How to Solve a Sudoku

Sudoku is a puzzle game with three simple rules. A Sudoku square has nine rows and nine columns, and is further divided into nine sub-squares with nine individual boxes. To solve a Sudoku, each row, column and sub-square must contain the numbers 1 through 9 without repeating any number within any rows, columns or sub-squares. It’s a challenge at first, so use these tips to get you started.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Puzzle book
• Pencil

1. Start by looking for patterns that leave only one possible correct placement of a number. Take a few seconds to scan the whole Sudoku square and plan a few scenarios.

2. Focus on one number at a time for each of the major segments of the Sudoku square. Divide the sub-squares into groups and assess the possibilities for a number.

3. Use the numbers you fill in to lead to additional successful answers. When you fill in one number it affects the placement of the number in other rows and columns.

4. Focus on sub-squares that only have three boxes left to fill. Use the columns and rows that compose the sub-square to try to eliminate some possibilities.
   

5. Note what numbers are missing from a sub-square and find where those numbers are located in the columns and rows that compose the sub-square. If a missing number is in two out of the three rows or columns comprising the sub-square, then this tells you where the number should go.

6. Write down the numbers missing from a sub-square next to the Sudoku square. Note the possible locations of each number. This may help you eliminate some choices and enable you to place a number without seeing that number in any of the columns or rows that compose the sub-square.

7. Mark potential correct locations for a number around the edges of the box. Write them smaller than you would normally write the correct answer.

Tips & Warnings

• Use a pencil or erasable pen when doing a Sudoku puzzle.
• Sudoku puzzles are offered on a number of Web sites to play for free. You can also download more complex versions of Sudoku (see Resources below).
• Don’t make too many markings for potential correct spots for numbers. It is easy to make a mess and get confused.