ECO C31
ECO C00–C99 — Open Games and the French Defense: 1.e4 e6 and 1.e4 e5, from the Italian and Ruy Lopez to the King's Gambit.
15 named opening lines are classified under ECO code C31.
- King's Gambit Declined: Falkbeer Countergambit — 1.e4 e5 2.f4 d5
- King's Gambit Declined: Falkbeer Countergambit Accepted — 1.e4 e5 2.f4 d5 3.exd5
- King's Gambit Declined: Falkbeer Countergambit, Anderssen Attack — 1.e4 e5 2.f4 d5 3.exd5 e4 4.Bb5+
- King's Gambit Declined: Falkbeer Countergambit, Blackburne Attack — 1.e4 e5 2.f4 d5 3.Nf3
- King's Gambit Declined: Falkbeer Countergambit, Charousek Gambit — 1.e4 e5 2.f4 d5 3.exd5 e4 4.d3
- King's Gambit Declined: Falkbeer Countergambit, Charousek Gambit, Morphy Defense — 1.e4 e5 2.Nc3 Nf6 3.f4 d5 4.exd5 e4 5.d3 Bb4 6.Bd2 e3
- King's Gambit Declined: Falkbeer Countergambit, Hinrichsen Gambit — 1.e4 e5 2.f4 d5 3.d4
- King's Gambit Declined: Falkbeer Countergambit, Miles Gambit — 1.e4 e5 2.f4 d5 3.exd5 Bc5
- King's Gambit Declined: Falkbeer Countergambit, Milner-Barry Variation — 1.e4 e5 2.f4 d5 3.Nc3
- King's Gambit Declined: Falkbeer Countergambit, Modern Transfer — 1.e4 e5 2.f4 d5 3.exd5 exf4
- King's Gambit Declined: Falkbeer Countergambit, Nimzowitsch-Marshall Countergambit — 1.e4 e5 2.f4 d5 3.exd5 c6
- King's Gambit Declined: Falkbeer Countergambit, Pickler Gambit — 1.e4 e5 2.f4 d5 3.exd5 c6 4.dxc6 Bc5
- King's Gambit Declined: Falkbeer Countergambit, Rubinstein Variation — 1.e4 e5 2.f4 d5 3.exd5 e4 4.Nc3 Nf6 5.Qe2
- King's Gambit Declined: Falkbeer Countergambit, Staunton Line — 1.e4 e5 2.f4 d5 3.exd5 e4
- Van Geet Opening: Grünfeld Defense, Steiner Gambit — 1.e4 e5 2.f4 d5 3.Nc3 dxe4 4.Nxe4