Basic rules for Sudoku

What is Sudoku?

Sudoku is a puzzle where the game grid needs to be filled with numbers according to the rules. It's important to note that a genuine Sudoku has only one correct solution. Anyone can play Sudoku; there's no need for special mathematical knowledge. All you need is to use your logic and know the rules of Sudoku.

How to play Sudoku?

• Take your time; no one forces you to find the solution as quickly as possible.
• Use only logic; no number guessing allowed.
• Start your game with assumptions for digits that frequently repeat.
• If stuck, try using a different Sudoku-solving method.
• Avoid using hints.
• If you make a mistake, try to find it as soon as possible.
• For difficult Sudokus, use notes.

Classic Sudoku rules (for a 9x9 grid)

Classic Sudoku consists of 9 rows and 9 columns, totaling 81 cells. Additionally, the game grid has 9 squares, each 3x3 in size. Some cells are already filled, and the player needs to fill in the empty ones.

Each row and column must contain unique digits from 1 to 9, and the same applies to each 3x3 square.

Killer Sudoku rules (for a 9x9 grid)

Killer Sudoku is a variation of classic Sudoku, also known as killer su doku, sumdoku, sum doku, sumoku, addoku, or samunamupure. The distinguishing feature is the presence of additional cell groups outlined by dotted lines. Here are the key rules applicable to both beginners and experienced players:

1. Without duplicate digits in one group (marked with dashes).
2. The sum of digits in one group should be equal to the number in the upper left corner of the group.
3. The sum of digits in one column, row, or 3x3 square should be equal to 45.
4. Only digits from 1 to 9 without repetition in rows, columns, and additional areas (3x3 squares).

In some cases, solving Killer Sudoku can be even easier than classic Sudoku. Therefore, we recommend trying both variations on our website.