Do I need an internet connection to play?#
Regular puzzles and the core solving tools are designed to work without an internet connection. An internet connection may be needed for Google Play purchases, restoring Premium, or refreshing services used by Daily Challenge comparisons.
How is my progress saved?#
Lab Sudoku keeps your active puzzles, candidates, checkpoints, bookmarks, and statistics in the app. Before reinstalling or changing devices, check the current app options for any available export or transfer workflow; do not assume that progress is automatically available on a new device.
What do the difficulty levels mean?#
Lab Sudoku offers five levels, from Simple through Diabolical. Difficulty describes the solving challenge, not a promise about how long a puzzle will take. Guided Hints can help explain the next logical step when a puzzle becomes difficult.
What are Guided Hints?#
Guided Hints explain a logical move rather than simply revealing a completed solution. The Guided Hints and techniques guide covers singles, subsets, box-line interactions, wings, and fish patterns.
Can I enter my own puzzles?#
Yes. You can enter a puzzle manually or scan a printed or on-screen puzzle with the camera. Review the recognised grid before starting, then save it in My Puzzles if you want to return to it later. See Creating and importing puzzles.
Does camera import upload my photos?#
The camera-import workflow is intended to recognise a Sudoku grid and let you review it before solving. Check the app’s current permission and privacy prompts before granting camera access, and delete any source image you no longer need. For the authoritative data-handling details, see the Lab Sudoku Privacy Policy.
Why did the camera recognise my puzzle incorrectly?#
Use a clear, well-lit image with the complete grid visible and as little perspective distortion as possible. Review every cell after scanning, correct the recognised entries manually, and avoid starting the puzzle until the grid matches the source.
What are checkpoints and bookmarks?#
A checkpoint saves a named point in the current puzzle so you can explore a difficult branch and return to it later. A bookmark helps you find a puzzle again. Premium increases the available limits for saved imports, checkpoints, and bookmarks.
How do Daily Challenges work?#
Daily Challenges provide a new puzzle and let you review your personal progress over time. The available difficulty and comparison options depend on your current access level. See Daily Challenges and statistics for details.
Is Premium a subscription?#
No. Lab Sudoku Premium is a one-time Google Play purchase. It adds advanced Guided Hint techniques, higher limits, Premium themes and fonts, all Daily Challenge difficulties, and optional anonymous community comparisons. See Lab Sudoku Premium for purchase and restore instructions.
How do I restore Premium after reinstalling?#
Use the same Google Play account that made the purchase, open Settings → Premium, and choose Restore Purchases. If the entitlement is not found, check the active Play account and network connection before trying again.
Where can I get help?#
Start with Lab Sudoku troubleshooting, then visit the shared Support page for the information to include when reporting a problem. For privacy questions, contact privacy@lunarhut.com.