Sudoku Rules and How to Play - Complete Guide

Want to learn how to play sudoku? You've come to the right place. This guide covers everything you need to know, from the basic rules to advanced strategies. Whether you're a complete beginner or looking to improve your skills, we'll walk you through how to fill a 9×9 grid so that every row, column, and 3×3 box contains the digits 1 through 9 exactly once.

The Basic Rules of Sudoku

Sudoku is played on a 9×9 grid that's divided into nine smaller 3×3 boxes. Your goal is simple: fill the entire grid with numbers 1 through 9, making sure that:

  • Every row contains all digits 1-9 with no repeats
  • Every column contains all digits 1-9 with no repeats
  • Every 3×3 box contains all digits 1-9 with no repeats

How to Solve a Sudoku Puzzle

Here's a step-by-step approach to solving sudoku puzzles:

Start by Looking at What's Already There Take a good look at the numbers that are already filled in. Rows, columns, or boxes that have 6 or 7 numbers are your best starting points—they give you the most clues about what's missing.

Use Logic to Find Possibilities For each empty cell, figure out which numbers could possibly go there by looking at what's already in that row, column, and 3×3 box. Any number that's already used in any of those three areas is automatically eliminated.

Fill in the Obvious Ones First When you find a cell that can only contain one number, fill it in. Each new number you place gives you more information, which helps you solve more cells. Keep repeating this process until the grid is complete.

Common Mistakes to Avoid

Here are the most common mistakes people make when solving sudoku:

  • Putting a number in a cell when that number already exists in the same row, column, or box
  • Guessing instead of using logic—sudoku is all about deduction, not luck
  • Only checking the row or column but forgetting to check the 3×3 box (or vice versa)

Tips for Better Solving

Here are some practical tips that will help you solve sudoku puzzles more effectively:

Look for the Easy Wins First Start by finding cells where only one number is possible. These are usually in rows, columns, or boxes that are almost complete. Getting these quick wins gives you momentum and more clues to work with.

Use the Process of Elimination For each empty cell, think through which numbers could go there. Then eliminate any numbers that are already used in that cell's row, column, or box. What's left is your answer.

Work Systematically but Stay Flexible It helps to focus on one area at a time, but don't be afraid to switch when you get stuck. Sometimes solving a cell in one part of the grid suddenly opens up possibilities in a completely different area.