Queen's Gambit Declined

Hold the centre with a rock-solid pawn chain and develop behind it. Played from Black.

1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Be7 5.e3 O-O 6.Nf3

Opening data: Lichess chess-openings (Queen's Gambit Declined, ECO D37) (CC0-1.0).