Frequently Asked Questions

Ochess is a free chess opening trainer built around your own games. It imports your games, builds a personalised opening repertoire from them, and helps you drill it. Alongside that you get ready-made opening courses, written opening guides, tactical puzzles, a catalogue of opening traps, and personal labs where you build and train your own move trees. Every position can be explored on a board with engine analysis and statistics from millions of rated games. It is completely free while it is in beta testing.

Yes. Ochess is completely free while it is in beta — no ads, no paywalls. If paid features are ever introduced, the tools you rely on today will stay available. See the plans page.

Yes, for the heart of Ochess: importing your games, your generated repertoire, full game analysis, personal labs and saved progress all need a free account. Opening guides, traps and puzzles are fully open without one; with courses you can preview the first section, and the rest opens once you sign up. Sign up with an email address or a Google account.

Ochess is in English.

Yes. Ochess runs in your mobile browser and the whole site is designed to work on small screens. There is no separate app to install.

Yes. When you sign up you can enter your Lichess and/or Chess.com usernames, and your recent games are pulled in automatically in the background. The download runs from your own browser, so it is fast and does not hit shared rate limits. Once imported, your games are analysed and your repertoire is built with no extra steps.

Open My Games and use the import panel to add games from Lichess, Chess.com, or by pasting PGN. New games are analysed the same way as your initial import.

Accuracy is a single 0–100% score for how closely you played to the engine's best moves in a game. It comes from Stockfish's evaluation of every move: small inaccuracies cost a little, blunders cost a lot. It is shown for each analysed game in My Games and broken down move by move in the game report.

Maia is a neural-network chess engine trained on human games, so it predicts the moves players actually make — not just the engine-perfect one. In your game analysis, Maia shows what a player at your level would typically play in each position, and flags the moves you found that are above your level. It complements Stockfish: Stockfish tells you the objectively best move, Maia tells you the human one. Maia models players from roughly 1100 to 2000, so its read on your moves is most meaningful in that range.

Three kinds: your online rating (imported from Lichess/Chess.com), a Performance rating estimated from your accuracy, and a Maia rating that estimates your playing strength and style (most meaningful roughly between 1100 and 2000). Open any game in My Games to see your Performance and Maia ratings in the analysis, and use the Progress view in My Games to chart how your rating, accuracy, Performance and Maia estimate move over time.

Stockfish, the strongest open-source engine, together with the human-like Maia engine. When you explore a position on a board, Stockfish runs directly in your browser; full game reports and repertoire building are computed on our server.

Your repertoire is a personal map of the openings you actually play, generated from your imported games. Instead of a generic "best" line, it shows the openings you reach most often, the points where your play tends to leave known theory, and a solid continuation from there — assembled by algorithms we developed specifically for this, then checked with the engine.

Ochess scans your games position by position and finds the recurring points where you drift from theory or lose the thread. For each one it builds a section: your side follows the strongest theory, while the opponent's replies are the moves players at your rating actually play most often (from millions of rated Lichess games), with the engine keeping the lines honest and showing you how to punish common mistakes. It is regenerated as you import more games.

In My Games, open the Repertoire tab. Every repertoire Ochess builds is saved there, with a short written summary of your opening habits; open one to study its lines on the board or in a lab.

Courses are ready-made opening repertoires, built by algorithms we developed — one for each of a range of popular openings — that you can study and drill on the board. Each course comes at several rating levels, so the lines match the opposition you actually face.

Two different rules for the two sides. Your side plays the theoretically best moves, verified with the engine. The opponent's side plays the moves that are most popular at your chosen rating level — the replies you are genuinely likely to meet, drawn from millions of rated games in that rating window — rather than obscure engine lines you will never see over the board. Where opponents commonly go wrong, the course shows you how to punish it.

Opening guides are written articles that explain the ideas, plans and typical pawn structures behind an opening in plain language — the "why" behind the moves, to read alongside the courses and puzzles.

Opening traps are the short, tricky lines where one side can win material or deliver a quick mate if the opponent slips. Each trap page walks you through the tempting mistake, why it works, and — just as important — how to refute it so you don't fall for it yourself.

The puzzles come from Lichess's open (CC0) puzzle database — positions taken from real games and verified by an engine. We tag them by opening and by difficulty, so you can drill tactics specifically in the openings you are studying, at a rating level you choose.

A lab is your own opening workspace. You build a tree of moves and variations on the board, add notes and comments, import your games into it, and run engine analysis — all saved to your account and synced across your devices.

A lab is split into chapters, and chapters can hold subchapters, so a large opening tree stays readable. Any variation you branch off can become its own sub-section, and Ochess can auto-organise the tree by its forks so related lines are grouped together. You move between them from the chapter panel beside the board.

Both let you rehearse a line, with different amounts of help. In study mode the opponent replies automatically and a green arrow points to the right move, so you learn the line by playing through it. In training mode that help is switched off and you play your side from memory, with Ochess telling you immediately whether each move was right. Study a line first to learn it, then train it to lock it in.

Yes. If you get stuck during training you can ask for a hint — the board shows an arrow toward the right move. You can also attach your own reminder note to any move, so your personal hint appears the next time you drill that line.

Your account details, the games you import, your analysis and repertoire, and the labs you create. Your games and analysis are private to you unless you choose to share a lab. See the Privacy Policy for the full details.

You can delete your account at any time from your profile page. This erases your games, repertoire, labs and messages. See the Privacy Policy for what is briefly retained in backups.

Email support@ochess.app. Ochess is a personal project in active beta, so feedback genuinely shapes what gets built next.