text: This is a list of chess openings, organised by the Encyclopaedia of Chess Openings (ECO) code classification system. The chess openings are categorised into five broad areas ("A" through "E"), with each of those broken up into one hundred subcategories ("00" through "99"). The openings were published in five volumes of ECO, with volumes labeled "A" through "E".
  A – Flank openings
  White first moves other than 1.e4, 1.d4 (A00–A39)
  1.d4 without 1...d5, 1...Nf6 or 1...f5: Atypical replies to 1.d4 (A40–A44)
  1.d4 Nf6 without 2.c4: Atypical replies to 1...Nf6 (A45–A49)
  1.d4 Nf6 2.c4 without 2...e6 or 2...g6: Atypical Indian systems (A50–A79)
  1.d4 f5: Dutch Defence (A80–A99)
  A00–A09
  White first moves other than 1.e4, 1.d4, 1.c4:
  A00 Irregular Openings
  Anderssen Opening: 1.a3
  Anderssen Opening, Polish Gambit: 1...a5 2.b4
  Anderssen Opening, Bugayev Attack: 1...e5 2.b4
  Anderssen Opening, Creepy Crawly Formation: 1...e5 2.h3 d5
  Anderssen Opening, Andersspike: 1...g6 2.g4
  Anderssen Opening, Sammarinese Gambit: 1...a6
  Ware Opening: 1.a4
  Ware Opening, Cologne Gambit: 1...b6 2.d4 d5 3.Nc3 Nd7
  Ware Opening, Wing Gambit: 1...b5 2.axb5 Bb7
  Ware Opening, Ware Gambit: 1...e5 2.a5 d5 3.e3 f5 4.a6
  Ware Opening, Crab Variation: 1...e5 2.h4
  Sodium Attack: 1.Na3
  Sodium Attack, Celadon Variation: 1...e5 2.d3 Bxa3 3.bxa3 d5 4.e3 c5 5.Rb1