The Not-So-Hanging Pawns
While the Isolated Queen Pawn (IQP) structure is probably the best-known general structure, the closely related structure of Hanging Pawns is also quite important.
For the serious player, I think it's quite useful to study typical middlegame patterns and pawn structures. Even if you don't play IQP or hanging-pawn structures in the normal course of your games, a grounding in such structures is useful as they can arise from all sorts of openings and in surprising ways. Having a foundation in the typical ideas will give you a leg up on your opponent (or at least level the playing field). Here's a typical Hanging Pawn structure that arises from the Nimzo-Indian, but it surprisingly can also arise from a Semi-Slav as in the game below.
Strangely enough, we've transposed into a Nimzo-Indian Rubinstein (4.e3), where White has an extra tempo! This is because Black lost a tempo with ...c7-c6-c5 in the opening phase. Although I didn't really need to know this to play the position, it was a useful bit of info - I play the Rubinstein Variation of the Nimzo while Cori doesn't play the Nimzo, so I could be satisfied from a practical point of view and an objective point of view (I think White is better here).
With his pawns on c4 and d4, Black has no real central squares for his knights. Meanwhile, White has a number of possible plans. His most common plan is to complete his development and then push forward with his d-pawn (d5 in this case, or ...d4 with black) in order to open things up for his pieces (especially the bishops). He has other ideas too: if he moves the Nf3, he can think about f2-f4-f5. He can also play on the queenside with a4-a5, softening up the b6-pawn. Black's traditional plan is to put his queen on f4, but by retreating my knight to d2 and then playing Qe3, Cori faced a tough decision - exchanging queens would leave my potentially weak center strengthened, while moving to h4 leaves it a bit out of play after h2-h3.
Now here's the actual game:
Question 1: Black wants to add some pressure to d4 with ...Nc6 next. What would you play here as White?
And here's the entire game in one viewer: