b3 in the advance french

This has been my weapon when I have faced the french.

1.e4 e6 2.d4 d5 3.e5 c5 4.c3 Nc6 5.Nf3 Qb6 6.b3!?

Or 4.b3

The idea is to develop the bishop to b2 to hold the center.  The idea is to cramp black and take away his counterplay.  White wants to advance on the queenside taking away black's counterplay, and switch to the kingside to attack the black king.  If it is played correctly, black will have a difficult game.

I think   after

6.b3.....cxd4   7.cxd4...Bb4+   -+

  if   8.Bd2 or Nd2 ............Nxd4 wins a pawn

I have prepared for that with a surprising move I used in a game.

6...cxd4 7.cxd4 Bb4+ 8.Ke2!?

This works as the pawn is maintained and the king is relatively safe in the center.  The black bishop will be used to gain a tempo on the queenside squeeze.

there is a variation in the french

 1.e4...e6   2.d4...d5   3.Nd2...Nf6    4.e5..Nfd7    5.f4..c5   6.c3...Nc6

7.Ne2!..Qb6   8.Nf3...cxd4   9.cxd4...Bb4+   10.Kf2!

      I am assuming this is where you got the idea from .

   Very interesting I looked at Ke2 when I made my recomendation for black but thought that whites king is not as good on e2 as it is on f2 but the center is blocked. I was just looking for a good reply for black and i certainly dont see a kill. Very creative! Very cool. I still like black but its harier than i thought

good luck with the variation post a game if you get this line I think it would be an interesting post

Well, I am going to be in a state championship tournament this weekend so hopefully I get the French and I can post a game.

Black will have a difficult game if played correctly?? Black has two good ideas, the first one was already mentioned: ...cxd4 cxd4 Bb4+ and Ke2. Now there is a similar line to this, except I think the bishop moves and the king has access to f1, a much better square. In the line aijp posted it looks pretty nice for black. the attack on d4 is going strong and black will soon play ...0-0 and ...f6 and he's way ahead in development. Meanwhile white's development, already sluggish will be revolved around defending d4 which is rather passive. However, another good idea for black is simply to play for ...f6 attacking e5, when b3 seems rather out of place compared to quicker developing moves. So I don't think it's very good. b3 should only be played when absolutely necessary to defend d4 that way.

Well after f6, my plan has been to develop the bishop to b2.

The bishop on b2 can help with the defense of e5 which is the critical point for white.  At the same time, it defends the rook at a1 so that a queenside expansion is possible without the pin on the rook.