03 May 2014

Commentary: Women's Grand Prix Khanty-Mansiysk 2014 - Round 5

I chose the following game for study because it illustrates well the sometimes amorphous concept of positional compensation for a pawn.  In contrast with her round 1 game, Hou Yifan is unable to immediately recapture her Queen's Gambit pawn, but is not bothered by this fact.  She goes on to play exactly as required in order to actively press Black, keeping her off-balance and unable to consolidate her position; specifically, Black fails to develop her pieces well enough in order to be able to take advantage of the extra pawn.  Eventually Black stumbles under the pressure and White crushes her with rooks on the 7th rank.

It is worth noting that the Houdini engine had Hou either slightly favored or equal while down the pawn for the entire time (until Hou established a clear winning advantage).  Engine evaluations are sometimes rightly criticized for being too materialistic, but I have not found Houdini to have this flaw.

[Event "4th WGP 2014"] [Site "Khanty-Mansiysk RUS"] [Date "2014.04.14"] [Round "5.4"] [White "Hou Yifan"] [Black "Muminova, Nafisa"] [Result "1-0"] [ECO "E04"] [WhiteElo "2618"] [BlackElo "2321"] [Annotator "ChessAdmin/Houdini"] [PlyCount "61"] [EventDate "2014.04.09"] [SourceDate "2014.01.04"] 1. c4 e6 2. g3 d5 3. Nf3 Nf6 4. Bg2 a6 {this is not one of those types of positions where ...a6 will be inevitably played at some point, so throwing it in this early appears artificial. White scores a healthy 60 percent from this position.} 5. d4 {transposing to a Catalan where Black's previous move definitely looks strange. However, the point is that White cannot automatically regain the pawn after the capture on c4, as ...b5 is now possible.} dxc4 6. O-O {it's sometimes hard to remember that the Queen's Gambit is actually a gambit, but now White is playing it as such.} Nc6 7. Nbd2 {not the most promising-looking move. Top players normally play e3 or Bg5.} Nxd4 {although by no means obligatory, this has been played in all 8 database games.} 8. Nxc4 {White has indirectly exchanged the d and c pawns.} Bc5 { Black plays to maintain the central knight, rather than trade it off.} 9. Nfe5 {White in turn also foregoes exchanging the Nd4, preferring to establish her own knight in the center.} O-O 10. Be3 {developing a piece and maintaining pressure in the center, temporarily pinning the knight against the hanging Bc5. Interestingly, Houdini already gives a small plus to White, meaning she has more than enough compensation for the pawn.} Ba7 {protecting the bishop in the best way, although it still looks awkward.} 11. Rc1 $14 {What does White have for the pawn? The Ne5 is excellently placed and cannot be easily driven off. The Nc4 is also strong and can be routed to c6 if Black plays ...b5. White's Bg2 also looks excellent, while its counterpart is doing nothing on c8 and will be a pain to develop. Finally, the half-open c-file is already occupied by a White rook.} c5 {Black attempts to play as actively as possible and supports the d4 outpost.} 12. Bd2 {White judges that the bishop has no future on the g1-a7 diagonal and prepares to reroute it. This also clears the square for the e-pawn to kick the Nd4.} Nd5 {besides centralizing the knight, this blocks the long diagonal and potentially will assist Black in developing the queenside.} 13. e3 Nb5 14. Qe2 {while this develops the queen to a useful square, the main effect is to clear d1 to develop the other rook.} Nd6 { Black looks to start some exchanges, in the hopes of trading away White's advantages.} 15. Rfd1 Nxc4 16. Nxc4 (16. Qxc4 {would give Black easier play.} Qc7 17. Nf3 b5 18. Qh4 f6 $11) 16... b5 17. Ba5 (17. e4 {immediately is also possible.} bxc4 18. exd5 exd5 19. Bc3 {and although now down two pawns, White still has the upper hand.} Be6 20. Bxd5 Bxd5 21. Qe5 f6 22. Qf5 g6 23. Qxd5+ Qxd5 24. Rxd5 $14) 17... Qe7 18. e4 {White must continue to play actively.} ( 18. Ne5 $6 Bb7 {and now Black has a freer game and the material advantage will start playing more of a role.}) 18... Nb4 {a committal move on the queenside. White can now transform Black's pawn structure there to something much less effective, while continuing her central play.} (18... Nf6 $5) 19. Bxb4 cxb4 20. Ne5 (20. e5 Bb7 21. Bxb7 Qxb7 22. Na5 {is Houdini's preferred continuation. White's pawn on e5 is strong and cramps Black, while her rooks look excellent and the knight is prepared to hop into c6.}) 20... Qg5 (20... Bb7 {it seems like finally getting this piece into the game would be a good idea.}) 21. Nc6 e5 {a useful move for Black that would have been prevented by an earlier e5 on White's part.} 22. h4 {White pre-empts potential activity by Black on the kingside and kicks the queen.} Qf6 23. b3 {White decides not to rush with the pawn capture on b4 (and in fact never plays it).} a5 $6 {playing a pawn move here essentially gives White a free tempo and shows too great an attachment to the b4 pawn. The b5 pawn is immune to capture because of the threat to f2, but White can immediately remedy that.} (23... Be6 $11) 24. Rc2 Bb7 $2 {ironically the bishop finally develops, and it's the losing move.} 25. Nxa7 Rxa7 26. Rc7 { the pin against the Ra7 and the fact that the Bb7 is otherwise unprotected mean that White now has too many unanswerable threats.} Qb6 {this attempts to remedy the pin situation, but White can powerfully double rooks on the 7th rank and Black cannot do anything about it.} 27. Rdd7 a4 {Black attempts to distract White with this queenside sortie, but to no avail.} 28. Kh2 {White puts safety first, getting the king out of the f-pawn pin and off the back rank.} h6 29. Qe3 Qa6 30. Qc5 {the queen now enters with decisive threats.} axb3 {again, more desperately, attempting to distract White.} 31. Qxf8+ { and it's mate in 3 (or 1, if Kxf8).} 1-0

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