Chess Opening Data & Elo Analysis: The Statistical Playbook

TL;DR

• All 36 openings on this site are built from Lichess games at that opening's own rating range, from about 0.9 million games (Catalan, 1400 to 2200) to about 183 million (King's Indian, 1400 to 2200). 27 of the 36 are backed by more than 10 million games.
• Every opening carries a recommended Elo range, from a 400 floor (London System, Torre Attack, Scandinavian) to an 1800 floor (Grünfeld), and move-frequency data for every opponent reply in its trainer.
• The library holds 613 practice lines, from 6 in the Danish Gambit to 23 in the Ruy Lopez Closed. Every one of your moves is checked by Stockfish; your opponent's moves are the most common replies at that level.
• Some openings now include results where our data states them, for example "White wins 53% of games after 2.f4" in the King's Gambit at 900 to 2200 on Lichess. We quote those exactly, always with the rating band, and never compute our own.

What "Data-Driven" Actually Means Here

Most opening advice online is a strong player's opinion, dressed up as a rule. "Always play this," "never play that", stated with confidence, backed by nothing you could check yourself.

This site takes a different approach: every opening is built from what players at its recommended rating range actually play on Lichess, millions of games per opening in most cases. The opponent moves in each trainer are the most common replies at that level, and your own moves are checked by Stockfish. That gives four different kinds of data, and this hub is about being precise regarding which one applies where:

1. Recommended Elo range. Each of the 36 openings has a suitability range based on how sharp the resulting positions are and how much precise calculation they demand. The lowest floor is 400 and the highest is 1800. A beginner-friendly system and a razor-sharp gambit aren't suited to the same player, even if both are sound. The Italian Game, for example, is now recommended from 1000 to 1600.

2. Move frequency. At any given position, this data shows what share of games at that rating range played each move. After 1.d4 d5 2.Bf4, for example, 400 to 1400 rated players answer 2...Nc6 in 37% of games and 2...Nf6 in 20%. A reply played in 70% of games is close to forced; one played in 12% is a live decision point.

3. Game volume. How many Lichess games at the opening's rating range stand behind each repertoire. Because some repertoires share early positions (the Italian and the Scotch both start 1.e4 e5 2.Nf3), we report each opening's count on its own and don't add them into one inflated total.

4. Results, where stated. Some guides now quote how often a side wins after a specific move at that level, such as "White wins 72% of games after 5.Qe2" against 4...Qe7 in the Vienna Gambit at 800 to 1800. These come straight from the data files, word for word, with the rating band. We never compute or estimate a win rate ourselves.

The Articles in This Series

Which White Openings Are Right for 1200 to 1500 Elo

Five White openings whose recommended range fully covers the 1200 to 1500 band, with Lichess game counts and move-frequency data for each one's key lines.

The Most Reliable 1.e4 Defenses for Black

Every 1.e4 defense on this site, verified directly from each opening's actual first move, not assumed from its name.

Why the Sicilian Najdorf Isn't Recommended Under 1500 Elo

A look at what makes the Najdorf demanding below 1600: three separate points where White picks between five or more common systems, more than any other 1.e4 defense in our library.

Keep reading

More from this part of the site:

• Best Chess Openings for Beginners: Our full list of openings grouped by rating.

Start With the Real Data Yourself

Every opening referenced across this series is fully interactive on this site, with lines built from the same Lichess data cited above and move-by-move coaching. All 36 openings are completely unlocked during this site's open beta, no card, no limit, no account required to start, with your progress tracked for free if you create one.

Explore all 36 openings →