The Basics
Sudoku is a logic-based number puzzle that has become one of the world's most popular brain games. Despite using numbers, no math is required—only logical deduction and pattern recognition.
The goal is simple: fill a 9×9 grid with digits 1-9 following three basic rules. Each puzzle has a unique solution that can be reached through logic alone—never guessing.
💡 Key Fact
The name "Sudoku" comes from Japanese, meaning "single numbers" (数独, sūdoku). However, the modern puzzle was actually invented by an American architect, Howard Garns, in 1979.
The Three Rules
Every Sudoku puzzle follows exactly three rules:
Each Row Contains 1-9
Every horizontal row must contain each digit from 1 to 9 exactly once. No repetition allowed.
Each Column Contains 1-9
Every vertical column must contain each digit from 1 to 9 exactly once. No repetition allowed.
Each 3×3 Box Contains 1-9
Each of the nine 3×3 sub-grids (boxes) must contain each digit from 1 to 9 exactly once.
✅ Pro Tip
Think of it this way: every row, column, and box is like a container that needs exactly one of each number 1-9. If a number already exists in that container, it can't appear again.
Understanding the Grid
A standard Sudoku grid consists of:
- 81 cells arranged in a 9×9 grid
- 9 rows running horizontally
- 9 columns running vertically
- 9 boxes (3×3 sub-grids) outlined by thicker lines
Blue numbers are given clues; gray numbers are solved by the player
How to Start Solving
Follow these steps when approaching a new puzzle:
- Scan the grid - Look for rows, columns, or boxes that have many given numbers
- Find obvious placements - If a row/column/box is missing only one number, fill it in
- Use elimination - For each empty cell, determine which numbers are possible
- Look for singles - Find cells where only one number can go
- Repeat - Keep scanning and eliminating until the puzzle is complete
Basic Techniques
1. Scanning (Crosshatching)
Look at each number (1-9) and scan where it can go in empty boxes. Use the existing numbers in rows and columns to eliminate possibilities.
2. Naked Singles
When a cell has only one possible candidate after eliminating all numbers that appear in its row, column, and box, that candidate must go there.
3. Hidden Singles
When a number can only go in one cell within a row, column, or box—even if that cell has other candidates—that number must go there.
Tips for Beginners
✅ Do's
• Start with easy puzzles and gradually increase difficulty
• Use pencil marks to note possible candidates
• Take breaks when stuck—fresh eyes help
• Double-check each number placement
⚠️ Don'ts
• Never guess—Sudoku is pure logic
• Don't place a number unless you're 100% sure
• Avoid the temptation to look at solutions
• Don't give up—every puzzle has a solution
Frequently Asked Questions
Do I need to be good at math?
No! Sudoku uses numbers as symbols, but requires no mathematical calculations. You could use letters, colors, or shapes instead.
Can a Sudoku puzzle have multiple solutions?
A properly constructed Sudoku puzzle has exactly one unique solution. If a puzzle has multiple solutions, it's considered flawed.
Is guessing ever necessary?
Never. Every valid Sudoku puzzle can be solved through pure logic. If you feel the need to guess, you may have missed a logical deduction.
como se juega el sudoku
print Common Sudoku Mistakes and How to Avoid Them

print Advanced Sudoku Solving Techniques

print Basic Sudoku Rules for Beginners

print Sudoku Strategies: Scanning and Marking

print Sudoku Strategies: Scanning and Marking

print The Benefits of Playing Sudoku Daily

print Common Sudoku Mistakes and How to Avoid Them

🔍 Related Searches
-
sudoku xy wing
printable beginner sudoku
sudoku for 4th graders
new york post sudoku hard
mathsphere sudoku
daily sudoku by krazydad
sudoku print outs
sudoku solving techniques
is sudoku good for the brain
sudoku puzzles download
sudoku addition
sudoku rules simple
sudoku for money
sudoku completer
sudoku expert tips
best sudoku app iphone
janric sudoku
best sudoku strategy
x wing sudoku explained
mega sudoku 16x16