Annotated Game #41: Stymied in an English-KID

This next tournament game is illustrative of how certain apparently subtle decisions can turn a potentially winning positional advantage into a draw.  My opponent transposes into a King's Indian Defense (KID) setup against the English, but from moves 8-11 succeeds neither in disrupting White's plans for queenside expansion, nor in establishing any kingside counterplay of his own, giving White an advantage.

White's move 12 indicates that he is looking to open up the a-file with pawn play, rather than fix Black's weaknesses and exploit them with his knight.  With some help from Black, White executes an advantageous piece trade (knight for bishop) on e6, but then errs by also trading his dark-square bishop for Black's. After seizing the a-file with the help of his monster Bg2, White is unable to exploit it after Black redeploys his forces to prevent further penetrations.

I've previously run across this problem in the English, where I'm able to achieve a large queenside space advantage, but then lack the wherewithal to make any further progress.  The improvements and other potential avenues of play found in analysis (particularly on moves 12 and 19) should help me overcome this problem in the future.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class B"] [Result "1/2-1/2"] [ECO "A26"] [Annotator "ChessAdmin/Fritz/Houdini"] [PlyCount "49"] [EventDate "2003.??.??"] [TimeControl "240+2"] {A26: English Opening vs King's Indian with ...Nc6 and d3} 1. c4 Nf6 2. Nc3 g6 3. g3 Bg7 4. Bg2 O-O 5. Nf3 d6 {Black elects to go to a KID setup. Another option would be to transpose to a Symmetrical English with ...c5} 6. O-O e5 7. d3 Nc6 8. Rb1 Nh5 (8... a5 {restraining White's b4 is the most popular and effective move here, according to the database.}) 9. b4 Ne7 (9... f5 {is the logical follow-up to Black's previous move and is by far the most played here.} ) 10. Qb3 {now ...f5 would expose Black's king on the a2-g8 diagonal.} c6 { preparing to fight for d5.} 11. a4 {this prepares the b5 push and allows development of Ba3 without getting in the way of the a-pawn.} (11. b5 { immediately is the other main option, which would result in a different queenside pawn structure.}) 11... a6 {this does not prevent White from further advancing his queenside pawns and also leaves a hole on b6. Black at this point needed to get more pieces in play rather than make additional pawn moves. } 12. b5 (12. a5 $5 $14 {would allow White to take better advantage of Black's pawn structure deficiencies and the hole on b6, also freeing a4 for the knight. }) 12... axb5 13. axb5 Be6 (13... h6 {would prevent a future Ng5, allowing Black to develop Be6 without it being challenged.}) 14. Ba3 (14. Ng5 {is preferred by the engines in order to force the bishop off of its valuable diagonal.}) 14... c5 (14... h6) 15. Ng5 {White finally takes advantage of the undefended g5 square, along with a discovered attack on b7 by the Bg2.} Rb8 ( 15... Bc8 {is the best defense, preserving the bishop for future use.}) 16. Bc1 {played in case of ...Bh6 by Black. However, taking immediately on e6 was better.} b6 {again passing up the chance to retreat the bishop.} 17. Nxe6 fxe6 $16 {now the Bg2 is an unchallenged monster and White has excellent prospects on the a-file.} 18. Bg5 Bf6 (18... h6 {immediately challenging the bishop was better, as after} 19. Bd2 {White appears to have gained little, although Black's kingside is slightly weakened as a result.}) 19. Bxf6 {this gives up part of White's positional advantage.} (19. Bd2 {retreating the bishop was best, as White retains much more scope for his dark-square bishop than does Black. Also, Black's Bf6 blocks the activity of the Rf8 and takes away a retreat square from the Nh5.} Bg7 $16) 19... Rxf6 (19... Nxf6 {gets the knight back into the game and doesn't leave the rook on an awkward square. Evidently with the text move, Black had thought he might try doubling heavy pieces on the f-file at some point.}) 20. Ra1 {time to seize the open file, with Black unable to challenge on a8 thanks to the Bg2.} Ng7 (20... Rf7 21. Ra7 $16) 21. Ra6 {while this isn't bad, compare with} (21. Ra7 Nc8 22. Ra2 Ne7 {preventing the Bc6 penetration} 23. Rfa1) 21... Ne8 22. Rfa1 Nc7 23. Ra7 Nc8 24. R7a2 Ne7 25. Ra7 {unable to find a way to make progress, White takes the draw.} (25. Ne4 $5 {is what the engines prefer.} Rf7 26. Qb2 $16 Nf5 27. e3 {is one possible continuation and White has a strong positional plus, but it's still not clear how he can break through Black's defenses.}) 1/2-1/2