng4 {I considered this to be OK for
Black.} 18. h3 Nh6 {and the knight placement is awkward, but it cannot be
trapped and has a nice square on f5 waiting for it.}) 17... e5 {I don't pass
up the chance again to block the advance, which is now more critical with the
knight on g5. The pawn on e5 requires protection, which is a little awkward,
but at the same time it keeps the Bb2 out of the game.} 18. Rad1 Nf8 {thinking
defensively, focused on the e5 pawn and the Ng5.} (18... Nc5 $5) 19. Bc1 {
evidently seeking to redeploy the bishop to a more useful diagonal. However,
this takes the pressure off e5 and allows Black's pieces more freedom.} Ne6 {
I thought for a long time over this, with alternatives including ...Ng6.
Ideally with the text move the knight would go to a strong outpost on d4, but
White stops that by exchanging.} 20. Nxe6 Qxe6 21. Bd2 c5 {an alternative was
retreating with ...Qe7, to maintain piece control of b4, which is Houdini's
second choice. I still had thoughts of shifting the other knight to d4, the
main reason behind the text move.} (21... Bxd2 22. Rxd2 c5 {is Houdini's
preference, showing how the strongpoint on d4 can be properly exploited with ..
.Rd4. For example} 23. Rfd1 Rd4 {and White cannot exchange without creating a
strong central passed pawn for Black, who otherwise can build up on the d-file.
}) 22. h3 {taking away the g4 square from the Nf6.} h6 {preventing Bg5. I was
content to see what White would try next.} 23. f4 {this was something of a
surprise to me, as it loosens White's position considerably and will expose
the e-pawn to attack. It also indicated to me that White wanted to play for a
win.} exf4 {otherwise f5 will be strong for White. Houdini agrees with the
exchange, but assesses that the Bd2 should be exchanged off first; this makes
sense, taking away the two bishops and not allowing the bishop to move to a
better square on f4.} 24. Bxf4 Rxd1 {it is necessary to exchange on the d-file
prior to capturing on e4 with the knight.} (24... Nxe4 $2 25. Rxd8 Rxd8 26.
Bxe4) 25. Rxd1 Nxe4 {Houdini considers this the best sequence, but still rates
it as equal, with White having compensation for the pawn. White must bring his
pieces into play actively in order to obtain it, however.} 26. h4 $6 {allowing
the Bg2 to move without leaving the h-pawn hanging. However, the pawn advance
leaves additional holes.} (26. Rd5 $5) 26... b6 {similarly moving the b-pawn
out of the way of the Bg2.} (26... Nc3 {looks interesting.}) 27. Rd3 Be1 $6 {
I was down to about 2 minutes on the clock here and decided to go for the more
active option that could pose more problems for my opponent, although it was
unclear.} (27... Nf6 {I considered briefly and it seems easiest to play in
objective terms, simply retreating out of danger.}) (27... f5 {was also a
possibility that I considered, eventually deciding that I did not want to
continue the struggle over the Ne4. Houdini considers it to be fine, however.})
28. Re3 {my opponent mentioned that he missed the bishop fork; it is easier to
miss seeing backwards movements for pieces. The surprise no doubt caused him
to miss the best continuation.} Bf2+ 29. Kh2 $2 (29. Qxf2 Nxf2 30. Rxe6 Rxe6
31. Kxf2 {I think should be a draw in the endgame, although Houdini shows over
a pawn equivalent plus for White. The two bishops could prove to be the
winning edge, another argument for why Black should have exchanged the Bd2 off
earlier.}) 29... Bxe3 30. Bxe3 Nf6 {finally the knight retreats safely. Black
has a won game, being up the exchange and a pawn. The strategy at this point
is to create threats against White's king. Even if White successfully defends,
Black will have the opportunity to exchange off material and head into a won
endgame.} 31. Bf4 Ng4+ 32. Kg1 Qe1+ 33. Bf1 Ne3 34. Qf2 Qxf1+ {Black forces
the exchanges into the endgame.} 35. Qxf1 Nxf1 36. Kxf1 f6 {Black's bishop is
increasingly constrained and the one point it can attack (b6) can be easily
held by the rook on the 6th rank while Black's king is activated.} 37. Kf2 g5
38. Bc7 Re6 39. Kf3 Kf7 40. h5 f5 41. Bd8 {now the bishop is inevitably
trapped.} Ke8 42. Bc7 Kd7 43. Bb8 Kc8 44. Ba7 Kb7 45. Bxb6 Kxb6 46. g4 fxg4+
47. Kxg4 Rf6 0-1