1. d4 Nf6 2. c4?!

Well. one can only say it isn't tried often... post some results if you play it.

The fact is : with this set-up, white can't put enough pressure on the d5 pawn - black can freely develop and protect d5 with his e6 and c6 pawns. The pawn push c4 increases this pressure.

I think I see now, but I'm a bit hesitant with the pawn formation and queenside weaknesses if black decides to trade knights.

an ideal center for white is e4+d4... but black shouldnt allow this. so when white plays 1.e4, a lot of times they try to build up a d4 push later on.

whereas with 1.d4, e4 is harder to get in. white settles with c4, which is almost as good.. and the good thing about it is pretty much every line they will get it in and get developed.

To me the variation I came up with gives a solid position after the fianchetto, kingside knight move, and then castling. The 'aggressive' c4 harms your pawn structure and somewhat weakens your own position.

black will get a slight edge out of the line, due in part to eventually playing ..c5 and grabbing more space. your queen will also have a hard time finding a home

whoops didnt mean for it to be a puzzle sorry. just a sample line for avk

Jarkov basically says it here. In the symmetrical kingspawn openings (1. e4 e5) white has 2 possible pawn breaks to undermine blacks centre: d4 and f4. Because d4 is supported by the Queen it's usually easy to carry out whereas f4 might weaken white's king. So, d4 is the more common break here.

In the symmetrical queenspawn openings (1. d4 d5) white also has two possible pawn breaks: e4 and c4. This time c4 is the more common one, because e4 is hard to carry out without the support of the queen and c4 doesn't weaken white's king if it castles short. After 1. d4 Nf6 it's possible to play 2. Nc3 but then black can transpose to symmetrical queenspawn openings with 2... d5! and Nc3 hampers white's natural pawn break c4. Therefore it's considered more ambitious to play c4 before Nc3.

Actually there's a general rule of thumb saying that in queenspawn openings you should not block your c-pawn with knight without a very specific reason (this rule applies also when playing with black).

One point that is being overlooked is that in many lines if White neglects to play c4, then it is Black who will play c5 and challenge the center.

I'll let you explain that one to the hundreds of grandmasters who routinely play 1. d4 Nf6 2. c4 as white.

I think it was a facetious comment promoting the Budapest Gambit...

white would love to trade the cpawn for the dpawn since the cpawn doesnt affect the center as much. d and epawns are powerful pawns giving control in the center.

thanks, this is was basically the point of my line, but I forgot to put it in the end evaluation.

Jarkov, this variation looks favourable to white. However, I feel I may have overlooked something. . .please tell me if I have.

C4 asserts more control over the center. It's what white usually does to preserve the advantage which is otherwise usually given away.