Queen's Gambit Declined: Been-Koomen Variation
Variations
Queen's Gambit Declined: Pseudo-Tarrasch Variation, Primitive Pillsbury Variation
5. Nf3 cxd4 6. Qxd4
Queen's Gambit Declined: Semi-Tarrasch Defense, Krause Variation
5. Nf3 cxd4 6. Nxd4 e5 7. Ndb5 a6 8. Qa4