does Nimzo violates theory?

hi. in Nimzoindian generally black exchanges his bishop for whites knight, but it is taught to youngsters that:

1. a bishop pair is better than a knight pair

2. after exchange white get doubled pawns, but they are towards the centre and early in the game, so not a liability

3. then white also gets an open b-file

so how come it is the most solid defense against d4 ?

Well the Nimzo Indian creates a minor piece imbalance to play for. And it doesn't always give white doubled pawns btw like in the 4. Qc2 variation...

Often white will emerge with a normal opening advantage.

But many, including myself, hate facing the Nimzo Indian. Its unfortunate that as a QGD Exchange player I must play against it...lol

sir. i was expecting a good reply from you. plz explain!

Does violates violate grammatical rules?

Yes, and I hate opening principles

On the other hand I may be called a hypocrite, without those boring Lasker/Steinitz guys tediously writing out the Ten Opening Commandments our chess games would still look like the 1. a4 2. Ra3 type. Although now thinking about it I don't actually see why that would be a particularly bad thing, the kids don't seem to mind much either.

In fairness to the OP, he is only asking. I'm curious as well.

When is the last time the OP received a more satisfying answer than an in between question like this one?

"hi. in Nimzoindian generally black exchanges his bishop for whites knight, but it is taught to youngsters that: 1. a bishop pair is better than a knight pair"

The Nc3 knight plays an important role in the QG. After x the knight on c3, black has an extra hold on d5 and e4 in the centre. So he often developes his white Bish to b7 (of course that is just one variation).

And a bishop pair is stronger only in open positions. However understanding the imbalance created by BxN is really the key.

All these principles like "doubled pawns are bad", "Bishop pair is good" are very nice but in practice you often have to weight several such principles against each other. For example in Nimzo it's often a very difficult question which one is more important the weaknesses in white's pawn structure or the dynamic potential of the bishop pair.

In general black's long term prospects tend to be excellent if white doesn't act agressively enough (often sacrificing in the process) as the game shown by Conzipe demonstrates. Regarding this I'd like to cite Graham Burgess commentary for the game Geller-Euwe, Zurich 53: "In effect then, the Sämisch Nimzo-Indian (4. a3) is a gambit by white: the c4 pawn is undead rather than alive, and white must act with all the urgency that gambit play entails". I found this comment rather instrucitve. The Nimzo with doubled pawns often leads to very complex and double-edged play with chances for both players.

Don't let general principles become dogma. Its strange to me that I have never been a big fan of the nimzo when playing black and yet love to play the winawer french as black..... go figure. 

thx. at last you understood what i really meant!

hi. that is why i think Nimzoindian is better than both KID and Grunfeld because it does not allow white to make a classical pawn centre.

Do you really?  I  ventured to critique those principles (well, in fact what I did was to mention that I thought an actual critique of them would be a good thing as i didn't think they were as helpful to beginners as is generally supposed... ) and I quickly found myself pelted with small rocks, bits of gnawed bone, feces pellets (dried and fresh) & etc.,  whatever the squat grunting flat-faced cave people that populate this region had on hand... 

Those were never intended to be "principles" or "commandments" but only general guidelines to help beginners get some sense of direction.

Heathen! Caissa shall smite thee!