Meeting 1.d4: The QGD Setup

Against 1.d4, your answer is the Queen's Gambit Declined setup: ...d5, ...e6, ...Nf6, ...Be7, castle. Five moves, playable against almost anything White tries.

The logic: ...d5 stakes the center; ...e6 REINFORCES d5 before White's c4 can drag it away; then develop and castle. It's the Italian principle — center, develop, castle — wearing a different shirt.