Beginner Guide
Sudoku Rules – How to Play with Interactive Examples
Sudoku is a logical number puzzle played on a 9×9 grid (81 cells). Despite millions of possible configurations, every puzzle on SudoLoom revolves around 3 golden rules below.
Rule 1: Horizontal Rows
Each of the 9 horizontal rows must contain all digits from 1 to 9 without repeating any number.
Rule 2: Vertical Columns
Each of the 9 vertical columns must also contain every digit from 1 to 9 with no duplicates.
Rule 3: 3×3 Boxes
The grid is divided into nine 3×3 sub-boxes. Each 3×3 box must also contain every digit from 1 to 9.
Practice 1: No Duplicates in a Row
5
3
1
9
?
7
2
8
6
Click a digit below to fill the highlighted teal cell in Row 1.
Practice 2: The 3×3 Box Rule
1
8
4
2
?
9
6
5
3
Every 3×3 box (outlined by bold borders) must also contain all digits from 1 to 9. Try picking the missing number for the center cell:
You’ve mastered the 3 core rules! Start right away with an Easy puzzle:
Play Easy Sudoku Now