Knight & Castle

Play Stockfish, learn with AI

Free · Designed for iPad. Not verified for macOS.

Offline Stockfish chess with an AI coach that explains your mistakes. Now with iPhone Duo and landscape support. Play real chess offline against Stockfish—and understand every move with clear AI feedback. Knight & Castle is a focused chess trainer for players who want a strong opponent, practical move feedback, and a clean board—without an account, matchmaking, or an internet connection. PLAY AND IMPROVE OFFLINE • Play against Stockfish from Beginner to Expert • Choose White or Black • No account or online opponent required • Practice anywhere, even without Wi-Fi or cellular data UNDERSTAND EVERY MOVE After each move, see whether it was a Best Move, Good Move, Inaccuracy, Mistake, or Blunder. Compare your move with the engine’s recommended alternative and find the moment that changed the game. Whether you are learning the rules or sharpening your strategy, Knight & Castle helps you improve at your own pace. ■ Five difficulty levels Choose Beginner, Easy, Medium, Hard, or Expert, and play as White or Black. ■ Move review & AI coach The engine grades every move you make. An on-device AI coach explains in plain language what worked, what did not, and what to focus on next. When the game ends, Game Review summarizes your accuracy, key moments, and the moves that mattered most. ■ Learning mode • Hint: see a recommended move when you are stuck • Undo: take back your last move • Move history: revisit any position • Opening names: recognize the opening you are playing • Share your game: export it as PGN ■ Made for iPhone, iPad, and iPhone Duo Play in portrait or landscape. On iPhone Duo, fold the device for a board-first view or unfold it for a larger board beside the control panel. ■ More features • Toggle board coordinates (a–h, 1–8) • Resume your game after closing the app • The chess engine runs on your device, so you can play offline The AI coach comments require a device that supports Apple Intelligence. On other devices, the engine still grades each move and shows the recommended alternative.

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What's new in version 2.4 ■ iPhone Duo support • Folded: a clean, board-first screen so you can focus on the game • Unfolded: a roomy layout with the board and control panel side by side ■ Landscape support • Turn your iPhone or iPad sideways for a larger board with the controls beside it ■ A sharper AI coach • Never mixes up your move with the recommended move • Clearly warns you when one of your pieces can be captured • Headlines now point out what each move actually did, instead of repeating the same phrases ■ Easier to read • On smaller screens the board stays large • Coach comments scroll neatly below the board • Ads now appear only during a game ■ Bug fixes • Fixed an issue where tapping New Game as Black sometimes didn't start the game • Fixed an issue where the computer could stop responding right after relaunching the app

Version 2.4

The developer, KAZUYUKI TAJIMA, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Used to Track You

    The following data may be used to track you across apps and websites owned by other companies:

    • Location
    • Identifiers
    • Usage Data
    • Diagnostics

  • Data Not Linked to You

    The following data may be collected but it is not linked to your identity:

    • Location
    • Identifiers
    • Usage Data
    • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Seller
KAZUYUKI TAJIMA
Size
8.2 MB
Category
Board
Compatibility
Requires iOS 26.0 or later.
  • iPhone
    Requires iOS 26.0 or later.
  • iPad
    Requires iPadOS 26.0 or later.
  • Mac
    Requires macOS 26.0 or later and a Mac with Apple M1 chip or later.
  • Apple Vision
    Requires visionOS 26.0 or later.
Languages
English and 7 more
  • English, French, German, Japanese, Portuguese, Spanish, Swedish, Traditional Chinese
Age Rating
4+
Copyright
© 2026 Kazuyuki Tajima
  • Developer Website
  • Privacy Policy

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