Attack before the doubled pawn becomes decisive

Compare the capture with keeping tension

White's d4-pawn and Black's c5-pawn attack each other geometrically. Compare the recaptures and newly opened lines before exchanging; the contact alone does not prove that either capture is legal or good.

Identify the chain's support

White's pawn chain on c3, d4 has c3 at its base. Test whether pressure on that support changes the advanced pawns' stability; piece placement and tactics determine whether a break works.