How to play sudoku
Fill a 9×9 grid with the digits 1 to 9. The only thing to avoid is repeating a digit.
- each row holds 1 to 9, once each
- each column holds 1 to 9, once each
- each 3×3 box marked off by the heavy lines holds 1 to 9, once each
The digits that were there from the start cannot be changed. There is no arithmetic, and every cell can be worked out without guessing.
If you are new, start here
- Look at the fullest rows and boxes first. With only two or three cells left, the missing digits are quick to place.
- Pick one digit and sweep the grid. If two boxes of a horizontal band already hold a 7, the 7 in the third box can only go in the row that has none.
- When you are not sure, write the possible digits into the cell as notes.
The hints in this game
- Press the hint button and it shows where to look and why, then places the digit.
- It searches thirteen techniques, easiest first. Each one has its own page with an example.
- Auto notes, undo, and highlighting for matching and duplicate digits can be switched on in settings.
- Close the tab and come back — the puzzle you were solving is still there.
Where sudoku came from
The modern form first appeared in a US puzzle magazine in 1979 under the name Number Place. The Japanese publisher Nikoli ran it again in 1984 and gave it the name that means “the digits stay single”. It spread worldwide after a British newspaper began printing it in 2004.
