The classic 1–9 logic puzzle on a 9×9 grid. Fill every cell so no row, column, or 3×3 box repeats a digit. Tap a cell, then tap a number. Notes and hints included. Every puzzle has exactly one solution — solvable by logic alone.
Sudoku
The classic 1–9 logic puzzle on a 9×9 grid. Three difficulties, notes, and hints — every puzzle has a unique solution.
📖 How to Play
- Tap an empty cell to select it, then tap a number on the pad
- Each row, column, and 3×3 box must contain 1–9 with no repeats
- Toggle Notes ON to pencil in small candidate numbers
- Erase clears the selected cell; Hint reveals one correct cell (score penalty)
- A wrong digit is counted as a mistake and shown in red
- On desktop use number keys, arrow keys, and N (toggle notes)
- Fill the whole grid correctly to win — score from time, mistakes, and hints feeds the global leaderboard
About this game
Sudoku is the number-placement logic puzzle: fill a 9×9 grid with the digits 1–9 so that no row, no column and no 3×3 box repeats a digit. It requires no arithmetic at all — only deduction — which is exactly why it has stayed popular.
Every puzzle here is generated with a guaranteed unique solution, so you never have to guess: each cell can always be determined by logic alone. Three difficulties are available — Easy, Medium and Hard.
A notes mode lets you pencil in candidate digits, reproducing the same thought process you'd use on paper. If you get stuck, a hint reveals one correct cell at a score penalty. Your score is based on time, mistakes and hints used.
Tips & strategy
- Start by finding rows, columns or boxes with only one empty cell — those certainties tend to cascade
- Scan one digit at a time across the whole grid to narrow where that digit can legally go
- Using notes to write candidates makes cells with a single remaining candidate visually obvious
- On Hard you'll need indirect deductions, such as noticing that within a box a digit can only sit in one particular row
- Mistakes cost score, so skip any cell you aren't certain about and fill the forced ones first
FAQ
Q. Is every puzzle solvable?
A. Yes — each one is generated with a unique solution, so it can always be solved by pure logic without guessing.
Q. Can I choose a difficulty?
A. Yes: Easy, Medium or Hard. Harder settings start with fewer given digits.
Q. How do notes work?
A. Turn Notes on and tap a digit to pencil it into the selected cell as a small candidate. On desktop, N toggles the mode.
Q. How is score calculated?
A. From your clear time plus penalties for mistakes and hints used — fast, clean solves score highest.