About the project

Every opening. Every defence. One library.

Chess Openings is a free encyclopedia of chess openings and defences. Right now it holds 1,506 in-depth guides — covering all 500 ECO classification codes plus every named variation inside its opening systems — and each one is built around the same promise: show the moves, explain the ideas, warn about the traps, and leave you with a study plan.

500 ECO code guides

Every code from A00 to E99 has its own page: the main line, the plans for both sides, and the variations worth studying first.

Deep system guides

Major openings get full family guides — ideas for both colours, traps, famous practitioners, history and every important named branch.

Interactive boards

Every move sequence is playable: step through the moves, flip the board, copy the PGN. Understanding beats memorising — see the position, don't just read it.

Search that understands chess

Search by name, ECO code, first moves or concepts — “B90”, “dragon”, “1.e4 c5” all find exactly what you need, instantly.

Built for study, not browsing

Every guide ends with a study plan: learn the setup, then the pawn breaks, then the forcing lines — in that order.

Free, forever

No paywalls, no accounts, no ads on the board. Made for the love of the game and shared with everyone who plays it.

How to build a repertoire here

  1. 1. Pick your White foundation. Choose 1.e4 (open, fighting) or 1.d4 (closed, strategic) — or a flank system like the English. Search for it and read the family guide first.
  2. 2. Choose defences against the main threats. From the For Black collection, pick one answer each to 1.e4 and 1.d4, plus one reply to the English/Reti complex.
  3. 3. Go one move deeper. Each family page links its named variations — study those branches once the parent system feels natural.
  4. 4. Follow the study plan. Every guide ends with a three-step plan. Ideas first, breaks second, theory third — always in that order.

Chess Openings is an educational project. ECO is a classification framework; all analysis here is original and written for learning. Play beautifully.