Blindfold Chess App: User Guide

💡 Core Idea: Play Silently with Eyes Closed

The core idea of this app is that you play with your eyes closed and without using your voice. Simply put on earplugs, close your eyes, control the pieces by just touching the screen-quadrants with your thumbs. You can enjoy a completely immersive, audio-guided chess experience, without disturbing others.

✨ Key Features

• True Blindfold Experience: No visual chess board is displayed during gameplay. All interaction is through touch input and audio feedback.
• Multi-Board (Simultaneous) Play: Challenge yourself by playing on up to 8 different chess boards simultaneously. The app seamlessly guides you from one board to the next.
• Intuitive Touch Input: Select squares and promotion pieces using a simple, repeatable quadrant-based tapping system.
• Comprehensive Audio Feedback:
  • Announces the current board number when playing multiple boards.
  • Announces moves (e.g., "White pawn from e2 to e4").
  • Confirms special moves like captures and castling.
  • Notifies you of game states (Check, Checkmate, Stalemate, Draw).
  • Alerts you to illegal moves.
  • Guides you through promotion choices.
• Chess 960 (Fischer Random) Support: Practice blindfold chess with random starting positions.
• Dynamic AI Opponent (Stockfish): Play against a strong chess engine with precise control over its difficulty, allowing you to set the AI's "thinking depth" from 1 (Easy) to 15 (Hard).
• Easy Promotion Choice: When a pawn promotes, the four touch quadrants display the actual chess piece icons (Queen, Rook, Bishop, Knight). Because the piece icons are always displayed in the same quadrants (for example, the Queen is always displayed in the top-left quadrant), you could even keep your eyes closed.
• Enhanced Undo Last Move: Correct mistakes by undoing the last full move (your move and the AI's response). In multi-board mode, it undoes the AI's move on the current board and then your move on the previous board.
• Cancel Selection: Easily reset your current square selection if you make a mistake.

🎮 How to Play

Starting a New Game

1. Open the App: The app starts on the Menu screen.
2. Select Boards: Choose the number of simultaneous games you wish to play (from 1 to 8).
3. Choose Your Color: In case of playing one board: select "White" or "Black" from the "Choose color" dropdown. Note: If you choose to play multiple boards, this setting is not available, and your color will alternate (White/Black) for each successive board.
4. Select AI Level (Depth): Choose a numerical value (1-15) from the "Level" dropdown. This directly sets how many moves deep the Stockfish AI will calculate, with higher numbers indicating a stronger opponent.
5. Select Variant: Choose "Standard" for regular chess or "Chess 960" for a random starting position. The starting position will be displayed visually on the menu screen.
6. Always Promote to Queen: By default, this option is checked, meaning your pawns will automatically promote to a Queen. Uncheck this option if you want to manually choose your promotion piece (Rook, Bishop, or Knight) during the game.
7. Start Game: Tap the "Start Game" button.

Using the Game Menu

During a game, tapping the white square in the center will open a menu with the following options:

• "Cancel Selection": If you've started selecting a square but want to reset, tap this button. It will clear your current partial selection. A shortcut for this is to swipe from right to left over at least 25% of the screen width (without opening the game menu).
• "Undo Last Move": Tap this to undo the last full move (your move and the AI's response). In multi-board mode, it will undo the current board's last (AI) move and then switch to the previous board to undo your last move.
• "Main Menu": Returns you to the main menu. Here you can review the 960 starting position and then click "Resume Game".
• "Resume Game": Returns you to your current game.

Making a Move (Square Selection)

The game screen consists of four large, touchable quadrants:

• TL (Top Left)
• TR (Top Right)
• BL (Bottom Left)
• BR (Bottom Right)

When you use the app in full-screen mode, you can use your thumbs to tap these quadrants. To select any square of the 8x8 chessboard, you will make three consecutive taps on these quadrants. Each tap narrows down the selection to a smaller quadrant, eventually pinpointing a single square. Visual help is provided during play to get acquainted with this system.

