Only Opens: Chess Openings

Stop forgetting your openings the moment you step away from the board.

Only Opens is the chess opening trainer built for serious improvement. Instead of passively reading theory, you train actively — playing moves from memory against a smart engine, reviewing the lines you actually need, and tracking your progress over time.

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🎓 LEARN SMARTER WITH SPACED REPETITION
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Only Opens uses the SM-2 spaced repetition algorithm — the same science behind language learning apps — applied to chess openings. Lines you struggle with come back sooner. Lines you've mastered fade into the background until you need a refresh. You study less, remember more, and build a repertoire that actually sticks.

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♟ 1,300+ OPENINGS IN YOUR POCKET
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Browse and train with the complete ECO opening classification — from the Ruy Lopez and Sicilian Defense to the King's Indian, Caro-Kann, French, and hundreds of lesser-known lines. Every opening comes with:

• Win rate statistics (White / Draw / Black) from real games
• Known counters and theoretical responses
• Move-by-move animated playback
• Direct jump to any position in the Explorer

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🤖 PLAY AGAINST 6 AI PERSONAS
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Each card in your feed pairs you with a unique engine persona — Tactical Attacker, Positional Strategist, Dynamic Gambiteer, Endgame Specialist, Solid Defender, and Theoretical Genius. Play out the opening against your assigned opponent and see if your memorisation holds up in a real game.

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🔭 INTERACTIVE OPENING EXPLORER
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Explore the entire opening tree on a beautiful interactive board. Every move shows frequency, win rates, and known continuations pulled from the database. Three modes to choose from:

• Free Play — move both sides manually to analyse any position
• Vs AI — test your defences against a Stockfish-powered engine
• Analysis Mode — get a real-time Stockfish evaluation bar and best-move suggestion for any position

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📊 REVIEW SESSION & PROGRESS TRACKING
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Your Profile tab shows your full stats at a glance: openings mastered, total positions studied, reviews due today, and your daily training streak. Start a focused review session to work through everything that's due, with automatic colour-side detection so you always practice from the correct perspective.

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📁 IMPORT YOUR OWN PGN REPERTOIRE
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Already have an opening repertoire in a PGN file? Import it directly into Only Opens. The app will parse your games, match the moves against the built-in database, and update your spaced repetition queue automatically — crediting moves you've already played and flagging divergences from your prep.

Export your studied repertoire back to PGN any time to use in other chess software.

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🎨 BEAUTIFUL, CUSTOMISABLE BOARD
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Four board themes: Classic Navy Blue, Forest Emerald Green, Walnut Wood, and Cyber Orange. Drag-and-drop or tap-to-move. Full board flip. Move highlights, legal move indicators, king-in-check alerts, and last-move display. Fully accessible with screen reader support.

Whether you're a club player trying to remember the Najdorf, a beginner building your first opening repertoire, or an experienced player drilling edge lines before a tournament — Only Opens gives you the tools to study smarter, not longer.

Download free. Start remembering.