Queen's Gambit Declined: Mighty Minority Attack

The Minority Attack

White pushes b2-b4-b5, threatening bxc6. If Black permits this capture by responding ... bxc6, he leaves the c6 pawn backward and vulnerable on the
half open c-file. If he tries to stop b4-b5 through ... b5, the c6 pawn is
still weakened, unless he can block the c-file by sinking a piece into c4.
The third possibility, which entails exchanging the menacing b5 pawn via
... cxb5, is perhaps the least satisfactory one. His d-pawn becomes
isolated and, after White recaptures on b5 with a minor piece, the b7
pawn turns into a target on the b-file. Black's best hope against the
Minority Attack is in launching a kingside offensive. However, even
against such an active response, White's queenside hostilities usually
abide.