ECO D20
ECO D00–D99 — Closed and Semi-Closed Games: 1.d4 d5 queen's pawn openings and the Grünfeld Defense.
17 named opening lines are classified under ECO code D20.
- Queen's Gambit Accepted — 1.d4 d5 2.c4 dxc4
- Queen's Gambit Accepted: Accelerated Mannheim Variation — 1.d4 d5 2.c4 dxc4 3.Qa4+
- Queen's Gambit Accepted: Central Variation, Alekhine System — 1.d4 d5 2.c4 dxc4 3.e4 Nf6
- Queen's Gambit Accepted: Central Variation, Greco Variation — 1.d4 d5 2.c4 dxc4 3.e4 b5
- Queen's Gambit Accepted: Central Variation, McDonnell Defense — 1.d4 d5 2.c4 dxc4 3.e4 e5
- Queen's Gambit Accepted: Central Variation, McDonnell Defense, Somov Gambit — 1.d4 d5 2.c4 dxc4 3.e4 e5 4.Bxc4
- Queen's Gambit Accepted: Central Variation, Modern Defense — 1.d4 d5 2.c4 dxc4 3.e4 Nc6
- Queen's Gambit Accepted: Central Variation, Rubinstein Defense — 1.d4 d5 2.c4 dxc4 3.e4 c5
- Queen's Gambit Accepted: Central Variation, Rubinstein Defense, Yefimov Gambit — 1.d4 d5 2.c4 dxc4 3.e4 c5 4.d5 b5
- Queen's Gambit Accepted: Linares Variation — 1.d4 d5 2.c4 dxc4 3.e4 c5 4.d5 Nf6 5.Nc3 b5
- Queen's Gambit Accepted: Old Variation — 1.d4 d5 2.c4 dxc4 3.e3
- Queen's Gambit Accepted: Old Variation, Billinger Gambit — 1.d4 d5 2.c4 dxc4 3.e3 e5 4.Bxc4 exd4 5.Qb3 Qe7 6.a3
- Queen's Gambit Accepted: Old Variation, Christensen Gambit — 1.d4 d5 2.c4 dxc4 3.e3 e5 4.Bxc4 exd4 5.Qb3 Qe7 6.Nf3
- Queen's Gambit Accepted: Old Variation, Korchnoi Gambit — 1.d4 d5 2.c4 dxc4 3.e3 e5 4.Bxc4 exd4 5.Qb3 Qe7 6.Kf1
- Queen's Gambit Accepted: Old Variation, Novikov Gambit — 1.d4 d5 2.c4 dxc4 3.e3 e5 4.Bxc4 exd4 5.Qb3 Qe7 6.Nd2
- Queen's Gambit Accepted: Saduleto Variation — 1.d4 d5 2.c4 dxc4 3.e4
- Queen's Gambit Accepted: Schwartz Defense — 1.d4 d5 2.c4 dxc4 3.e4 f5