ECO D51

ECO D00–D99 — Closed and Semi-Closed Games: 1.d4 d5 queen's pawn openings and the Grünfeld Defense.

5 named opening lines are classified under ECO code D51.

• Queen's Gambit Declined: Alekhine Variation — 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Nbd7 5.Nf3 c6 6.e4
• Queen's Gambit Declined: Capablanca Variation, Anti-Cambridge Springs Variation — 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Nbd7 5.e3 c6 6.a3
• Queen's Gambit Declined: Manhattan Variation — 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Nbd7 5.e3 Bb4
• Queen's Gambit Declined: Modern Variation, Knight Defense — 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Nbd7
• Queen's Gambit Declined: Rochlin Variation — 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Nbd7 5.Nf3 c6 6.Rc1 Qa5 7.Bd2