Sudoku
Fill the grid so every row, column, and box holds 1–9 with no repeats.
How to play
- Each of the nine rows, nine columns, and nine 3×3 boxes must contain the digits 1–9 exactly once.
- Pick any difficulty — any difficulty counts for your streak.
- Some days add a variant (Killer, Thermo, Sandwich, Miracle…) with an extra rule.
Controls
- Tap a cell, then a number. Use notes to pencil in candidates.
Techniques
Naked single
A cell whose row, column, and box already rule out eight digits — only one can go there. Scan for these first; every placement creates new ones.
Hidden single
A digit that fits in only one cell of a row, column, or box, even if that cell has other candidates. Check each unit digit-by-digit: where can the 7 go?
Naked pair
Two cells in one unit that share the same two candidates lock those digits between them — erase both digits from every other cell in that unit.
Pointing pair
When a box's only candidates for a digit sit in one row or column, that digit must be there — eliminate it from the rest of that row or column outside the box.
Example
5 3 . 6 . . . 9 8
Fill so every row, column, and 3×3 box holds 1–9 exactly once.
Try it
A mini 4×4 board — every row, column, and 2×2 box needs 1–4 exactly once. Each empty cell has only one possible digit. Tap a cell, then a digit.
Find the only digit that fits each empty cell.
Tip · Hunt for cells with only one possible digit; pencil-mark the rest.
Play Sudoku →