Free logic puzzle
Sudoku
Also known as Number Place
The classic number puzzle: a 9 by 9 grid, the digits 1 to 9, and pure logic.
In your browser, no account needed. Or get the app and play offline.
How to play
- Fill the grid so every row, column and 3 by 3 box holds the digits 1 to 9 exactly once.
- Tap a cell, then pick a number. Switch Notes on to pencil in what could fit.
- Stuck? A hint explains the next logical step. You never need to guess.
First moves
Hidden single
Pick a digit and one box. Look along the rows and columns that cross the box: wherever that digit already sits, it rules out a whole line of squares. When only one square in the box is left for the digit, it goes there. Repeat for every digit and box, and the grid opens up quickly.
Naked single
Some squares can only take one digit. Take an empty square and list what its row, column and box already hold. If eight different digits are taken, the ninth is the answer. Busy rows and columns are the best places to look, because they leave the fewest options.
Notes
When no single is left, switch Notes on and pencil the possible digits into each square of one row, column or box. Notes turn hidden patterns into visible ones. Keep them tidy: each time you place a digit, remove it from the notes in the same row, column and box.
Naked pair
If two squares in the same row, column or box can each only be the same two digits, say 4 and 7, those two digits belong to that pair. Cross 4 and 7 out of every other square in that row, column or box. The app's hints call this a naked pair.
Pointing pair
When a digit can only go in squares of one row inside a box, it must land in that row within the box. So the same digit cannot sit anywhere else in that row, outside the box. Cross it out there. This pointing pair often unlocks a hidden single in the next box.
Origin
The modern Sudoku was most likely designed by Howard Garns, a retired architect from Indiana, and first published in 1979 by Dell Magazines as Number Place.
In April 1984 Maki Kaji, president of the Japanese puzzle company Nikoli, introduced it in Japan. He shortened its long Japanese name, “the digits must be single”, to Sudoku: su means number, doku means single.
Wayne Gould, a retired judge from Hong Kong, wrote a program that makes the puzzles and brought them to The Times in Britain, which launched Sudoku on 12 November 2004.
Sources: Wikipedia: Sudoku
Why play it here
- Every puzzle has exactly one solution, and logic gets you there.
- Four levels: Easy, Medium, Hard and Expert.
- A new daily puzzle for everyone, and, with Premium, every past daily since 1 January 2026.
- Three free hints a day that explain the next step.
- Challenge a friend with a link to the very same puzzle.
Questions
Does every Sudoku have one solution?
Yes. Every puzzle here has exactly one solution, and you can reach it by logic alone. When you are stuck, a hint names the next step, such as a hidden single or a naked pair, and explains why it works.
Do I need to be good at maths?
No. The digits are only symbols and nothing is added up. You could play the same puzzle with nine letters or nine colours.
What are notes?
Small pencil marks for the digits that could still fit in a square. Switch Notes on, tap a square and pick the digits. They help you spot pairs and other patterns.
Get the app
Download on the App Store (coming soon) Get it on Google Play