Home › Guides › Sudoku Rules

sudoku premium

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:

1

Each Row Contains 1-9

Every horizontal row must contain each digit from 1 to 9 exactly once. No repetition allowed.

2

Each Column Contains 1-9

Every vertical column must contain each digit from 1 to 9 exactly once. No repetition allowed.

3

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
534678912 672195348 198342567 859761423 426853791 713924856 961537284 287419635 345286179

Blue numbers are given clues; gray numbers are solved by the player

How to Start Solving

Follow these steps when approaching a new puzzle:

  1. Scan the grid - Look for rows, columns, or boxes that have many given numbers
  2. Find obvious placements - If a row/column/box is missing only one number, fill it in
  3. Use elimination - For each empty cell, determine which numbers are possible
  4. Look for singles - Find cells where only one number can go
  5. 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.

king classic sudoku answers today pdf

how to solve a sudoku puzzle hard The rules of Sudoku are simple but the depth of the game is immense. Every well-posed Sudoku puzzle has a unique solution that can be reached through logical deduction. 4x4 sudoku printable Modern Sudoku was popularized by Nikoli in Japan in the 1980s. It has since become a global phenomenon, with daily puzzles appearing in newspapers and online platforms worldwide.

how to solve a sudoku puzzle hard History of the Sudoku Puzzle

latimes sudoku

how to solve a sudoku puzzle hard Many people enjoy solving Sudoku as a relaxing hobby. It provides a sense of accomplishment when a difficult puzzle is finally completed correctly. sudoku medium nyt To solve a Sudoku puzzle, one must look for cells where only one number is possible, or rows/columns/blocks where a specific number has only one possible placement.

how to solve a sudoku puzzle hard Tips for Improving Your Sudoku Speed

expert sudoku techniques

how to solve a sudoku puzzle hard Playing Sudoku daily has many cognitive benefits, including improving memory, concentration, and logical reasoning skills. It is a great way to keep the brain active and healthy. sudoku en ligne Many people enjoy solving Sudoku as a relaxing hobby. It provides a sense of accomplishment when a difficult puzzle is finally completed correctly. naked pair sudoku Many people enjoy solving Sudoku as a relaxing hobby. It provides a sense of accomplishment when a difficult puzzle is finally completed correctly.

how to solve a sudoku puzzle hard Advanced Sudoku Solving Techniques

sudoku joy

how to solve a sudoku puzzle hard To solve a Sudoku puzzle, one must look for cells where only one number is possible, or rows/columns/blocks where a specific number has only one possible placement. samurai sudoku free printable Modern Sudoku was popularized by Nikoli in Japan in the 1980s. It has since become a global phenomenon, with daily puzzles appearing in newspapers and online platforms worldwide.

how to solve a sudoku puzzle hard History of the Sudoku Puzzle

triple sudoku

how to solve a sudoku puzzle hard Advanced Sudoku solving methods involve complex patterns like X-Wing, Swordfish, and XY-Wing. These techniques are often required for hard and expert level puzzles. simple sudoku printable Many people enjoy solving Sudoku as a relaxing hobby. It provides a sense of accomplishment when a difficult puzzle is finally completed correctly.

how to solve a sudoku puzzle hard The Benefits of Playing Sudoku Daily

sudoku blank

how to solve a sudoku puzzle hard Advanced Sudoku solving methods involve complex patterns like X-Wing, Swordfish, and XY-Wing. These techniques are often required for hard and expert level puzzles. pointing pairs sudoku To solve a Sudoku puzzle, one must look for cells where only one number is possible, or rows/columns/blocks where a specific number has only one possible placement.

how to solve a sudoku puzzle hard Basic Sudoku Rules for Beginners

blank printable sudoku

how to solve a sudoku puzzle hard Playing Sudoku daily has many cognitive benefits, including improving memory, concentration, and logical reasoning skills. It is a great way to keep the brain active and healthy. game like sudoku Sudoku variants like Killer Sudoku, Jigsaw Sudoku, and Sudoku-X provide additional challenges for players looking for something different from the classic version. sudoku creator Sudoku variants like Killer Sudoku, Jigsaw Sudoku, and Sudoku-X provide additional challenges for players looking for something different from the classic version. sudoku creator Sudoku variants like Killer Sudoku, Jigsaw Sudoku, and Sudoku-X provide additional challenges for players looking for something different from the classic version. 5 by 5 sudoku Advanced Sudoku solving methods involve complex patterns like X-Wing, Swordfish, and XY-Wing. These techniques are often required for hard and expert level puzzles.

Related Topics

sudoku tournaments how to solve sudoku step by step sudoku program in python how to play sudoku for beginners pdf free sudoku games no download sudoku usatoday

🔍 Related Searches

dell sudoku books welcome to killer sudoku online daily samurai sudoku answer key to sudoku puzzles guardian uk sudoku 3-Link Fish Strategy Play Easy Killer Free Sudoku Game Basic Sudoku Killer Sudoku Tips Beginner Sudoku Tip Standard Sudoku