14 April 2013

Annotated Game #90: R+P <> N+B

This fourth-round tournament game offers some interesting lessons and contrasts in how to count the material balance.  I did well out of the opening as Black, then faced a major decision on move 10, whether or not to take the f2-pawn.  Houdini validates the choice made in the game, which focuses instead on not falling too far behind in development.  However, several moves later, Black again targets the f-pawn and does the classic B+N for R+P exchange.  This is a classic material counting error, from the days where a piece was considered to be worth 3 pawns.  In reality, it's better to consider a piece as 3.25 pawns, which makes it clear that the above trade is detrimental.  The bishop pair can also be considered to be worth up to 0.5 pawns as a rule of thumb, making the trade even worse on counting considerations alone.

I wasn't completely ignorant of the above at the time, but also made an error in judgment in this particular game that the rooks would be able to compensate by operating down the central files.  This turned out not to be the case, as by move 22 it's clear that the rooks have nowhere to go and cannot penetrate - until White blunders by snatching a pawn and allowing a rook fork on the second rank.

As a secondary lesson, this game pointed out a consistent thought process error, which was Black's failure to advance the g-pawn (on two different occasions) to attack and trap the White knight.  Black simply failed to even consider the possibility of a g-pawn advance, based on the "general principles" of not making weakening pawn moves in front of the king.  This is another example of where using CCT (Checks, Captures and Threats) would have resulted in finding the correct candidate move (the threat to trap the knight), which was worth far more than the resulting positional weakness.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "Class C"] [Black "ChessAdmin"] [Result "0-1"] [ECO "D10"] [Annotator "ChessAdmin/Fritz/Houdini"] [PlyCount "66"] [EventDate "2007.01.??"] [EventType "swiss"] [EventRounds "7"] {D10: Slav Defence: cxd5 (without early Nf3) and 3 Nc3} 1. d4 d5 2. c4 c6 3. Nc3 {played most often at the Class level in tournaments, from my observations, with the idea of transposing into another main line variation or other opening such as the Semi-Slav. Or perhaps it just seems the most obvious follow-up, instead of the main line Nf3. Black's response is the most testing.} dxc4 4. a4 {if White is going to play the Queen's Gambit, he really should follow through, rather than be so concerned with blocking ...b5 at this early stage. Central play with e4 has proven more effective, with White scoring 57 percent.} e5 ( 4... Bg4 {is an interesting possibility here.}) 5. Nf3 {Black scores around 60 percent from this position.} (5. dxe5 Qxd1+ 6. Kxd1 Na6 {scores very well for black, around 67 percent.}) 5... exd4 6. Qxd4 Qxd4 7. Nxd4 Nf6 (7... Bc5 { is by far the most popular move, although the text move scores about the same (very well, around 67 percent) for Black.} 8. e3 Bxd4 (8... Na6 9. Bxc4 Nb4 10. O-O Nf6 11. Nb3 Bb6 12. a5 Bc7 13. Ra4 Nbd5 14. Nxd5 Nxd5 15. Bxd5 cxd5 16. Bd2 Bd7 17. Rd4 Bb5 18. Rb1 Bc4 19. Nc1 Be5 20. Rh4 Bf6 21. Rf4 Be5 22. Rh4 f6 23. Bc3 {Doric,D (2402)-Dabo Peranic,R (2262)/Bosnjaci CRO 2006/The Week in Chess 583/1/2-1/2 (53)}) 9. exd4 Be6 10. Ne4 Ke7 11. a5 Na6 12. Bd2 Nf6 13. Nxf6 gxf6 14. Rc1 Rhg8 15. g3 Bd5 16. Rg1 Rg4 17. Be3 Nb4 18. Bxc4 Bxc4 19. Rxc4 Nd5 20. Ke2 Kd6 21. Rgc1 Rc8 22. Kf3 {Ortlauf,E-Degering,F/Bayern 2000/EXT 2001/0-1 (39)}) 8. e4 (8. e3 $5 $11) 8... Bc5 {now this move has some bite to it, hitting both the d4 knight and through it the weakened f2 square.} 9. Nf3 Ng4 { taking advantage of the weak f2 pawn.