Hmmm ig maybe its cause of qb6 ideas
c3 vs c4 in the London

Studying the infamous London, why is c3 preferred over c4? Doesn’t c3 just overprotect?
c4 is playable, but kind of messy, since it puts both the c and d pawns under immediate tension.
After ...Bg4, Black has a comfortable opening position, while White is a bit on the defensive.
Everything can get loose and sloppy quite quickly, which generally isn't what London players want.
For example:
Or, if white wants to keep things neat and tidy, to avoid all the loose and sloppy possibilities, then black comes out of opening quite comfortably and happy.
For example:
c3, instead, keeps white's clamp on the center and allows the London player to continue with his usual plans, without giving black any room for messy complications.

I love messy complications, not ones that give my opponent an advantage, though. Hmm. I’ll try to analyze it later.
Magnus (2850): Play Bc4 here.
Someone (1400): Why not play Bc6?
Well, in this situation an expert is saying to play that move.
Stockfish (3750): Play c4
InsertInterestingNameHere (1500): Why not play c3?
This is the most important and common reason. Just trust stockfish I guess.

I never said that lmao. I said “why not play c4”, and I just wanted to know the reasoning behind why people don’t play it. Well now I know it’s because of Bg4. Knowing the reasoning behind bad moves will help me get better moreso than “just play c3 because it’s good”. Knowing why something is bad is, I would argue, equally as important as knowing why something is good.
In general, London players play c3 to solidify the center, which makes the resulting positions easier to play. With c4, you'll be creating lots of tension in the center early on where your pieces are not necessarily well placed for this confrontation (DSB no longer on c1 guarding b2, DSB could get hit by Nd5 in some cases, etc) and you'll have to be careful not to end yourself in trouble, if not already.

Alright, well now I know why I’m absolutely terrible at chess. Thank you for the explanations, everyone!
I never said that lmao. I said “why not play c4”, and I just wanted to know the reasoning behind why people don’t play it. Well now I know it’s because of Bg4. Knowing the reasoning behind bad moves will help me get better moreso than “just play c3 because it’s good”. Knowing why something is bad is, I would argue, equally as important as knowing why something is good.
That’s a complete joke when I commented that.. I even get that you wanted to learn ‘why’ behind the moves

Studying the infamous London, why is c3 preferred over c4? Doesn’t c3 just overprotect?
it's just a bad queen's gambit lol
there are QG lines with Bf4, but the knight is on c3 and not d2.
In your diagram, black can force an IQP by force, where the bishop on f4 is misplaced after something like ...Bg4 and ...dxc4 and ...cxd4


If you're going to play c4, you should play it as Queen's gambit where you can develop the knights quicker.
I think the difference is that White has not developed Nc3 to pressure the center yet, and has instead wasted time with Bf4, e3. Meanwhile, Black gains enough center space with d5 c5 to completely counteract White's c4 push.
So in the case of the London, it is quite obviously more favorable to support the d4 pawn with c3 and Nd2 instead of a late c4 Nc3. One of the only cases c4 is good in the London is after Bf5 to enable Qb3.
Studying the infamous London, why is c3 preferred over c4? Doesn’t c3 just overprotect?