I dont know about refuted but I remember looking into this myself at some point and the problems I saw was white playing things such as
4. c3 and Ba6 right away is a blunder you know 5.Bxa6 Nxa6 6.Qa4+ winning the Knight
As a matter of fact you cannot achieve this trade on a6 till first you secure c6 and a6 so that firstly you can survive the trade on a6 and the subsequent Qa4+ that will follow threating to win whatever is sitting on a6
Combine this with the idea that if white really doesnt want to trade the light squared bishop he always has plans with just playing
either Bb5+ followed by Ba4 Bc2 and Ne2 so that he keeps his bishop and castles
or just white plays just Bd3 then to Bc2 and Ne2 and castles with the same effect
It is not that b6 is bad and indeed you might catch many 1.e4 players by surprise but for the long term id look at playing the mainlines and just keep an eye out for opportunities to play Bd7 Qb6 and Bb5 trading off the light squared bishop or lines where black plays the manuaver Bd7, Be8, f6 then maybe Bh5 or Bg6 looking to either trade there or just to defend the kingside which might not be a bad idea. So ya id agree with your friend it only seems nice to trade it off early youll prolly be better off using it to defend the kingside or trading it down later through one of the maneavers I mentioned above.
Is 3...b6 acceptable in the French Advance?
1.e4 e6 2.d4 d5 3.e5 Bd7 4.Nf3 a6 is the popular way to try the same idea, intending bd7-bb5. Avoids bb5ch, and the knight being displaced. There is a similar idea after 3...c5 4c3 Bd7 5Nf3 a6. There can be some problem with this later line when look at details, see this thread
https://www.chess.com/forum/view/chess-openings/french-defence---rubinstein-variation
DEFCON_1 wrote:
It's the main recommendation in Neil McDonald's How to Play Against 1.e4, he recommends the move 3...b6 against the Advance variation of the French. However my friend who himself is pretty good at the game says that trying to trade off the bad bishop is 'too slow' and gives white an advantage in the end. I realize the book is some years old, but surely 3...b6 is refuted or something, no?
I'd probably agree with your friend. While the LSB trade probably helps, it does probably take too long allowing white good initiative.
Tougher on black is usually king safety. Kside is pretty bare with white potential and qside often is somewhat open and white already 0-0. Maybe black still has drawing chances but not sure much winning chances against even decent play.
When ...b6 is planned, moves like ...Ne7 and ...Qd7 are sometimes prep I believe.
It's not refuted and it's a very playable line, but you've got to watch out for cheapos like Qa5+ picking up the bishop on a6 which is why if black plays any move which opens up the Q along the d1 to a5 diagonal Qd7 should be played first. But's it's absolutely playable and a good way of throwing your opponent out of book.
Saying that, I agree with some of the above claiming that it's not a 'bad bishop' if it's used correctly and I guess you've got to ask yourself is it worth investing that much time for black just to get into an equalish position by trading off the bishop? I don't know enough about it to answer that question tbh but it certainly is a playable and interesting line and has been played by top GM's.
When black plays 3...b6 white can happily trade the bishops and then play 6. Bg5 which is a pretty strong line .. black has to play carefully after that and in fact if white pulls off some good moves, white holds a 1+ point advantage in this opening line with no problems. Black cannot castle kingside and even if black castles on the queenside, I believe white can bring to bear some pressure on the h file by doubling rooks. Here is a sample variation. In my opinon, black playing 3...b6 is not worth it and will in a lot of cases bring him trouble, if white plays well!
It's the main recommendation in Neil McDonald's How to Play Against 1.e4, he recommends the move 3...b6 against the Advance variation of the French. However my friend who himself is pretty good at the game says that trying to trade off the bad bishop is 'too slow' and gives white an advantage in the end. I realize the book is some years old, but surely 3...b6 is refuted or something, no?