How to Play Sudoku

Sudoku is one of the most popular logic games of all time. The object of the game is to fill a 9×9 grid with numbers: Each row, column and smaller 3×3 section must contain all numbers from 1 to 9.

What is Sudoku?

Sudoku is an excellent game to train your brain, because it requires logical thinking and a keen eye for details. It's a fun and useful way to spend your free time or improve your logical skills. You can play Sudoku games online 24/7 on your computer or phone. Try them now and enjoy the exciting challenge.

On our website Play123, all Sudoku games are free to play. You can try different difficulty levels, from easy to very challenging: once you have mastered the easy level, you can move on to the medium level and Sudoku Puzzles will present you with new challenges. Some games even offer the possibility of saving your progress and checking the solutions. In the Ultimate Sudoku game you'll also be able to save your score and track your progress over time.

How to play Sudoku?

Sudoku grid

We play Sudoku on a 9x9 grid. [source]

The object of the game is to fill a 9x9 grid. Each column, row and 3x3 section must contain the numbers from 1 to 9.

Start with a smaller 3x3 section of the grid and look for numbers that are already filled in (at the beginning of the game there are only a few filled squares or cells in the grid).

Your task is to fill in the missing numbers with logic and complete the grid to the end.

Sudoku rules

A move in Sudoku is considered correct if it satisfies the following two conditions::

  • the number mustn't occur in the same row, column, or 3x3 section
  • the number must comply with the rule that each row, column and 3x3 square should contain all numbers from 1 to 9 exactly once

A move is considered incorrect if:

  • any row contains duplicate numbers from 1 to 9
  • any column contains duplicate numbers from 1 to 9
  • any 3x3 section contains duplicate numbers from 1 to 9

Sudoku for beginners

We have prepared a simple educational game for beginners - or Sudoku for kids - that will help you quickly grasp the rules and logic of Sudoku. More experienced users can skip this game and move on to more challenging puzzles.

Click on an empty cell and enter the missing number:

Why is Sudoku so popular?

The number puzzle Sudoku has gained popularity due to its easy to understand game principle and complexity at the same time. On our website you can find many games with different levels of difficulty, which will provide you with a useful pastime on a rainy Sunday. Besides having fun with the game, you can also improve your mental abilities and keep yourself mentally fit in a fun way

Unlock the Secrets of Sudoku

Tip #1: The First Step

Start with easy numbers: look for the numbers that have only one possible position in the row, column, or 3x3 section.

Tip #2: Eliminating Numbers

Use the elimination rule: if a number appears in a row, column, or 3x3 section, you can eliminate it from the other cells in the same row, column, or 3x3 section.

Tip #3: Looking for Pairs

If two cells in the same row, column, or 3x3 section have only two possible numbers, then those two numbers form a pair and can be eliminated from the other cells in the same row, column, or 3x3 grid.

Tip #4: Write down the candidates

Use the good old pen and paper method. Write down the possible candidates for each cell in small numbers. That way you can rule out options and see patterns.

Tip #5: Advanced Techniques

There are various techniques for solving Sudoku, such as hidden pairs, triples, and quads, x-wing, swordfish, and others. You can learn these techniques on various Sudoku-related websites.

Sudoku FAQ

Who invented Sudoku?

Sudoku, sometimes also called suduko or soduku, did not originate in Asia as many people think. The beginnings of the game date back to 19th century France when magic squares were published in newspapers. However, these were not quite the same Sudoku Puzzles we know today, as they contained two-digit numbers. The Sudoku game principle, designed by puzzle creator Howard Garns, was published in 1979 as "Number Place" in New York puzzle booklets [source].

What does Sudoku mean?

In 1984, the game was introduced in Japan and named Sudoku there. Sudoku is a Japanese word that means single number or number alone.

Is the online Sudoku different from the paper version?

The rules of the digital version of the game are no different from the paper version. However, for our online game you don't need a pencil or an eraser. Just click on an empty field and select the number you want. If you make a mistake, you can easily remove the number you just placed and replace it with another one.

Can I print Sudoku on paper?

If you prefer the old-fashioned method of solving Sudoku puzzles with pen and paper, you're in luck! On our website you can find printable Sudoku puzzles and solve them at your leisure, try our Daily Sudoku X, which also includes a diagonal constraint in addition to the standard Sudoku rules. With a print option and a variety of puzzle options, you can enjoy the classic Sudoku experience easily.