My variation in the London system against the King's indian defence

1. d4 Nf6 2. Bf4 d6 3. e3 g6 4. c3 Bg7 5. Be2 O-O 6. g4!!

I've started to play this variation successfully in real life tournaments with great results, the purpose is to proceed with an immediate attack against black's King's indian defence. Despite of your modules analysis, please tell me what you humanly think about it.

London system. The Montanari variation.

Here you have an example:

1. d4 Nf6 2. Bf4 d6 3. e3 g6 4. Be2 Bg7
5. c3 O-O 6. g4 Nbd7 7. Nd2 b6 8. g5 Ne8
9. h4 Bb7 10. Bf3 Bxf3 11. Ngxf3 c5 12. h5 Nc7
13. Qc2 Nd5 14. hxg6 fxg6 15. Qb3 e6 16. Bxd6 Rf7
17. Kf1 Nf8 18. Bg3 Ne7 19. Be5 Qd5 20. Bxg7 Kxg7
21. e4 Qd6 22. Ne5 Rf4 23. f3 Nd7 24. Nd3 Rf7
25. Kg2 Raf8 26. Nc4 Qc7 27. Nce5 Nxe5 28. Nxe5 Nc6
29. Nxf7 Qxf7 30. Rh3 Qe7 31. Qa4 Qd7 32. Rah1 Rh8
33. f4 Qd6 34. Qa6 Qc7 35. dxc5 bxc5 36. f5 exf5
37. exf5 gxf5 38. Rh6 Ne5 39. Qf6+ Kg8 40. Qe6+ Kf8
41. Qxf5+ Kg8 42. Rf1 Nf7 43. Qe6 Kg7 44. Qf6+ Kg8
45. g6 Kf8 46. g7+ Ke8 47. gxh8=R+ Nxh8 48. Qxh8+ Ke7
49. Qg7+ Ke8 50. Rf8#

g4 is not a losing move, but it's also not really threatening anything. You need h4-h5 to actually crack at the kingside structure.

The general rule when your opponent is attacking on the wings is to open up the center. So black should probably just play Re8 and bust open the center with e5 as soon as possible. You should also note that after you are committing to g4, it's clear you're not going to be castling kingside, so black's play has focus. Your play has focus too, but it's hard to play so aggressively without development (and your king stuck in the center).

Yes, g4 sounds a bit strange.Maybe h4 can be an option.Aniway, g4 ...h5 and i like black position (he did not castle yet).

What if no ...Nf6? I will play e7-e5 as soon as move 5. Go ahead, make my day! :D

lichess.org/forum/game-analysis/neutralizing-the-london-bishop#1

@Volibear47 That line looks interesting but I recommend playing 3.Nc3 against g6 setups by black

Thank you for your polite and sincere answers !

@Volibear47 also it's worth being aware that the main line is 1.d4 Nf6 2.Bf4 c5. Some GMs recommend to play 1.d4 Nf6 2.Nf3 instead because of this

2.Nf3?! goin‘ for LS?

1.d4 Nf6 2.Nf3 b6 3.Bf4 Ba6!! is my recommended London buster.