Example 1: tapping BR BL TL selects E2 (for White)

• Tap 1 (BR): Selects the bottom-right 4x4 quadrant (e1-h4).
• Tap 2 (BL): Selects the bottom-left 2x2 quadrant (e1-f2) within the previous 4x4 (e1-h4).
• Tap 3 (TL): Selects the top-left 1x1 square (e2) within the previous 2x2 (e1-f2).

(Note: The actual quadrant sequence for a specific square depends on your chosen color (White or Black) as the board is oriented from your perspective.)

Other examples:

• TR TR TR selects h8 (or a1 if you have the black pieces).
• TL BR BR selects d5 (or e4 if you have the black pieces).

Steps to Make a Move:

1. Select the "From" Square: Perform three taps to select the square of the piece you want to move.
   • The app will announce your chosen square (e.g., "White pawn from e2").
2. Select the "To" Square: Perform another three taps to select the destination square for your piece.
   • The app will announce the destination square (e.g., "to e4").
   • If the move is illegal, you will hear "That's an illegal move". The square selection is undone so that you can try again.

Promotion

If your pawn reaches the last rank and you have unchecked the "Always promote to queen" option in the menu:

1. After selecting the "to" square for your pawn's promotion, the app will announce: "Choose a promotion piece."
2. The four touchable quadrants will now visually display the chess piece icons in your color, representing the promotion options:
   • Top Left: Queen
   • Top Right: Rook
   • Bottom Left: Bishop
   • Bottom Right: Knight
3. Tap the quadrant corresponding to the piece you wish to promote to.
   • The app will confirm your choice by finishing the move sentence with – for example – "promoted to Queen". The full sentence that you've heard, might then be: "White pawn from f7 takes g8 – choose a promotion piece – promoted to Queen".

🧠 Tips for Blindfold Play

• Visualize the Board: Mentally keep track of piece positions and board coordinates for each active game.
• Listen Carefully: Pay close attention to all audio cues for moves, game states, and board changes.
• Practice Coordinates: Familiarize yourself with algebraic notation (e.g., a1, h8) thoroughly.
• Start Simple: Begin with standard chess, 1 board, and easier AI levels (lower depth), then gradually increase complexity.
• Don't Be afraid to Undo: Use the "Undo Last Move" button to review and correct mistakes, especially when learning.
• Take care of your health: Some professional players advice against playing too many boards blindfolded. Take care of your brain ❤️

Enjoy your blindfold chess journey!

📚 Frequently asked questions

Is this app free?

Yes, blindfold-chess.app is free for individual, private, non-commercial use. Also, if you are a chess teacher or online content creator, you can show how blindfold-chess.app works and even play full games. Make sure the URL "blindfold-chess.app" is visible at least a few seconds. For using this app or parts of this app outside of the domain "blindfold-chess.app" you need a license. For more information, see the "Licenses" and the "Blindfold Chess App: License Agreement".

Can I download the app?

Yes. This app is a Progressive Web App (PWA) and can be installed on your device. When you open the app in a browser and see "blindfold-chess.app" in the URL bar, then, depending on your browser (e.g. Chrome, Edge, etc.), you might see, near the URL bar, an icon for installing this app on your device. After installing, the app will appear on your home screen, and you can launch it from there. If clicking on the app icon opens a regular browser tab, then only a shortcut has been placed on your home screen. Try installing the app via a different browser.

Can I use this app offline?

Yes. There are two options:

1. Install the app (see above). This will allow you to use the full app without internet connection.
2. Use the app without installing it. After starting a game via the "Start Game" button, the app won't access the internet anymore.

Can I play against a human opponent?

No, not yet. This might be possible in the future, depending on the interest of the community. You can ask your favorite chess website to buy a license to use this app on their website for games between humans. Then you might play blindfolded against a human who doesn't play blindfolded, or create a game that requires the other player to also play blindfolded.

Blindfold Chess App: Creator Guide

This section is for people interested in creating chess tools.

