Select Challenge Level

Test your logical reasoning limits

Hard

Suitable for experienced players

28-32 clues

Extreme

The real challenge begins

22-27 clues

Nightmare

Only top players can complete

17-21 clues

Diabolical

Requires advanced techniques

Under 17 clues

Expert Tips

  • Use candidate number marking
  • Hidden singles
  • Apply X-Wing and Swordfish techniques
  • Use chain reasoning

Game Variants

Classic Sudoku

Standard 9x9 Sudoku

Diagonal Sudoku

Diagonals cannot repeat

Irregular Sudoku

Non-standard box shapes

Features

Smart Hints

Intelligent hint system helps you solve puzzles step by step

Leaderboards

Compete with global players and showcase your Sudoku skills

Real-time Timer

Precise timing to challenge your solving speed

Responsive Design

Perfect adaptation to all devices, play anytime, anywhere

Sudoku Mode Introduction

Easy Mode

Perfect for beginners to learn Sudoku basics

Hard Mode

Challenge advanced skills and logical thinking

Diabolical Mode

Ultimate challenge for the highest skill level

Hell Mode

Final difficulty, only for true Sudoku masters

How to Solve Evil Sudoku

Master advanced Sudoku techniques to conquer the most challenging puzzles

Core Advanced Techniques

Naked Singles Method

When a cell has only one possible number, fill it immediately. This is the foundation of all Sudoku solving.

Hidden Singles Method

When a number can only go in one position within a row, column, or box, fill it even if the cell has multiple candidates.

Naked Pairs Elimination

When two cells in the same region contain the same two candidate numbers, eliminate those numbers from other cells.

X-Wing Technique

When a candidate appears in exactly two positions in two parallel rows (or columns), powerful eliminations can be made.

Solving Steps

  1. Scan for Obvious Numbers

    Start by filling in all naked singles and hidden singles to create a foundation for advanced techniques.

  2. Mark Candidate Numbers

    Mark all possible values in empty cells. This visualization is crucial for spotting patterns.

  3. Apply Elimination Techniques

    Use naked pairs, pointing pairs systematically to eliminate impossible candidates.

  4. Look for Advanced Patterns

    When basic techniques stall, search for X-Wing, Swordfish and other complex patterns to break through.

Pro Tips

Pattern Recognition

Train your eye to quickly spot common patterns. The more patterns you recognize, the faster you solve.

Take Breaks

When stuck, step away for a few minutes. Fresh eyes often spot solutions not visible before.

Use Pencil Marks

Always maintain accurate candidate lists. Clean, organized notes are essential for advanced techniques.

Practice Daily

Consistent practice builds pattern recognition and technique mastery. Start easy and gradually increase difficulty.

Ready to Test Your Skills?

Apply these techniques in our challenging evil-level Sudoku puzzles