ECO D50
6 named openings and variations are classified as D50. ECO (Encyclopaedia of Chess Openings) codes group openings from A00 to E99 by their opening moves.
- Queen's Gambit Declined: Been-Koomen VariationD501. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 c5
- Queen's Gambit Declined: Modern VariationD501. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5
- Queen's Gambit Declined: Pseudo-Tarrasch VariationD501. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 c5 5. cxd5
- Queen's Gambit Declined: Pseudo-Tarrasch Variation, Canal VariationD501. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 c5 5. cxd5 Qb6
- Queen's Gambit Declined: Pseudo-Tarrasch Variation, Primitive Pillsbury VariationD501. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 c5 5. Nf3 cxd4 6. Qxd4
- Queen's Gambit Declined: Semi-Tarrasch Defense, Krause VariationD501. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 c5 5. Nf3 cxd4 6. Nxd4 e5 7. Ndb5 a6 8. Qa4