} (9... Be6 {played first might be a more effective approach, getting another piece out and forcing White to pay for recapturing the c4 pawn.} 10. Ng5 Ng4 11. Nxe6 fxe6 12. Bxc4 Nxf2 13. Rf1 Rf8 { and now} 14. Bxe6 $6 (14. Ke2 Nd7 15. Bxe6 Ne5) 14... Nd3+ 15. Ke2 Rxf1 16. Kxf1 Nd7 {gives Black a lead in development and the isolated e-pawn to attack.} ) 10. Bxc4 Nd7 {is in fact preferred by Houdini. Black does not want to fall too far behind in development.} (10... Bxf2+ {is the material grabbing line favored by Fritz.} 11. Ke2 Bb6 12. h3 Nh6 (12... Nf6 13. e5 Nfd7 {and White has good compensation for the pawn with his space advantage and Black's hampered development.}) 13. Bf4 {again, White's lead in development and open lines (such as the d-file) compensate for the pawn.}) 11. Rf1 (11. O-O { seems more logical. Leaving the king in the center with most of the pieces still on, even with the queens gone, will allow Black some possible threats.}) 11... Nde5 12. Nxe5 Nxe5 13. Be2 Ng4 {Black intends to trade on f2, reasoning that in the material swap (gaining R+P for N+B) will be good, as Black's second rook can operate on the central files. This is both bad counting in general terms (normally two pieces are worth more than rook and pawn) and a misjudgment of this particular position.} (13... Ng6 {is Fritz's preference. The knight is no longer hanging and eyes the f4 and h4 squares.}) (13... Be6 { is Houdini's choice, placing the bishop on its best square.}) 14. h3 $14 Bxf2+ $2 {Fritz is horrified! The engine gives White a +- here.} (14... Nf6 {would be OK here.} 15. e5 Nd7 16. f4 Bd4 $11 {White has more space, but his pawn structure is weaker.}) 15. Rxf2 $16 {Houdini is less horrified, but still gives White over a pawn equivalent advantage after the trade.} Nxf2 16. Kxf2 Be6 17. Be3 O-O 18. Bd1 {White's central maneuvering seems a bit slow.} (18. b4 {White can use all his pieces to support action on the queenside. For example} a6 (18... a5 $5 19. b5 cxb5 20. Nxb5) 19. a5 Rad8 20. Na4 {and Black already has problems defending.}) 18... Rfe8 (18... f5 {would seize an opportunity to try and open more lines for the rooks, or if White avoids an exchange, at least break up White's total central control.} 19. e5 Rad8) 19. Bc2 {now the Re8 effectively isn't doing much of use, as the e-pawn can't be attacked again easily.} Bc4 {Black does some slow maneuvering of his own.} 20. b3 Ba6 21. Ne2 (21. Na2 b6 22. Nb4 Bb7 23. a5 c5 24. Nd5 {looks superior.}) 21... Rad8 22. Nf4 Rd7 {Black hopes doubling rooks on a central file will be useful, but the e-pawn is adequate defended and the rooks have nowhere to go on the d-file, unless White blunders.} 23. Bxa7 $4 {White blunders, evidently entranced by the hanging pawn.} (23. Kf3 {with excellent chances for White, notes Fritz.}) 23... Rd2+ $19 {the loose king placement finally comes back to haunt White.} 24. Kf3 Rxc2 {Black is up an exchange and has powerful piece placement, compared with White's weak, uncoordinated pieces. The rest of the game is not difficult, although Black now misses a key tactic that would have shortened it further.} 25. Rb1 {White fails to see (although so does Black) that the Nf4 has no squares left, as e2 is dominated by Black's rook and bishop.} f6 (25... g5 $1 {the failure to find this move was an obvious flaw in my thinking process.} 26. b4 Bc4) 26. g4 Rc3+ 27. Kg2 (27. Be3 g5 28. Nh5 Kf7 29. Ng3 { would have put up more resistance.}) 27... Rxe4 28. Nh5 Re2+ 29. Kg1 Rxh3 30. Bf2 Rf3 31. Bc5 Rc2 (31... g6 {again, Black misses the fact that the knight is out of moves.} 32. b4 Bd3) 32. Bd4 c5 33. Ba1 Rff2 {and White can only postpone mate, due to the fact that the bishop covers the f1 square.} (33... Rff2 34. Nf4 Rxf4 35. Rd1 Rxg4+ 36. Kh1 Rh4+ 37. Kg1 Rhh2 38. Rd8+ Kf7 39. Rd7+ Kg6 40. Rxg7+ Kxg7 41. Bxf6+ Kxf6 42. a5 Rcg2#) 0-1

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