Sudoku
Fill the 9×9 grid so every row, column, and box contains 1-9. The classic logic puzzle.
About Sudoku
Sudoku traces back to a 1979 American puzzle magazine before a Japanese publisher popularized it under its current name in the 1980s, and it exploded into a worldwide phenomenon in newspapers and puzzle books by the mid-2000s. The rules are famously simple: fill a 9×9 grid, split into nine 3×3 boxes, so that every row, column, and box contains the digits 1 through 9 exactly once. No arithmetic is involved — Sudoku is pure logical deduction, which is exactly why it appeals to people who don't otherwise think of themselves as "puzzle people."
This version generates a brand-new, uniquely-solvable puzzle every time you play — no two games repeat, and every puzzle is verified to have exactly one solution before it's handed to you, so you'll never hit a dead end caused by a bad puzzle. Choose from three difficulty levels that control how many starting digits are given: Easy for a relaxed, mostly-fillable grid, Medium for a genuine but fair challenge, and Hard for grids that demand real chains of deduction. A built-in mistake counter (three strikes and the puzzle ends), a running timer, and three hints per game round out the tools, but the core experience stays exactly what makes Sudoku endure: a quiet, screen-sized logic problem you can chip away at anywhere.
How to Play
- 1Tap a cell to select it, then tap a number 1-9 to fill it in
- 2Every row, column, and 3×3 box must contain each digit 1-9 exactly once, with no repeats
- 3Given numbers (shown in white) are fixed and can't be changed
- 4Use Erase to clear a cell you've filled in, or Hint to reveal a cell's correct value (3 hints per game)
- 5Fill every cell correctly to win — three wrong entries ends the puzzle
Tips & Strategy
- Scan for rows, columns, or boxes that already have 7-8 of their 9 digits filled — those are the fastest cells to solve.
- Look for a digit that's missing from a whole box, then check which of that box's empty cells is the only one where it could legally go.
- Work systematically left-to-right, top-to-bottom rather than jumping around — it's easier to spot patterns you've already half-solved.
- If a cell has only one possible digit once you account for its row, column, and box, that's a guaranteed placement — no guessing needed.
- Save your hints for when you're genuinely stuck, not for cells you could work out with a bit more scanning.
Frequently Asked Questions
Is Sudoku a math puzzle?
No — despite using digits 1-9, Sudoku involves no arithmetic at all. It's purely a logic and pattern-placement puzzle; you could just as easily play it with nine different symbols instead of numbers.
Does every puzzle have only one solution?
Yes. Every puzzle generated here is checked to confirm it has exactly one valid solution before you start, so a correct, careful line of logic will always get you there.
What's the difference between the difficulty levels?
Difficulty controls how many starting numbers are given: Easy grids start with the most digits filled in, Hard grids start with the fewest, requiring longer deduction chains to make progress.
How many mistakes am I allowed?
You can make up to three incorrect entries before the puzzle ends. Use Hint if you're stuck rather than risking a guess.
