I notice that Panczyk and Ilczuk considered it (with an exclam for 20. a4) += in their 2009 book.

You know, there hasnt been much (I didnt see any when I went over this thread) discussion on 18. Bb5 19. Rc6 20. a4 with the idea of saccing the exchange if black threatens with Bd7. I have no idea how I should respond to it as black, and haven't lost a blitz game with it as white. Ive seen a GM and a few FMs play it with complete success as white, I'd like to know how to hold against it.

Hi! after a long time

I was wondering why not after

1.  d4 Nf6 2.  c4 g6 3.  Nc3 Bg7 4.  e4 d6 5.  Nf3 O-O 6.  Be2 e5 7.  O-O Nc6 8.  d5 Ne7 9.  Ne1 Nd7 10.  Nd3 f5 11.  Bd2 Nf6 12.  f3 f4 13.  c5 g5 14.  Rc1 Ng6 15.  Nb5 Rf7 16.  Ba5 b6 17.  cd6 cd6 18.  Be1 a6 19.  Nc3 a5 20.  Nb5 Bf8 21.  Rc3 g4 22.  Qc2  not gf3 but go all in with

22...g3!? 23. hg3 Nh5 24. gxf4 exf4 without fearing

25. Nc7 Rb8 26. Ne6 (this is the idea isnt it?) Be6 27. dxe6 Rg7 28. Qb3 Qg5 (simply go for the king. material is irrelevant here) 29. e7+ Kh8 30. exf8=Q Nxf8 31. Rf2 Ng3 32. Nxf4 Qxf4 and although the comp says = i am not sure if in those thousand of variations black may not find a win and whats more its not a position to play OTB

Another funny variation, that says that white's position is very dangerous is

25. Bf2 Bd7 26. Nc7 Nh4! 27. Bh4 Qh4 28. Qa8 Rg7 29. Ne1 Rg6! and now white has to rescue himself with the stunning Rc8! 

There are many side variations of course but the general idea is the same. Play towards the king and the evaluation changes in  MOST cases. I really like the g3 approach more. Its an all in approach, that i don't think white would appreciate.

Matemax wrote on 02/15/12 at 14:13:28:

After black's ...f5, if white has played f3 what extra option black gets if he keeps the tension rather than ...f4? fxe whill be followed by f3 and I do not see it giving anything substantial to black. White has more space in queenside and kingisde will now become equally controlled and black's dark square bishop is definitely the worst piece on the board.

1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. Ne1 Nd7 10. Nd3 f5 11. f3

I have a thought here after either 11 ...f4 or 11 ...Kh8 and maybe even after 11 ...Nf6, can White play with the idea of Kh1, Rg1, Bf1, Bd2-Be1-Bf2 with b4 as needed and then pursue the queenside. Is there a mating attack I'm missing, because it seems to me White can shore up his kingside and play on the queenside at his leisure? And possibly look for kingside breaks of his own.

Cheers, Allan

1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. Ne1 Nd7 10. Nd3 f5 11. f3 f4 12. Bd2

Taking this move order as the standard one to reach this position.  If Black intends to redeploy his knight as in the Shirov DVD system advocated (here) by Amen, is there any reason to rush with ...f7-f5?  It doesn't force f2-f3, obviously, since the alternative move order 11. Bd2 Nf6 12. f3 is available, and Black has then committed to Nf6.  So Papageno's move order point below seems right, if black is looking to play the Bologan/Shirov, rather than Vigorito, line.

So why not 10...Kh8, holding out the option of playing the knight to g8 and h6 (or theoretically f6) before advancing on the kingside?

The idea appears to have been played by Monika Socko in 2006, but her opponent chose the (not challenging) 11. Bd2.

Come on !! I had this exact question with Bologan's book (...Kh8) in one hand and Vigorito's book (...f4) on computer. After a lot of deliberation, I chose f4 as I literally learnt KID by following Vigorito's lectures in Chesslecture.com. Took me some intense study to pick it up. 

And now you are saying Kh8 is the best move !! 

Glad you like - and I generally agree. The ...a6/...a5 plan is the major try advocated by engines, but isn't particularly in line with the demands of the position. I don't think it's Black's best, at least not at the current time.