MegaSudoku - Intuitive & challenging puzzles

Welcome to the game, the definitive, 100 % free Sudoku experience designed for everyone—from casual commuters to hard-core number-crunchers. Every single grid has been computer-verified to guarantee exactly one unique solution, mirroring the same rigorous standards used in international Sudoku championships. Whether you have three minutes on the bus or an entire evening to spare, Ciao Sudoku automatically saves your progress so you can pause and resume at will, offline and ad-free.

KEY FEATURES

• Five Precision-Tuned Difficulties

– Very Easy (45 + clues): perfect for learning the rules

– Easy (35–44 clues): smooth brain-teasing

– Medium (28–34 clues): balanced challenge

– Hard (22–27 clues): advanced tactics required

– Evil (exactly 17 clues): the absolute minimum, world-class difficulty

• Three Input Modes

– Number First: tap a digit, then tap every cell you want it in—ideal for speed runs.

– Cell First: tap a cell first, then choose the number—great for precision.

– Popup: long-press a cell for a compact numpad—perfect for one-hand play on phones.

• Universal Design

– Native layouts for both smartphones and tablets, portrait or landscape.

– Dark, light, and high-contrast themes to protect your eyes at night.

• Smart Progress Tracking

– Auto-save after every move.

– Visual badges on incomplete grids so you can spot them instantly in the graphical puzzle list.

• Offline Freedom

– No ads, no data, no Wi-Fi needed ever. Download once, play forever.

• Custom Puzzle Editor

– Paste or hand-enter any 81-character string (0 or . for blanks) and the app will validate solvability, then let you play or share it.

• Beautiful & Open Source Assets

– Icons from openclipart.org under CC0 license.

– Core engine powered by the open-source solver at ciaosudoku.com—fully transparent and auditable.

HOW TO PLAY & PRO TIPS

Choose Your Puzzle

– Open the graphical list, tap any thumbnail, and pick a difficulty. Incomplete grids shimmer faintly so you never lose your place.

Fill the Grid

– Use the input mode you prefer (change it anytime in Settings ▸ Controls).

– Long-press a filled cell to clear it instantly.

– Tap the pencil icon to toggle note mode—write small candidate numbers in each corner.

Check & Validate

– Tap the checkmark to highlight conflicting numbers in red.

– Tap “Hint” to auto-fill a correct digit; no penalty, but your streak badge turns gray if you use it.

Master Advanced Techniques

– Naked Triple: three cells in a unit contain the same three candidates—eliminate those digits elsewhere.

– X-Wing: spot rectangles of matching candidates to wipe rows or columns.

– Swordfish & Jellyfish: bigger versions of X-Wing, perfect for Evil grids.

– Coloring / Chains: mark alternating true/false candidates to expose contradictions.

Pro Settings for Power Users

– Enable “Auto-erase notes” so solved digits vanish from candidate lists automatically.

– Turn on “Highlight peers” to see every row, column, and box instantly when you touch a cell.

– Use gestures: swipe left/right to undo/redo, pinch to zoom on tablets.

Enjoy endless, pure Sudoku—crafted for clarity, validated for uniqueness, and built to travel with you wherever you go.