# ECO index: A00--A99

    A00: Uncommon Openings: 1. g3 (Benko Opening), 1. Nc3 (Sleipner Opening), 1. a3 (Anderssen's Opening), 1. b4 (Polish Opening), 1. g4 (Grob's Attack), 1. h3 (Basmanic Defence), 1. c3 (Saragossa Opening), 1. d3 (Mieses Opening), 1. e3 (French Attack), 1. h4 (Desprez Opening), 1. a4 (Ware Opening), 1. Nh3 (Amar Opening), 1. Na3 (Durkin's Attack), 1. f3 (Gedult's Opening), 1. e3 e5 2. e4 (King's Isa Reverse)
    A01: Nimzowitsch-Larsen Attack: 1. b3
    A02: Bird's Opening: 1. f4
    A03: Bird's Opening: 1. f4 d5
    A04: Reti Opening: 1. Nf3
    A05: Reti Opening: 1. Nf3 Nf6
    A06: Reti Opening: 1. Nf3 d5
    A07: King's Indian Attack: 1. Nf3 d5 2. g3
    A08: King's Indian Attack: 1. Nf3 d5 2. g3 c5 3. Bg2
    A09: Reti Opening: 1. Nf3 d5 2. c4
    A10: English: 1. c4
    A11: English, Anglo-Slav System: 1. c4 c6
    A12: English with b3: 1. c4 c6 2. Nf3 d5 3. b3
    A13: English: 1. c4 e6
    A14: English: 1. c4 e6 2. Nf3 d5 3. g3 Nf6 4. Bg2 Be7 5. O-O
    A15: English: 1. c4 Nf6
    A16: English: 1. c4 Nf6 2. Nc3
    A17: English: 1. c4 Nf6 2. Nc3 e6
    A18: English, Mikenas-Carls: 1. c4 Nf6 2. Nc3 e6 3. e4
    A19: English, Mikenas-Carls, Sicilian Variation: 1. c4 Nf6 2. Nc3 e6 3. e4 c5
    A20: English: 1. c4 e5
    A21: English: 1. c4 e5 2. Nc3
    A22: English: 1. c4 e5 2. Nc3 Nf6
    A23: English, Bremen System, Keres Variation: 1. c4 e5 2. Nc3 Nf6 3. g3 c6
    A24: English, Bremen System with ...g6: 1. c4 e5 2. Nc3 Nf6 3. g3 g6
    A25: English: 1. c4 e5 2. Nc3 Nc6
    A26: English: 1. c4 e5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. d3 d6
    A27: English, Three Knights System: 1. c4 e5 2. Nc3 Nc6 3. Nf3
    A28: English: 1. c4 e5 2. Nc3 Nc6 3. Nf3 Nf6
    A29: English, Four Knights, Kingside Fianchetto: 1. c4 e5 2. Nc3 Nc6 3. Nf3 Nf6 g3
    A30: English, Symmetrical: 1. c4 c5
    A31: English, Symmetrical, Benoni Formation: 1. c4 c5 2. Nf3 Nf6 3. d4
    A32: English, Symmetrical Variation: 1. c4 c5 2. Nf3 Nf6 3. d4 cxd4 4. Nxd4 e6
    A33: English, Symmetrical: 1. c4 c5 2. Nf3 Nf6 3. d4 cxd4 4. Nxd4 e6 5. Nc3 Nc6
    A34: English, Symmetrical: 1. c4 c5 2. Nc3
    A35: English, Symmetrical: 1. c4 c5 2. Nc3 Nc6
    A36: English, Symmetrical: 1. c4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7
    A37: English, Symmetrical: 1. c4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. Nf3
    A38: English, Symmetrical: 1. c4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. Nf3 Nf6
    A39: English, Symmetrical: 1. c4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. Nf3 Nf6 6. O-O O-O 7. d4
    A40: Unusual Black responses to 1. d4: 1...e5 (Englund Gambit), 1...b5 (Polish Defence), 1...Nc6 (Nimzowitsch Defence), 1...g6 (Modern Defence without 2. e4), 1...e6 (French Indian Defence).
    A41: Tartakower System: 1. d4 d6
    A42: Tartakower System with 2. c4: 1. d4 d6 2.c4
    A43: Various Benonis: 1. d4 c5
    A44: Old Benoni: 1. d4 c5 2. d5 e5
    A44: Semi-Benoni: 1. d4 c5 2. d5 e5 3. e4 d6
    A45: Unusual Indian Openings: 1. d4 Nf6
    A45: Trompowsky Attack: 1. d4 Nf6 2. Bg5
    A46: Unusual Indian Openings with 2. Nf3: 1. d4 Nf6 2. Nf3
    A47: Unusual Indian Openings with 2. Nf3: 1. d4 Nf6 2. Nf3 b6
    A48: Torre Attack with 2...e6: 1. d4 Nf6 2. Nf3 e6 3. Bg5
    A48: Torre Attack with 2...g6: 1. d4 Nf6 2. Nf3 g6 3. Bg5
    A48: London System: 1. d4 Nf6 2. Nf3 e6 3. Bf4
    A49: Fianchetto Variation: 1. d4 Nf6 2. Nf3 e6 3. g3
    A50: Black Knights' Tango: 1. d4 Nf6 2. c4 Nc6
    A51: Budapest Gambit Declined and Unusual Lines: 1. d4 Nf6 2. c4 e5
    A52: Budapest Gambit Main Lines: 1. d4 Nf6 2. c4 e5 3. dxe5 Ng4
    A53: Old Indian Defence: 1. d4 Nf6 2. c4 d6
    A54: Old Indian Defence main lines: 1. d4 Nf6 2. c4 d6 3. Nc3 e5
    A55: Old Indian Defence main lines: 1. d4 Nf6 2. c4 d6 3. Nc3 e5 4. Nf3
    A56: Czech Benoni: 1. d4 Nf6 2. c4 c5 3. d5
    A57: Benko/Volga Gambit sidelines: 1. d4 Nf6 2. c4 c5 3. d5 b5
    A58: Benko/Volga Gambit Accepted: 1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5
    A59: Benko/Volga Gambit Accepted (White castles by hand): 1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5 a6 5. bxa6 Bxa6 6. Nc3 d6 7. e4
    A60: Modern Benoni and early divergences: 1. d4 Nf6 2. c4 c5 3. d5 e6
    A61: Modern Benoni without early e4: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6
    A62: Modern Benoni, Fianchetto Variation without early ...Nbd7: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3 g6 7. g3
