Theory
2…e6 is Black’s most solid reply to the Queen’s Gambit: it supports d5 without weakening the position the way accepting the pawn (dxc4) or the Slav’s c6 can. The trade-off is the light-squared bishop, temporarily boxed in behind the e6 pawn.
The Queen’s Gambit Declined sits in ECO’s D30–D69 range and produces some of the most thoroughly analysed middlegame structures in chess — the Carlsbad structure, the Isolated Queen Pawn, and the Minority Attack all grow directly out of QGD move orders, which is why this opening pairs so naturally with middlegame study.
Model Games
Capablanca’s QGD games remain the reference point for how to solve the light-squared bishop problem — typically via an early b6 and Bb7, or by trading it off entirely with Bb4 lines. His technique for converting small structural edges is still the clearest teaching material available.
Practice Positions
Set up the Exchange Variation structure (pawns on c3/d4 vs c6/d5 after an early cxd5 exd5) and practice identifying whether White’s minority attack (b4-b5) or Black’s central break (e5) arrives first.