ECO A40
ECO A00–A99 — Flank openings: 1.c4, 1.Nf3, 1.f4 and other first moves, plus early Indian and Benoni systems.
51 named opening lines are classified under ECO code A40.
- Australian Defense — 1.d4 Na6
- Benoni Defense: Franco-Sicilian Hybrid — 1.d4 e6 2.c4 c5 3.d5 exd5 4.cxd5 d6 5.Nc3 g6 6.e4 Bg7 7.Nf3 Ne7
- Borg Defense: Borg Gambit — 1.d4 g5
- Colle System: Pterodactyl Variation — 1.d4 g6 2.Nf3 Bg7 3.e3 c5 4.Bd3 Qa5+
- Colle System: Siroccopteryx Variation — 1.d4 g6 2.Nf3 Bg7 3.e3 c5 4.Bd3 cxd4 5.Nxd4 Qa5+
- English Defense — 1.d4 b6
- English Defense: Eastbourne Gambit — 1.d4 b6 2.c4 Bb7 3.Nc3 e5
- English Defense: Hartlaub Gambit Accepted — 1.c4 e6 2.d4 b6 3.Nc3 Bb7 4.e4 f5 5.exf5 Nf6
- English Defense: Hartlaub Gambit Declined — 1.c4 e6 2.d4 b6 3.Nc3 Bb7 4.e4 f5 5.d5
- English Defense: Perrin Variation — 1.d4 e6 2.c4 b6 3.e4 Bb7 4.Bd3 Nc6
- English Defense: Poli Gambit — 1.d4 e6 2.c4 b6 3.e4 Bb7 4.f3 f5 5.exf5 Nh6
- Englund Gambit — 1.d4 e5
- Englund Gambit Declined — 1.d4 e5 2.d5
- Englund Gambit Declined: Diemer Counterattack — 1.d4 e5 2.d5 Bc5 3.e4 Qh4
- Englund Gambit Declined: Reversed Alekhine — 1.d4 e5 2.Nf3
- Englund Gambit Declined: Reversed Brooklyn — 1.d4 e5 2.Nf3 e4 3.Ng1
- Englund Gambit Declined: Reversed French — 1.d4 e5 2.e3
- Englund Gambit Declined: Reversed Krebs — 1.d4 e5 2.Nf3 e4
- Englund Gambit Declined: Reversed Mokele Mbembe — 1.d4 e5 2.Nf3 e4 3.Ne5
- Englund Gambit: Felbecker Gambit — 1.d4 e5 2.dxe5 Nc6 3.Nf3 Bc5
- Englund Gambit: Hartlaub-Charlick Gambit — 1.d4 e5 2.dxe5 d6
- Englund Gambit: Main Line — 1.d4 e5 2.dxe5 Nc6 3.Nf3 Qe7
- Englund Gambit: Mosquito Gambit — 1.d4 e5 2.dxe5 Qh4
- Englund Gambit: Soller Gambit — 1.d4 e5 2.dxe5 f6
- Englund Gambit: Soller Gambit Deferred — 1.d4 e5 2.dxe5 Nc6 3.Nf3 f6
- Englund Gambit: Stockholm Variation — 1.d4 e5 2.dxe5 Nc6 3.Nf3 Qe7 4.Qd5
- Englund Gambit: Zilbermints Gambit — 1.d4 e5 2.dxe5 Nc6 3.Nf3 Nge7
- Horwitz Defense — 1.d4 e6
- Horwitz Defense: Zilbermints Gambit — 1.d4 e6 2.c4 e5
- Kangaroo Defense — 1.d4 e6 2.c4 Bb4+
- Kangaroo Defense: Keres Defense, Transpositional Variation — 1.d4 e6 2.c4 Bb4+ 3.Nc3
- Mikenas Defense — 1.d4 Nc6
- Mikenas Defense: Cannstatter Variation — 1.d4 Nc6 2.c4 e5 3.d5 Nd4
- Mikenas Defense: Lithuanian Variation — 1.d4 Nc6 2.c4 e5 3.d5 Nce7
- Mikenas Defense: Pozarek Gambit — 1.d4 Nc6 2.c4 e5 3.dxe5 Nxe5 4.Nc3 Nxc4
- Modern Defense: Beefeater Variation — 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.d5 Bxc3+ 5.bxc3 f5
- Modern Defense: Lizard Defense, Pirc-Diemer Gambit — 1.d4 g6 2.h4 Nf6 3.h5
- Montevideo Defense — 1.d4 Nc6 2.d5 Nb8
- Polish Defense — 1.d4 b5
- Polish Defense: Spassky Gambit Accepted — 1.d4 b5 2.e4 Bb7 3.Bxb5
- Pterodactyl Defense: Central, Benoni Beefeater Pterodactyl — 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.d5 d6 5.e4 Bxc3+ 6.bxc3 Qa5
- Pterodactyl Defense: Central, Benoni Pterodactyl — 1.d4 g6 2.c4 Bg7 3.e4 c5 4.d5 Qa5+
- Pterodactyl Defense: Fianchetto, Queen Benoni Pterodactyl — 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.d5 Qa5
- Pterodactyl Defense: Fianchetto, Queen Pteranodon — 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.d5 Bxc3+ 5.bxc3 Qa5
- Pterodactyl Defense: Fianchetto, Queen Pterodactyl — 1.d4 g6 2.Nf3 Bg7 3.g3 c5 4.Bg2 Qa5+
- Pterodactyl Defense: Queen Pterodactyl, Quiet Line — 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.e3
- Queen's Pawn Game — 1.d4
- Queen's Pawn Game: Anglo-Slav Opening — 1.d4 c6 2.c4 d6
- Queen's Pawn Game: Modern Defense — 1.d4 g6
- Slav Indian: Kudischewitsch Gambit — 1.d4 c6 2.Nf3 Nf6 3.c4 b5
- Zaire Defense — 1.d4 Nc6 2.d5 Nb8 3.e4 Nf6 4.e5 Ng8