Queen's Indian Defense question that has me stumped After the moves 1.d4 Nf6 2.c4 e6 if White plays 3.Nf3, Black often plays the Queen's Indian Defense with 3...b6. But if White plays 3.Nc3, then Black rarely plays 3...b6. 

 [FEN ""]

  1.d4 Nf6 2.c4 e6 3.Nc3 (3.Nf3 b6) b6!?


Does anyone know why that is? (assuming GM level play)
The simple reason is because 3...b6 doesn't prevent 4.e4! when White immediately grabs the center. 

   [FEN ""]

   1. d4 Nf6 2. c4 e6 3. Nc3 b6 4.e4!


The bishop on b7 isn't very effective in the kind of pawn structure that arises after e4. Often, White may play f3, strengthening the e4 point and completely blunting the bishop on b7. 

Consider this structure - 

   [FEN "4k3/pbpp1ppp/1p2pn2/8/2PPP3/2N2P2/PP4PP/4KB2 w - - 0 1"]
   [Event "Bishop on b7 is blunted by White's pawns on e4 and f3"]


Black may want to break White's center with a move like d5, but that allows White to play e5, driving away the knight on f6 with tempo and also establishing a strong pawn on e5, which may enhance White's attacking prospects on the kingside, as I discussed in point number 4 of this post.  

  [FEN "4k3/pbpp1ppp/1p2pn2/8/2PPP3/2N2P2/PP4PP/4KB2 b - - 0 1"]
  [Event "The threat of e5 is always looming after d5"]

  1... d5 2. cxd5 exd5 3. e5 


Black may also want to play c5, but in those positions, after a move like d5, the position transposes into Benoni type positions where the bishop is completely misplaced on b7, thus Black loses at least a tempo. Besieds, b6 might also be a waste of time in some Benoni positions. 

   [FEN "4k3/pb3ppp/1p1pp3/2pP4/2P1P3/2N2P2/PP4PP/4K3 b - - 0 2"]
   [Event "Unfavorable transposition to a Benoni type position"]


Recommended Games - 

The following games in this line are quite instructive - 

Harry Nelson Pillsbury vs Heinrich Wolf, 1902 1-0

   [White "Harry Pillsbury"]
   [Black "Heinrich Wolf"]
   [Date "1902"]
   [Result "1-0"]
   [FEN ""]    


   1. d4 Nf6 2. c4 e6 3. Nc3 b6 4. e4 Bb7 5. Bd3 d5 6. cxd5 exd5 7. e5 Ne4 8. Nf3 Be7 
   9.  O-O O-O 10. Qc2 Nc3 11. Bh7 Kh8 12. bxc3 g6 13. Bg6 fxg6 14. Qg6 Qe8 15. Qh6 Kg8 
   16. Ng5 Bg5 17. Qg5 Kf7 18. f4 Ke6 19. f5 Kd7 20. Qg7 Kc8 21. e6 Rg8 22. Qh7 Rh8 
   23. Qg6 Ba6 24. Qe8 Re8 25. Re1 Nc6 26. Bg5 Nd8 27. Bd8 Kd8 28. f6 Rh8 29. Re5 c6 
   30. Rae1 Rc8 31. Rg5 Bd3 32. Ree5 Rh6 33. Rg8 Kc7 34. Rc8 Kc8 35. e7 Bg6 36. e8=Q 1-0


Efim Geller vs Mark Usachyi, 1957 1-0

   [Event "UKR-ch"]
   [Date "1957"]
   [White "Geller, Efim P"]
   [Black "Usachyi, Mark"]
   [Result "1-0"]
   [FEN ""]

   1. c4 Nf6 2. Nc3 e6 3. d4 b6 4. e4 Bb4 5. Bd3 Bb7 6. f3 O-O 7. Nge2 d5 8. cxd5
   exd5 9. e5 Ne8 10. O-O c5 11. a3 Ba5 12. b4 cxb4 13. Na2 Nc6 14. Rb1 bxa3 15.
   Bxa3 Ne7 16. Ng3 g6 17. Nc1 Bc6 18. Qe2 Ng7 19. f4 Re8 20. f5 Nexf5 21. Bxf5
   gxf5 22. Nb3 Qg5 23. Rf3 Rac8 24. Rbf1 Ba4 25. Nxf5 Rc3 26. Nxg7 Qxg7 27. Nxa5
   Rc2 28. Qxc2 Bxc2 29. Nc6 Qh6 30. Rg3+ Bg6 31. Ne7+ Kh8 32. e6 Rxe7 33. Bxe7
   fxe6 34. Rc3 Be8 35. Rc8 Qe3+ 36. Kh1 Qe2 37. Rxe8+ Kg7 38. Ref8 h5 39. Bd6 h4
   40. Be5+ Kg6 41. h3 a5 42. Rg8+ Kh5 43. Rf7 1-0


Phillip Viner vs Elias Castrillon, 1964 1-0

   [Event "Tel Aviv ol (Men) fin-D"]
   [Site "Tel Aviv"]
   [Date "1964"]
   [Round "5"]
   [White "Viner, Phillip"]
   [Black "Iniguez Castrillon, Elias"]
   [Result "1-0"]
   [FEN ""]

   1. d4 Nf6 2. c4 e6 3. Nc3 b6 4. e4 c5 5. d5 d6 6. Bd3 Nbd7 7. f4 exd5 8. cxd5
   Be7 9. Nf3 O-O 10. O-O a6 11. a4 Bb7 12. Bc4 Qc7 13. Re1 h6 14. e5 Nh7 15. b3
   Rfe8 16. Bb2 Ndf8 17. Qd2 Ng6 18. Rad1 Bf8 19. Ne4 Qd8 20. Nxd6 Bxd6 21. exd6
   Qxd6 22. f5 Nf4 23. Be5 Rxe5 24. Rxe5 g5 25. fxg6 Nxg6 26. Qxh6 Nf6 1-0