What is Sudoku?
Sudoku is a logic-based number puzzle that has captivated millions of people worldwide. Despite using numbers 1-9, it requires no math skills — just pure logical thinking and patience!
The goal is simple: Fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 boxes contains all digits from 1 to 9, without repetition.
🎯 The Golden Promise
Every properly constructed Sudoku puzzle has exactly one solution. You never need to guess — every cell can be solved through pure logic!
The Three Simple Rules
Sudoku has only three rules, and they're beautifully simple:
Row Rule
Each row must contain the numbers 1-9 exactly once
Column Rule
Each column must contain the numbers 1-9 exactly once
Box Rule
Each 3×3 box must contain the numbers 1-9 exactly once
That's it! These three rules are all you need to know. The challenge comes from figuring out which number goes where.
Understanding the Grid
Explore the Sudoku grid! Click on any cell to see which row, column, and box it belongs to.
💡 What you're seeing:
Click "Explore Grid" to see how rows, columns, and boxes work. Each cell belongs to exactly one row, one column, and one 3×3 box.
How to Approach a Sudoku Puzzle
Step 1: Scan the Puzzle
Start by looking at the numbers already given. These are called "givens" — they're your clues! Notice which numbers appear most often and which rows/columns have the most clues.
Step 2: Eliminate Impossible Numbers
For any empty cell, ask yourself: "Which numbers cannot go here?" Look at the row, column, and box to eliminate candidates.
Step 3: Place Certain Numbers
When a cell has only one possible number, place it! This is called a "Naked Single" — the most basic solving technique.
Step 4: Repeat
Each number you place gives you more information. Keep scanning and eliminating until the puzzle is complete!
Watch: Solving Step by Step
Watch how an easy puzzle is solved using basic logic. Follow along to understand the thinking process!
🧠 Solving Logic:
Each move is made with absolute certainty — no guessing required! Watch how we systematically find the only possible number for each cell.
Essential Tips for Beginners
-
Use Pencil Marks Write small candidate numbers in cells when you're unsure. This helps you visualize possibilities.
-
Start with Busy Areas Focus on rows, columns, or boxes that already have many numbers filled in — they're easier to complete!
-
Look for Unique Positions Ask "Where can this number go?" If it can only go in one place in a row/column/box, that's your answer!
-
Never Guess If you're guessing, stop! Every cell in a proper Sudoku can be solved through logic alone.
-
Take Breaks Stuck? Take a short break. Fresh eyes often spot what tired eyes miss!
Try It Yourself!
Now it's your turn! This very easy puzzle has only a few cells to fill. Click a cell, then click a number to place it.
🎮 Your Turn:
Click on an empty cell to select it, then use the number pad to fill it in. Can you complete the puzzle?
What's Next?
Congratulations on taking your first steps into the world of Sudoku! 🎉
As you get comfortable with basic puzzles, you'll naturally discover more advanced techniques:
-
Naked Singles When a cell has only one possible candidate remaining.
-
Hidden Singles When a number can only go in one place within a row, column, or box.
Ready to Practice?
Start with our beginner-friendly puzzle books, featuring step-by-step solutions for every puzzle!
📚 Browse Our Books📚 Continue Learning
Explore the next best Sudoku guides based on this article.
How to Use Pencil Marks Effectively
Master the art of candidates notation - the essential skill that separates guessing from logical solving....
Naked Single Technique in Sudoku
Master the most intuitive Sudoku technique. Learn to find cells with only one possible candidate - the fo...
Hidden Single Technique in Sudoku
Discover the art of finding hidden singles in Sudoku. When a digit can only go in one place within a row,...