Sudoku - No Ads

A no-nonsense Sudoku app. No ads, no tracking, no subscriptions. Just the puzzle.

Difficulty levels that actually mean something:

Easy — solvable using naked singles only, no notes needed.
Medium — requires hidden singles and naked pairs.
Hard — requires hidden pairs, naked triples, pointing pairs, and box/line reduction.
Expert — requires X-Wing and Swordfish.

Every puzzle has exactly one solution and is solvable without guessing. Higher difficulties require more advanced techniques, not just fewer starting numbers.

Features:

• Light and dark themes (or follow system)
• Notes system with auto-cleanup (placing a correct number removes that candidate from related rows, columns, and blocks)
• Digit buttons hide once all 9 instances of a digit are placed, so you can see at a glance what's left
• Long-press a digit to highlight it across the board, or long-press again to flip into notes mode
• Undo for mistakes, clear for corrections
• Smart hints that teach you solving techniques — but only after you've applied the ones you should already know, and the wait scales with how accurate your notes are
• Configurable mistake and hint limits (0-3), with a one-minute time penalty per mistake
• Timer with auto-pause
• Sound effects, switchable off
• Auto-save and resume
• Per-difficulty statistics with win rates and best times
• Available in English and Spanish

No accounts. No permissions. No data collection. Just Sudoku.