A sharp King Indian Four Pawns

[Event "Open invite"]
[Site "http://www.playtheimmortalgame.com"]
[Date "2014.06.25"]
[EndDate "2014.06.26"]
[Round "?"]
[White "Ragwort"]
[Black "BigDoggProblem"]
[WhiteRating "1850"]
[BlackRating "1794"]
[WhiteElo "1850"]
[BlackElo "1794"]
[Result "1-0"]
[GameId "10691192"]

1. d4 Ng8f6 2. c4 g6 3. Nb1c3 Bf8g7 {This is the starting position of the King's Indian Defence. A number of years ago I had the 1970's Botterill, Hartston, Keene Batsford book on this, but have since dispensed with it.} 4. e4 d6 5. f4 {I have quite liked this four pawns attack, not least because I have outperformed my grade OTB with it , but also because it slows up Black's f5 ideas} c5 {This is a move earlier than I remembered but it must be alright} 6. d5 e6 7. Ng1f3 exd5 8. cxd5 O-O 9. Bf1e2 {I think this is now a Benoni four pawns. Whatever.} Rf8e8 {Immediately emphasizing the weakness of the e pawn and suggesting White should have played Bd3} 10. e5 {This sacrificial idea was analyzed in the Botterill book but I'd be lying if I said I remembered very much of the detail. Nd2 or Qc2 are probably sound alternatives.} dxe5 11. fxe5 Nf6g4 12. e6 fxe6 {White now has the kind of open position he wants with good access to the open lines for the pawn. Black may have problems developing his queenside} 13. Bc1g5 {With a gain of tempo} Qd8a5 {Looks reasonable and threatening 14 ...Bxc3+ 15. bxc3 Qxc3+ going two pawns up with a nasty looking attack} 14. O-O {Retreating the king, bringing the rook to the f file and daring him to exchange off the bishop guarding the dark squares near his king} h6 {Not entirely sure about this in hindsight. The Black queenside is not getting into the game.} 15. Bg5f4 {Attacking c7 suggesting that the knight on c3 may go there in the very near future} exd5 {I think he is worrying about the knight on g4 and opens lines on the e file to allow it back to the centre as well as gaining it protection from the c8 Bishop.} 16. Nc3xd5 {This felt fine threatening Nc7 and preventing Qb4 forking Bishop and b pawn} Ng4e5 {Although I didn't realize for two moves this turns out to be a mistake. I'm not sure what Black should play. He clearly wants to block the f4-c7 diagonal but misses Qd6} 17. Nf3xe5 {I reasoned that I was exchanging off one of Black's developed pieces as well as increasing the influence of the rook on f1} Bg7xe5 18. Bf4xe5 {I deliberated here for a while about Bxh6 recovering the pawn but failed to find anything concrete. I then looked at this and realized I had Nf6+ and Qd6 at the end of the sequence} Re8xe5 19. Nd5f6 Kg8g7 20. Qd1d6 Re5e6 {Here Rxe2 is no different} 21. Nf6e8 {Back resigned here. I had calculated the following finish} Rxe8 22. Qf6 Kg8 {Kh7 Qf7+ transposes} 23. Qf7 Kh8 24. Qxe8 Kg7 25. Rf7 1-0 {A fun game that shows the potential of this pawn sacrifice.}

[FEN "rnb1r1k1/pp4bp/4p1p1/q1pP2B1/6n1/2N2N2/PP2B1PP/R2Q1RK1 b - - 3 14"]
14. ... c4 {now if Bxc4 Qc5+ picks up the bishop (Bg7 guards d4) so if white plays something neutral like} 15. Rac1 {then} Qc5 16. Kh1 Nf2 {looks like business}