Chess by the numbers
How many chess openings are there?
There is no single number, because an opening is a name people give to a sequence of moves. The Encyclopaedia of Chess Openings sorts them into 500 codes, A00 to E99. The open Lichess list names 3,865 lines; with five of its own, this site knows 3,870 named positions.
500 ECO codes in five volumes
The ECO system, published by the Yugoslav Chess Informant, divides the openings into five volumes of a hundred codes each. Here is how the 3,870 named positions on this site fall into them:
| Volume | Mostly | Named lines |
|---|---|---|
| A | flank openings, 1. d4 without 1... d5, the English | 826 |
| B | 1. e4 without 1... e5 or 1... e6: Sicilian, Caro-Kann, Pirc… | 781 |
| C | 1. e4 e5 and the French Defense | 1,251 |
| D | 1. d4 d5: the Queen’s Gambit, the Slav, the Grünfeld | 644 |
| E | the Indian defences: Nimzo-Indian, Queen’s Indian, King’s Indian | 368 |
Names, not openings
Many names come back on several lines — “Sicilian Defense: Najdorf Variation” names the position after 5... a6 and several deeper ones — so the 3,870 named positions carry 3,178 different names. Some families are far richer than others:
| Family | Named lines |
|---|---|
| Sicilian Defense | 400 |
| Ruy Lopez | 235 |
| French Defense | 212 |
| Queen's Gambit Declined | 211 |
| Italian Game | 187 |
| English Opening | 176 |
| King's Gambit Accepted | 137 |
| King's Indian Defense | 120 |
Where the names stop
The deepest named line on the list is 36 moves long: 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. c3 d5 9. exd5 Nxd5 10. Nxe5 Nxe5 11. Rxe5 c6 12. d4 Bd6 13. Re1 Qh4 14. g3 Qh3 15. Be3 Bg4 16. Qd3 Rae8 17. Nd2 Re6 18. a4 Qh5 (Ruy Lopez: Marshall Attack, Main Line, Spassky Variation). Most lines are much shorter, and every game soon leaves the named roads; on the map the move where that happens is marked. The openings index has a page for each of the best-known ones, and the opening map colours every move by the names it leads to.