Beginner's Nimzo-Indian

The purpose of 3.Bb4 is that you want to trade your bishop for their knight, right? Double the pawns? So why is it after they play the rubinstein/kasparov or anything other than classical you aren't supposed to trade immediately? This would double his pawns which is the purpose of the move.

Because the point of the Nimzo-Indian is NOT to trade the Bishop for Knight and double the pawns.  There are certain lines where that occurs, and the c4-pawn can be weak, but that is not the reason for 3...Bb4.

The reason is the same reason for many other QP openings.  1.d4 d5, what is Black doing?  Preventing e4.  1.d4 Nf6, what is Black doing?  Preventing e4.  1.d4 Nf6 2.c4 g6 3.Nc3 (threatening e4) d5 (Preventing e4)

Well, the same is the case for the Nimzo-Indian.  1.d4 Nf6 2.c4 e6 3.Nc3.  White now threatens 4.e4, hence why 3...b6 is a bad move here, and that only works against 3.Nf3, where White doesn't threaten e4 and Black can take 2 moves to play b6 and Bb7 (controlling e4).

So now, why do you think Black plays Bb4?  To stop e4!  With the Knight pinned to the King, the Knight doesn't promote an e4 push.

Nge2 is kinda toothless because black can equalize easily with d5 a3 Be7 with a QGD position where white's knight on e2 and bishop on c1 are placed poorly.

Actually, 3... b6, the queen's indian defense, is a very credible opening.

I see, that makes sense. Thx

yes.. but 3.. b6 cannot be played against 3. Nc3 because of 4. e4 where black has given up the center for nothing. 3.. b6 the queens indian should only be played against 3. Nf3 because white cannot play e4 as quickly

It is a pleasant position for white, but black should be able to hold after d6, normal development, and an eventual e5 or c5. Plus, the provocative nature of black's opening choice can lead to quick knockouts against a fragile-minded first player.

Indeed, e3 and Nge2 is topical, popular, and a very sensible way to fight for an opening advantage for white. What I am saying is that if I am on the black side and my opponent plays with e3 and Nge2, I will be pleased with my chances to attain full equality.

b6 can be good instead of Bb4, if you want to transpose it into an Owen's defence line.

Not against 3.Nc3 it isn't!

1.d4 Nf6 2.c4 e6 3.Nc3 b6 is HORRIBLE
1.d4 Nf6 2.c4 e6 3.Nf3 b6 is the Queen's Indian, and a VERY WELL RESPECTED LINE and PLAYED BY MANY GMS!

Once again, it's all got to do with e4.  After 3.Nf3, it will still take another move to promote an e4 push, so Black has time for 3...b6, answering 4.Nc3 with either 4...Bb7 or 4...Bb4, both of which stop e4.

Why is 1. d4 Nf6 2. c4 e6 3. Nc3 b6 horrible? Yes, white gets to play e4, but what does that do in and of itself?

Just stop right there.. You admit it is a "pleasant position" for white?

It can be argued that some of the most important ideas in this opening are to avoid pleasantries for white. That's why it's widely thought of as one of the most annoying systems to play against in the QGD.

Why is 4. e4 horrible? Well it's not horrible. It's just far and away from black's best. Because the main ideas around most QGD lines (including the Queen's Indian) revolve around preventing e4. You just let your opponent accomplish his long-term plan only 4 moves into the game.

White now has a space advantage and a very strong center, and the only clear target black really has is the pawn on e4, which is easily defended.

I totally agree, but the provocative nature of black's opening choice can be dangerous unless white keeps a cool head, which is a necessity that is easier said than done.

That is a very interesting idea.

To add to the answers to the original question: even if you do want to take on c3, there's no reason to do that now -- might as well wait for white to use a move on a3.

If you are basing validity of "White doesn't know it as well" or "White must keep a cool head", then you don't understand chess.

If you live in a town with only 4 cops, are you going to do 100 in a 35?

If you have a teacher that clearly has his eyes on the girls, and you are a boy, are you going to cheat on his test?

If you have a parachute that has never failed for you, are you going to jump out of an airplane with no backup?

After 1.d4 Nf6 2.c4 e6 3.Nc3, White may have memorized lines deeper against the Nimzo-Indian (3...Bb4), QGD (3...d5), and Modern Benoni (3...c5), but that doesn't mean that lesser known inferior lines should be played simply because there is a "chance" that White doesn't know what to do. 

Taking the "I can play this move, and I'll have the better position unless White finds Ba3, in which case then I'm lost.  That move appears to be somewhat concealed.  So I'll go ahead and play this move" approach will fail you in the long run.  If Ba3 busts your idea, find another move.  The same thing goes for openings.  Assume that your opponent knows what he's doing.  If it turns out he doesn't, well all the more power to you, but the moment you start depending upon your opponent not knowing what he's doing is the moment you will fail.

Well said.

Is this position bad. I know all of blacks other moves are no problem but didn't find much info on d5 for black?