ECO D21
6 named openings and variations are classified as D21. ECO (Encyclopaedia of Chess Openings) codes group openings from A00 to E99 by their opening moves.
- Queen's Gambit Accepted: Alekhine Defense, Borisenko-Furman VariationD211. d4 d5 2. c4 dxc4 3. Nf3 a6 4. e4
- Queen's Gambit Accepted: Godes VariationD211. d4 d5 2. c4 dxc4 3. Nf3 Nd7
- Queen's Gambit Accepted: Gunsberg DefenseD211. d4 d5 2. c4 dxc4 3. Nf3 c5
- Queen's Gambit Accepted: Normal VariationD211. d4 d5 2. c4 dxc4 3. Nf3
- Queen's Gambit Accepted: Rosenthal VariationD211. d4 d5 2. c4 dxc4 3. Nf3 e6
- Queen's Gambit Accepted: Slav GambitD211. d4 d5 2. c4 dxc4 3. Nf3 b5