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Live opening-book matching
As you play, the panel filters to the openings and variations still reachable from your exact position - by move order and by transposition.
Desktop chess opening trainer
Learn chess openings by playing them.
Make moves on the board and the Opening Books panel narrows to the lines you're still in — telling you the moment you go off-book, which variation you were in, and how to continue. Then drill it from memory.
- 3,700+ named lines
- Works fully offline
- Free during beta
Everything you need to actually know your openings
Not a database dump - a focused trainer that reacts to every move.
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Off-book detection
Leave known theory and you're told exactly where - “Off-book after 6. h3. Last book move: 5…a6 in the Najdorf” - then keep playing freely.
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Animated line replay
Click any move in a line and the board steps through it ply-by-ply, so castling, en-passant and undo all stay perfectly correct.
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Variations & book moves
See the named variations branching from here, with the next book moves as one-click chips. Generic labels never hijack your “active opening”.
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Guide-arrow overlay
Toggle on-board arrows — green for the main line, orange for alternatives with a count of how many lines run through each.
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Accounts & favourites
Optional sign-in to favourite openings and variations, save custom lines, and sync them. Guest play always works, fully offline.
New
Three ways to memorise, not just view
The Practice tab turns study into active recall. Pick a line or an opening and put your memory to the test.
- Blind Mode - complete a variation entirely from memory, first as White, then as Black. The moves stay hidden.
- Match Mode - watch a line play out, then identify which variation it was. Build a streak and beat your best.
- Challenge Mode - play the correct book moves from a random side in a random variation of your chosen opening.
A closer look
Built to keep you focused on the position in front of you.
Study lines move-by-move
The selected variation shows played, current and upcoming moves, the next book moves, and every variation branching from the position - with optional autoplay for either side.
See the theory on the board
Guide arrows point out the main continuation and the alternatives, while the panel locks onto the matched opening only once the position is specific enough to mean something.
Free beta · Windows
Download OnBook Chess
A standalone Windows desktop app. The full opening database is bundled, so it works offline - no setup beyond the installer.
Download for Windows (.exe)🧪 This is a beta
OnBook Chess is still in testing. Some features may change and you might hit bugs - feedback is very welcome.
🛡️ Installing on Windows
The beta isn't code-signed yet, so Windows SmartScreen may warn you. Click More info → Run anyway to continue.