Opening Crown

Hervé C.

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About this app

Master chess openings with Opening Crown — your opening coach powered by Stockfish.

Opening Crown is the perfect app for chess players who want to learn and master theoretical openings. Whether you're a beginner or intermediate player, the app guides you step by step through the key lines of classical openings.

🧠 Powered by Stockfish Opening Crown embeds Stockfish, the world's best open-source chess engine (the same engine used by Lichess.org), directly in the app. This means fast, accurate real-time analysis — no internet connection required.

📖 Theory Mode Learn openings move by move. The app guides you through main lines and variants, flags your mistakes, and rewards correct play.

🔭 Exploration Mode Freely explore any position. Stockfish analyses every move in real time and displays: • Theory moves from the selected opening (in green) • Stockfish's best move (in cyan) • Move classification: good, inaccurate, mistake • Live centipawn evaluation bar Opening data comes from the Lichess database (500,000+ games), loaded at startup.

⚔️ Combat Mode Play against the computer from 400 to 2200 ELO. Stockfish adapts its strength and rates each of your moves outside the opening: • !! Best move (+5 pts) • ! Excellent (+2 pts) • ✓ Good move (0 pts) • ?! Inaccuracy (-5 pts) • ? Mistake (-10 pts) • ?? Blunder (-15 pts) During the theoretical opening phase, arrows guide you — scoring begins once you leave the book.

🌍 4 languages: Français, English, Deutsch, Español

Built with: React, Stockfish (WebAssembly), Lichess Open Database

What’s new

Combat Mode improved: AI now plays at the correct ELO level, hint button (-5 pts), pawn promotion dialog, automatic game resume.
Alien Gambit opening: 3 theory lines added (refutation, Bg4 trap, solid line).
Android fixes and optimisations.