    A63: Modern Benoni, Fianchetto Variation sidelines: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3 g6 7. g3 Bg7 8. Bg2 O-O
    A64: Modern Benoni, Fianchetto Variation main line: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3 g6 7. g3 Bg7 8. Bg2 O-O 9. O-O Re8 10. Nd2 Nbd7
    A65: Modern Benoni, sidelines with early e4: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4
    A66: Modern Benoni, Mikenas Attack: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. f4 Bg7 8. e5
    A67: Modern Benoni, Taimanov Variation: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. f4 Bg7 8. Bb5+
    A68: Modern Benoni, Four Pawns Attack without 9...Re8: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. f4 Bg7 8. Nf3 O-O 9. Bd3
    A69: Modern Benoni, Four Pawns Attack with 9...Re8: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. f4 Bg7 8. Nf3 O-O 9. Re8
    A70: Modern Benoni, 7.Nf3: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3
    A71: Modern Benoni, 7.Nf3 Bg7 8.Bg5 without Be2: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Bg5
    A72: Modern Benoni, Classical Variation with Bg5: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. Bg5
    A73: Modern Benoni, Classical Variation and unusual Black 9th moves: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O
    A74: Modern Benoni, Classical Variation with 9...a6: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O a6
    A75: Modern Benoni, Classical Variation main line: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O a6 10. a4 Bg4
    A76: Modern Benoni, Classical Variation with 9...Re8 10.Qc2: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O Re8 10. Qc2
    A77: Modern Benoni, Classical Variation with 9...Re8 10.Nd2: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O Re8 10. Nd2
    A78: Modern Benoni, Classical Variation with 10...Na6: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O Re8 10. Nd2 Na6
    A79: Modern Benoni, Classical Variation with 10...Na6 11.f3: 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O Re8 10. Nd2 Na6 11. f3
    A80: Dutch Defence and unusual White second moves: 1. d4 f5
    A81: Dutch Defence with 2.g3: 1. d4 f5 2. g3
    A82: Dutch Defence, Staunton Gambit: 1. d4 f5 2. e4
    A83: Dutch Defence, Staunton Gambit with 3.Nc3 Nf6 4.Bg5: 1. d4 f5 2. e4 fxe4 3. Nc3 Nf6 4. Bg5
    A84: Dutch Defence, 2.c4: 1. d4 f5 2. c4
    A85: Dutch Defence, 2.c4 Nf6 3.Nc3: 1. d4 f5 2. c4 Nf6 3. Nc3
    A86: Dutch Defence, Leningrad Variation sidelines: 1. d4 f5 2. c4 Nf6 3. g3
    A87: Dutch Defence, Leningrad Variation with 5.Nf3: 1. d4 f5 2. c4 Nf6 3. g3 g6 4. Bg2 Bg7 5. Nf3
    A88: Dutch Defence, Leningrad Variation main line 7...c6: 1. d4 f5 2. c4 Nf6 3. g3 g6 4. Bg2 Bg7 5. Nf3 O-O 6. O-O d6 7. Nc3 c6
    A89: Dutch Defence, Leningrad Variation main line 7...Nc6: 1. d4 f5 2. c4 Nf6 3. g3 g6 4. Bg2 Bg7 5. Nf3 O-O 6. O-O d6 7. Nc3 Nc6
    A90: Dutch Defence sidelines and Stonewall: 1. d4 f5 2. c4 Nf6 3. g3 e6
    A91: Dutch Defence, Classical Variation sidelines: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7
    A92: Dutch Defence, Classical Stonewall with ...Be7 and early deviations: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3
    A93: Dutch Defence, Classical Stonewall with 7.b3: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 d5 6. O-O O-O 7. b3
    A94: Dutch Defence, Classical Stonewall with 7.b3 c6 8.Ba3: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 d5 6. O-O O-O 7. b3 c6 8. Ba3
    A95: Dutch Defence, Classical Stonewall with 7.Nc3 c6: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 d5 6. O-O O-O 7. Nc3 c6
    A96: Dutch Defence, Ilyin-Genevsky Variation: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 O-O 6. O-O d6
    A97: Dutch Defence, Ilyin-Genevsky Variation: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 O-O 6. O-O d6 7. Nc3 Qe8
    A98: Dutch Defence, Ilyin-Genevsky Variation with 8.Qc2: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 O-O 6. O-O d6 7. Nc3 Qe8 8. Qc2
    A99: Dutch Defence, Ilyin-Genevsky Variation with 8.b3: 1. d4 f5 2. c4 Nf6 3. g3 e6 4. Bg2 Be7 5. Nf3 O-O 6. O-O d6 7. Nc3 Qe8 8. b3

## ECO volumes

    ECO volume A A00-A99
    ECO volume B B00-B99
    ECO volume C C00-C99
    ECO volume D D00-D99
    ECO volume E E00-E99

## External Links

Chess Archaeology: Openings classified ECO A00-A99 from chessarch.com