Sudoku ∞ - Train your brain

Sudoku ∞ is a premium Sudoku puzzle game built for players who want more than the same nine-by-nine grid every day. Solve Classic Sudoku, then unlock Killer, Thermo, Arrow, Sandwich, Renban, Jigsaw, X-Sudoku, Hyper, Anti-Knight, Anti-King, Non-Consecutive, Odd/Even and Miracle. Thirteen variants, one elegant app. Always offline. Always free to play.


🧩 GAME MODES

• Beginner -Easy Sudoku puzzles with hints, notes and gentle feedback. The kindest place to learn the game.
• Pro -Hard Sudoku for confident solvers. No hints. Scored solves. Undo with a quick break.
• Crazy -Seventeen givens. The minimum any Sudoku puzzle can have. No hints, no undo, no notes. Pure deduction.
• Daily Challenge -One puzzle a day for everyone. Build your streak.


🎯 13 SUDOKU VARIANTS

Same 9×9 grid, different rules:

• X-Sudoku -diagonals must contain 1–9
• Hyper Sudoku -four extra 3×3 windows
• Jigsaw / Squiggly -irregular regions replace the boxes
• Killer Sudoku -sum cages, no givens
• Odd / Even -shaded cells must hold the right parity
• Thermo -digits along a thermometer strictly increase
• Arrow -pill cell equals the sum along the arrow shaft
• Sandwich -exterior clues sum the digits between 1 and 9
• Renban -line digits form a consecutive set
• Anti-Knight -no two cells a knight's move apart share a digit
• Anti-King -same idea, king's move
• Non-Consecutive -adjacent cells differ by more than 1
• Miracle -Anti-Knight + Anti-King + Non-Consecutive, the famous Cracking the Cryptic ruleset


💡 BUILT FOR REAL SOLVERS

• Hint engine names the technique. When you tap Hint, the app tells you exactly what's at play -Naked Single, Hidden Single, Naked Pair, Pointing, X-Wing -and explains why.
• Pencil marks (Notes) for tracking candidates, with a 3×3 sub-grid layout in every empty cell.
• Same-digit highlighting on selection. Tap a 5 and every other 5 lights up.
• Row, column and box of the selected cell get a subtle tint so you can see your constraints at a glance.
• Conflict highlighting -invalid placements turn red instantly.
• Auto-completion -when the last correct digit lands, the win celebration fires automatically. No "Done" button to remember.
• Undo with a watch-the-ad option in Beginner and Pro.


✨ A PREMIUM EXPERIENCE

• Hand-crafted dark theme with deep navy surfaces and warm gold accents.
• Real light theme that switches at the tap of a toggle.
• Custom colours for the grid digits and the surface.
• Smooth digit-place animations and tactile haptic feedback.
• Premium typography on the grid -every number readable at a glance.
• Designed for foldables, tablets and small phones alike.


📊 STATS & PROGRESS

• Per-mode best times.
• Completion counts.
• Consecutive-day streak counter on the home screen.
• Daily challenge: complete every day, never break the streak.


🔒 PRIVACY-FIRST

• Plays fully offline. No login required.
• No analytics. No tracking pixels.
• An age-gate at first launch sets a kid-friendly experience for players under 13: zero ads ever for that profile.
• For everyone else, a single full-screen ad shows after a completed puzzle or when you undo -never mid-puzzle, never on the grid, with at least five minutes between any two ads.


🆓 ALWAYS FREE TO PLAY

The full game is free. We support development with the occasional, well-mannered interstitial ad and that's it -no paywalls, no daily-puzzle limits, no premium-only difficulty levels.


🧠 PUZZLES YOU CAN ACTUALLY TRUST

Every puzzle in Sudoku ∞ is generated from scratch and verified to have exactly one solution. Whether you're solving an Easy Beginner puzzle or a 17-given Crazy Mode grid, you can be sure the answer exists and is unique. No reused puzzles. No guessing required for the logical solves.