woooooah
London System Theory for early …c4

Instead of e6, black can play c4 immediately. I studied the deep lines, I even have a collection on it.
1. d4 d5
2. Bf4 c4
After these lines, the London is often borderline refuted/punished.
c5 is a decent move but Black isn’t going to get more than equality without inaccuracies from White. The London may not be great for getting an objective advantage but there is no “refutation”

Instead of e6, black can play c4 immediately. I studied the deep lines, I even have a collection on it.
1. d4 d5
2. Bf4 c4
After these lines, the London is often borderline refuted/punished.
If you meet the London like that, then you will get a warning from the ref for your illegal move 2...c4.
# different possible strategies when white plays ...c4:
- Qc2 and eventually e3-e4, when the c4 pawn may well be exposed.
- Simply Be2, followed by 0-0, Ne5 and f4. Or even Qc2/Qb1 and e3-e4 again.
- b3, followed by a4 whenever Black plays ...b5.
All of them should be good against a committal move like c4. I would probably play Be2, although all these choices are interesting.
OMG better trust an IM! Thank you for the tips!
Actually it's Black the one who commits to ...c4, but other than that, be my guest.