How to play Sudoku: rules and solving tips
Also known as: Number Place, سودوکو
Sudoku rules explained step by step, with beginner and advanced solving methods. Learn to fill the 9x9 grid using logic only, without any guessing.
- Type
- Folk game
- Players
- 1
- Age
- Ages 8+
- Origin
- Published as Number Place in the United States; named Sudoku in Japan
Sudoku is a logic puzzle played on a grid of nine rows and nine columns, divided into nine smaller boxes of three by three. Some squares already contain digits, and the solver must fill the rest so that every row, column and box contains each digit from 1 to 9 exactly once. The modern form first appeared in American puzzle magazines under the name Number Place, and it became famous after a Japanese publisher gave it the name Sudoku. In the 2000s it spread to newspapers around the world. Although it uses numbers, Sudoku needs no arithmetic at all: the digits are only symbols. What it needs is patience, careful observation and step-by-step reasoning, which is why many people use it as daily exercise for the mind.
Our verdict
Sudoku gives a clean, quiet challenge that needs only a pencil or a screen. Each puzzle has one correct answer, so you always know when you have succeeded. Difficulty levels range from gentle to extremely hard, and the same rules carry you through all of them. It is a good habit for practising concentration and ordered thinking, and because it uses no words, it works the same in every language. A single puzzle can take five minutes or an hour, which makes it easy to fit into travel or a short break.
What works
- Needs no special equipment
- Clear difficulty levels for every skill
- No language or maths knowledge required
What does not
- A single mistake can spoil a whole grid
- Purely solo, with little social element
How to play Sudoku
Start with a puzzle that has some digits already given. Your task is to place a digit from 1 to 9 in every empty square. There are three rules, and they apply at the same time: each row must contain all nine digits once, each column must contain all nine digits once, and each three-by-three box must contain all nine digits once. A well-made puzzle has exactly one solution, and it can always be reached by logic. A good first method is scanning: choose a digit, look at where it already appears, and find the box where only one square is still possible for it. A second method is to look at a single square and remove every digit already used in its row, column and box. If only one candidate remains, write it in. Many solvers write small pencil marks of possible candidates in each square and remove them as the grid fills up.
Tips for new players
- Begin with digits that already appear many times in the grid; they usually have the fewest open places.
- Use small pencil marks for candidates, and update them each time you place a digit.
- Look for pairs: if two squares in a row can only hold the same two digits, those digits can be removed from the rest of that row.
- Never guess. If you feel stuck, scan every row, column and box again for a single forced square.
Good for
Sudoku: common questions
Do you need to be good at maths to play Sudoku?
No. Sudoku uses digits only as symbols. You could replace them with letters or colours and the puzzle would work the same way.
How many solutions does a Sudoku have?
A properly made Sudoku has exactly one solution, and it can be found by logic without guessing.
What is the best way to start a Sudoku?
Scan for the digits that already appear most often and look for boxes where that digit has only one possible square.
Sudoku belongs to its owners. Playdonya is not connected to them and does not sell this game; the cover is our own illustration.