📜 Licenses

• The idea of the touch-based input system, with 3 taps to select a square, is unique – a proprietary feature found exclusively on blindfold-chess.app and owned by Symbolinker (symbolinker@gmail.com). Licenses are available if you're interested in using this idea, or parts of this app, in your own application/website/etc. More information about this can be found under "Blindfold Chess App: License Agreement".
• The file stockfish.js that is used, was downloaded from https://github.com/lichess-org/stockfish.js (the latest release of 2018). For its license, see the official Stockfish repository.
• The file chess.js that is used, was downloaded (as a chess.ts file) from https://github.com/jhlywa/chess.js/pull/493 (at 28-05-2025). For its license, see the chess.js repository.

🤝 Contributing

Requests for improvements, bug fixes and new features are welcome. Programmers might start a discussion, report an issue or open a pull request. If you're not a programmer, you can e-mail me at symbolinker@gmail.com and we'll do our best to implement your suggestions.

Blindfold Chess App: License Agreement

This License Agreement (the "Agreement") governs your use of the Blindfold Chess App (the "App"), located at https://blindfold-chess.app, and its associated features, including but not limited to its unique touch-based input system, audio feedback, overall design, and its associated source code and development materials hosted at https://github.com/blindfold-chess/blindfold-chess/. By accessing or using the App, you agree to be bound by the terms of this Agreement.

1. Ownership and Copyright

The Blindfold Chess App, including its unique touch-based input system and overall design, is the proprietary intellectual property of Symbolinker (symbolinker@gmail.com) and is protected by copyright laws. All rights not expressly granted to you in this Agreement are reserved by Symbolinker.

2. Permitted Uses

2.1. Free Individual and Personal Use

You are granted a free, non-exclusive, non-transferable license to use the App for your individual and personal purposes. This includes, but is not limited to, practicing, training, and improving your blindfold chess skills. This permission extends to individuals who may earn income from professional chess activities, such as tournament play, coaching, or content creation, provided their use of the App itself remains personal and does not involve the commercial reproduction, distribution, or integration of the App's unique features into other commercial products or services.

2.2. Educational and Content Creation Use

Chess teachers, online content creators, and similar educational entities are permitted to use and showcase the App for instructional or demonstration purposes, including playing full games. When doing so, the URL "blindfold-chess.app" must be visibly displayed for at least a few seconds in any content created (videos, streams, screenshots, etc.).

3. Restricted Uses

Unless explicitly granted through a separate commercial license agreement with Symbolinker, the following uses are strictly prohibited:

• Commercial Use: Any use of the App or its unique features for direct or indirect commercial gain, including but not limited to selling access to the App, incorporating it into a paid product or service, or using it for advertising purposes.
• Reproduction and Distribution: Copying, reproducing, distributing, modifying, creating derivative works of, publicly displaying, or publicly performing any part of the App, including its code, design, or unique features, outside of the blindfold-chess.app domain.
• Sub-licensing: Granting sub-licenses to others to use the App or any of its components.
• Use in Other Applications/Websites: Integrating the unique touch-based input system or any other proprietary elements of the App into other applications, websites, or platforms without a specific license.

4. Commercial Licensing

For any use beyond the "Permitted Uses" described in Section 2, particularly for commercial purposes or integration into other applications/websites, a separate commercial license is required. Please contact Symbolinker at symbolinker@gmail.com to inquire about licensing opportunities.

5. Third-Party Licenses

The App incorporates third-party software components, each governed by their respective licenses:

• Stockfish.js: Used for the AI opponent. Its license can be found at the official Stockfish repository.
• Chess.js: Used for chess logic. Its license can be found at the chess.js repository.

Your use of the App acknowledges and abides by these third-party licenses where applicable.

6. Disclaimer of Warranties

The App is provided "as is," without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and non-infringement. In no event shall Symbolinker be liable for any claim, damages, or other liability arising from your use of the App.

7. Governing Law

This Agreement shall be governed by and construed in accordance with the laws of The Netherlands, without regard to its conflict of law principles.

8. Changes to This Agreement

Symbolinker reserves the right to modify this Agreement at any time. Your continued use of the App after any such modifications constitutes your acceptance of the new terms.

For any questions regarding this License Agreement, please contact Symbolinker at symbolinker@gmail.com.