Sudoku Rules & Solving Techniques
Master Sudoku with our comprehensive guide to rules and solving strategies. From basic rules to advanced techniques used by experts.
Basic Rules
How to Play Sudoku
- 1 Fill the 9×9 grid with numbers 1-9
- 2 Each row must contain all digits 1-9
- 3 Each column must contain all digits 1-9
- 4 Each 3×3 box must contain all digits 1-9
Example: Find the missing numbers in this 3×3 box
Solving Techniques
Beginner Essential Techniques
Obvious Singles
Find cells where only one number can fit based on row, column, and box constraints.
Learn technique →Last Free Cell
Fill the final empty cell in a row, column, or 3×3 box with the missing number.
Learn technique →Last Remaining Cell
Identify the last possible position for a specific number in a region.
Learn technique →Last Possible Number
Find cells where elimination leaves only one possible number.
Learn technique →Hidden Singles
Discover numbers that can only go in one cell within a row, column, or box.
Learn technique →Intermediate Pattern Recognition
Obvious Pairs
Two cells in the same region that can only contain the same two numbers.
Learn technique →Obvious Triples
Three cells that can only contain the same three numbers between them.
Learn technique →Hidden Pairs
Two numbers that can only appear in two specific cells within a region.
Learn technique →Hidden Triples
Three numbers that can only appear in three specific cells within a region.
Learn technique →Pointing Pairs
Use box-line interactions to eliminate candidates in rows and columns.
Learn technique →Pointing Triples
Extended pointing pairs technique with three cells pointing to eliminate candidates.
Learn technique →Box/Line Reduction
Eliminate candidates when all instances of a number in a line are confined to one box.
Learn technique →Advanced Complex Patterns
Ready to Practice?
Now that you know the techniques, put them to practice with our free online Sudoku game!