ECO D21
ECO D00–D99 — Closed and Semi-Closed Games: 1.d4 d5 queen's pawn openings and the Grünfeld Defense.
6 named opening lines are classified under ECO code D21.
- Queen's Gambit Accepted: Alekhine Defense, Borisenko-Furman Variation — 1.d4 d5 2.c4 dxc4 3.Nf3 a6 4.e4
- Queen's Gambit Accepted: Godes Variation — 1.d4 d5 2.c4 dxc4 3.Nf3 Nd7
- Queen's Gambit Accepted: Gunsberg Defense — 1.d4 d5 2.c4 dxc4 3.Nf3 c5
- Queen's Gambit Accepted: Normal Variation — 1.d4 d5 2.c4 dxc4 3.Nf3
- Queen's Gambit Accepted: Rosenthal Variation — 1.d4 d5 2.c4 dxc4 3.Nf3 e6
- Queen's Gambit Accepted: Slav Gambit — 1.d4 d5 2.c4 dxc4 3.Nf3 b5