Chess openings

60 opening families, 53,097 positions, every one of them counted from real games. Each card shows the position it reaches, so you can find the opening you already play, or the one you keep running into, without knowing its name. Or analyse your own games free and find out which of them is actually working for you.

Sicilian DefenseECO A03–C21 · 9,095 positions English OpeningECO A10–B20 · 5,064 positions French DefenseECO C00–C19 · 3,066 positions King's Indian DefenseECO A15–E99 · 3,012 positions Queen's Gambit DeclinedECO A13–E00 · 2,910 positions Ruy López OpeningECO C60–C99 · 2,757 positions Caro-Kann DefenseECO A40–B19 · 1,860 positions Slav DefenseECO B12–D31 · 1,684 positions Nimzo-Indian DefenseECO E20–E58 · 1,586 positions Indian GameECO A15–E10 · 1,433 positions Queen's Pawn OpeningECO A04–E00 · 1,285 positions Alapin Sicilian DefenseECO B22 · 1,117 positions Queen's Indian DefenseECO E12–E19 · 1,031 positions Réti OpeningECO A01–E60 · 1,018 positions Grünfeld DefenseECO D70–D99 · 1,006 positions Closed Sicilian DefenseECO B23–B30 · 859 positions Pirc DefenseECO B06–C00 · 846 positions Modern DefenseECO A04–D05 · 825 positions Semi-Slav DefenseECO D02–D49 · 737 positions Queen's Gambit AcceptedECO D02–D29 · 731 positions Benko Gambit DeclinedECO A57 · 74 positions Benko Gambit Fully-AcceptedECO A58–A59 · 197 positions Benko Gambit Half-AcceptedECO A57–A58 · 185 positions Modern Defense with 1.d4ECO A40–D05 · 79 positions Benoni DefenseECO A40–E10 · 730 positions King's Indian AttackECO A07–A08 · 641 positions Dutch DefenseECO A40–A99 · 639 positions Alekhine's DefenseECO B02–B05 · 591 positions Giuoco Piano GameECO C50–C54 · 591 positions Catalan OpeningECO E00–E09 · 561 positions Scotch GameECO C44–C56 · 519 positions Scandinavian DefenseECO B01 · 519 positions Petrov's DefenseECO C42–C43 · 423 positions Bogo-Indian DefenseECO E11 · 415 positions Four Knights GameECO C47–C49 · 378 positions Philidor DefenseECO B07–C41 · 358 positions Trompowsky AttackECO A45 · 357 positions Italian GameECO C50–C59 · 332 positions Tarrasch DefenseECO D32–D40 · 321 positions King's Gambit AcceptedECO C30–C39 · 303 positions Torre AttackECO A46–A48 · 273 positions Old Indian DefenseECO A53–A55 · 247 positions King's Pawn OpeningECO A40–C44 · 235 positions Bird's OpeningECO A02–A03 · 219 positions Vienna GameECO C23–C29 · 198 positions Bishop's OpeningECO C20–C28 · 194 positions Nimzowitsch-Larsen AttackECO A00–A01 · 171 positions Old Benoni DefenseECO A43–A56 · 166 positions London SystemECO D02 · 135 positions King's Fianchetto OpeningECO A00 · 125 positions Neo-Grünfeld DefenseECO D70–E60 · 125 positions Budapest GambitECO A51–A52 · 124 positions King's Gambit DeclinedECO C30–C32 · 111 positions Semi-Slav Defense AcceptedECO D43–D44 · 107 positions Van Geet OpeningECO A00 · 103 positions Polish OpeningECO A00–A04 · 101 positions Colle SystemECO D04–D05 · 97 positions Richter-Veresov AttackECO D00–D01 · 80 positions Nimzowitsch DefenseECO B00–B01 · 76 positions Owen's DefenseECO B00 · 75 positions

Where the games actually go

Our book holds 2,874,029 games. White opens 1.e4 in 45.6% of them and 1.d4 in 35.8%, which is 81.4% between just those two moves. Whatever you end up playing, most of the positions you meet come from one of them.

White’s first move · 2,874,029 games

e445.6%

d435.8%

Nf310.2%

c46.9%

g30.7%

The rest is a long tail. 1.Nf3 and 1.c4 are real openings with real theory behind them, but together they are 17.1% of what gets played, and both often transpose back into a 1.d4 position anyway.

Two answers cover most of your games

Against 1.e4, four replies account for 90% of everything Black plays. Against 1.d4, two replies account for 87%. So a repertoire is not every opening in this index. It is one answer to 1.e4 and one to 1.d4, and then the patience to learn what happens after them.

Answers to 1.e4 · 1,300,638 games

c546.2%

e524.2%

e611.8%

c68.2%

Answers to 1.d4 · 1,026,152 games

Nf661.1%

d525.9%

e64.1%

f52.8%

The choice changes the kind of game, not the odds

The score barely moves between them. White takes 32% with 1.e4 and 32% with 1.d4, and every reply in the charts above sits within a few points of the same result. What does move is the shape of the game. 1…e5 is drawn 51% of the time against 43% for the Sicilian: the same opening move, 8 points of difference in how often the game ends level.

That is the honest way to choose one. Not which opening wins more, because none of them meaningfully does at the level these games were played, but which kind of position you want to spend your chess in, and then how much theory you are willing to carry to keep getting it.