Annotated Game #123: Off to a good start

After my "best game ever" to end the previous tournament, the next tournament got off to a good start in the first round with the following game.  I played solidly as Black and was in control of my own destiny the whole time.  The only error was in missing an interesting and hard-to-find knight sacrifice (19...Nxg2!) which serves as a lesson to investigate these sorts of opportunities in more depth, rather than dismissing them because there is no chance for a mate.  As part of my careful play, I also kept in mind the "evil e-file" tactics, showing that learning actually has taken place as a result of my study program (always a positive).

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "Class B"] [Black "ChessAdmin"] [Result "1/2-1/2"] [ECO "D40"] [Annotator "ChessAdmin/Houdini"] [PlyCount "53"] {D40: Queen's Gambit Declined: Semi-Tarrasch with e3} 1. c4 c6 2. e4 d5 3. exd5 cxd5 4. d4 {my opponent admitted to not knowing the Panov-Botvinnik Attack, but played this as the closest thing to a queen pawn-type opening.} Nf6 5. Nc3 e6 {the solid choice, which leads the game into territory that the opening books classify as a Semi-Tarrasch queen's pawn defense.} 6. Bg5 Be7 7. Nf3 O-O 8. Bd3 dxc4 9. Bxc4 Nc6 10. O-O a6 {the other main option is b6; in both cases, the idea is to develop with Bb7. With the White bishop on c4, a6-b5 is not in fact a slower route to development, since the Bc4 will have to move.} 11. a3 b5 12. Ba2 {this is in fact the 3-to-1 favorite in the database, versus retreating to d3. With Black about to play Bb7, the Ba2 has the possibility of being involved in a sacrificial tactic at some point on e6, as well as fighting for the d5 square. It can also go to b1 at some point to form a Q+B battery on the b1-h7 diagonal, a common theme that my opponent decides to immediately execute.} Bb7 13. Bb1 (13. Qd3 {is the preferred move here, for example:} Na5 14. Rad1 Bxf3 15. Qxf3 Nc4 16. Bxc4 bxc4 17. Rfe1 Nd5 18. Bxe7 Nxe7 19. d5 Nxd5 20. Nxd5 exd5 21. Rxd5 Qb6 22. Qc3 Rab8 23. Rd2 Rfc8 24. h3 h6 25. Re4 Qb3 26. Qe5 c3 27. bxc3 Qxc3 {Palatnik,S (2480)-Sveshnikov,E (2510) Leningrad 1976 1-0 (31)}) 13... Rc8 {the rook was doing no good on a8 and the c-file is one of Black's few sources of active counterplay.} 14. Qd3 g6 { forced.} 15. Re1 $146 {now out of the database. White eyes the semi-open e-file, thematic in the Caro-Kann, but here Black's defenses are more than adequate.} (15. Rd1 {is what has been played in a handful of games in the database.}) 15... Re8 $11 {having been burned previously due to "evil" e-file tactics, I reinforce my already-strong defenses. This also sidesteps a future Bh6 from White.} 16. Ba2 {with no prospects left on its previous diagonal, the bishop switches back.} Nh5 {following the standard plan of looking to trade minor pieces when the opponent has an isolated queen's pawn.} 17. Bxe7 { Houdini considers that avoiding the exchange is better for White, in accordance with IQP theory.} Nxe7 18. Rad1 $2 (18. g3 $5 $11 {should not be overlooked, notes Houdini via the Fritz interface.}) 18... Nf4 $17 {the point of Black's choice of square for the knight on move 16. However, I failed to see the follow-up sacrificial tactic that could have made it a winning move.} 19. Qe3 $2 (19. Qd2 {is what the engine shows as the best defense.} Bxf3 20. gxf3 Ned5 $17) 19... Nfd5 $2 $11 {what a pity, victory was in sight, comments Houdini. The second best move, in other words.} (19... Nxg2 $1 20. Kxg2 Nf5 { the king is not directly threatened, which is what one would normally look for with a sacrifice on g2, but the Nf3 is now pinned and can't be protected except by the queen, which allows Black to press for the win.} 21. Qf4 (21. Qd3 Nh4+) 21... g5 22. Qc1 Nh4+ 23. Kf1 Nxf3 $19 {and now Houdini judges Black's material and positional advantage to be worth roughly a piece.}) 20. Nxd5 { now a series of exchanges occur which favors Black somewhat.} Bxd5 21. Bb1 Bxf3 22. Qxf3 Nd5 (22... Qb6 {would put more pressure on White. For example} 23. Rd2 Red8 24. Red1 Rc4 25. Qf6 Nd5 $15) 23. Be4 {White moves to equalize the pawn structure and eliminate any Black hopes of a win.} Qd7 24. Bxd5 Qxd5 25. Qxd5 exd5 26. Rxe8+ Rxe8 27. Kf1 {and my opponent offered a draw.} 1/2-1/2