MrCookie wrote on 12/04/10 at 16:23:39:
1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 O-O 5. Bg2 d6 6. O-O Nbd7 7. Nc3 e5 8. h3 *
Just wondering what you avoid with this move order.
It's just to control g4!
In many lines White wants to play Be3 without being hassled by ...Ng4.
White has a static advantage based on having more space and so generally in the early middlegame he just wants to stabilize the position and suppress possible dynamic counterplay.
Black's main counter-attacking piece is the g7-bishop, which can suddenly "fire" as soon as the f6-knight moves out of the way. By playing h3 White ensures that when that piece moves it will not be able to come forward to the aggressive g4 square - one less square to worry about..
Look what happened when Botvinnik tried to do without this move:
[Event "World Championship 20th"]
[Site "Moscow"]
[Date "1954.04.15"]
[Round "14"]
[White "Botvinnik, Mikhail"]
[Black "Smyslov, Vassily"]
[Result "0-1"]
[ECO "E68"]
[PlyCount "66"]
[EventDate "1954.03.16"]
[EventType "match"]
[EventRounds "24"]
[EventCountry "URS"]
[Source "ChessBase"]
1. d4 Nf6 2. c4 g6 3. g3 Bg7 4. Bg2 O-O 5. Nc3 d6 6. Nf3 Nbd7 7. O-O e5 8. e4 c6 9. Be3 Ng4 10. Bg5 Qb6 11. h3 exd4 12. Na4 Qa6 13. hxg4 b5 14. Nxd4 bxa4 15. Nxc6 Qxc6 16. e5 Qxc4 17. Bxa8 Nxe5 18. Rc1 Qb4 19. a3 Qxb2 20. Qxa4 Bb7 21. Rb1 Nf3+ 22. Kh1 Bxa8 23. Rxb2 Nxg5+ 24. Kh2 Nf3+ 25. Kh3 Bxb2 26. Qxa7 Be4 27. a4 Kg7 28. Rd1 Be5 29. Qe7 Rc8 30. a5 Rc2 31. Kg2 Nd4+ 32. Kf1 Bf3 33. Rb1 Nc6 0-1