How to Solve Sudoku: Beginner to Expert Guide

What Is Sudoku?

Sudoku is a logic puzzle where you fill a 9x9 grid with the numbers 1 through 9. Every row, every column, and every 3x3 box must contain each number from 1 to 9 exactly once.

Basic Techniques

1. Scanning

The simplest technique: pick a number (say, 1) and check where it can be placed across the entire grid. Existing numbers in each row and column narrow down the possible locations.

2. Naked Single

If only one number is possible in a given cell, that number goes there. Eliminate all numbers that already appear in the cell's row, column, and box -- if only one candidate remains, that's your answer.

3. Hidden Single

If a number can only go in one cell within a row, column, or box, it must go there -- even if that cell has other candidates.

Intermediate Techniques

Naked Pairs

If two cells in the same row, column, or box share the same two candidates (and only those two), those two numbers can be eliminated from all other cells in that group.

Pencil Marks

For harder puzzles, write small candidate numbers in each cell. This makes patterns much easier to spot. Our Sudoku game has a built-in "Notes" mode that does exactly this!

Tips for Success

• Start with easy puzzles and gradually expand your technique repertoire
• Never guess -- Sudoku is a pure logic game
• Begin with the row, column, or box that has the most given numbers
• Practice regularly -- speed comes with time