Sudoku Tips & Strategies

Ready to take your Sudoku skills to the next level? These tips and strategies will help you solve puzzles faster and tackle more difficult challenges.

Basic Strategies

1. Scanning Technique

Systematically scan rows, columns, and boxes to find cells where only one number can fit. This is the foundation of Sudoku solving.

• Row/Column Scanning: Check each row and column for missing numbers
• Box Scanning: Focus on one 3×3 box at a time
• Number Scanning: Pick a number (like 1) and try to place it everywhere possible

2. Single Candidate (Naked Singles)

When a cell can only contain one possible number, fill it in immediately. This is the most straightforward technique.

3. Single Position (Hidden Singles)

Sometimes a number can only go in one position within a row, column, or box, even if that cell has other candidates. Look for these opportunities.

Intermediate Strategies

4. Candidate Lines

If a number in a box is restricted to a single row or column, you can eliminate that number from the rest of that row or column outside the box.

5. Double Pairs (Naked Pairs)

When two cells in the same row, column, or box can only contain the same two numbers, those numbers can be eliminated from other cells in that unit.

6. Hidden Pairs

When two numbers can only appear in two cells within a row, column, or box, all other candidates can be eliminated from those two cells.

Advanced Strategies

7. X-Wing Pattern

When a candidate appears in only two positions in two different rows (or columns), and these positions line up in columns (or rows), you can eliminate that candidate from other cells in those columns (or rows).

8. Swordfish Pattern

Similar to X-Wing but involves three rows and three columns. This is a more complex pattern that appears in harder puzzles.

9. Y-Wing Pattern

A chain of three cells that share candidates in a specific pattern, allowing you to eliminate candidates from cells that can see both ends of the chain.

General Tips for Success

• Use pencil marks: Note possible candidates in each cell (our game does this automatically)
• Start with constraints: Focus on rows, columns, and boxes with the most filled cells
• One number at a time: Try placing one number across the entire grid before moving to the next
• Look for patterns: The more you play, the more patterns you'll recognize
• Stay organized: Keep track of your logic and reasoning
• Practice regularly: Consistency is key to improvement
• Don't guess: Every move should be based on logic
• Take breaks: If stuck, step away and return with fresh eyes

Difficulty-Specific Tips

Easy Puzzles

Easy puzzles can usually be solved with basic scanning and single candidate techniques. Focus on building speed and accuracy.

Medium Puzzles

Medium puzzles require intermediate strategies like naked pairs and hidden singles. Start incorporating these techniques into your solving process.

Hard Puzzles

Hard puzzles demand advanced strategies and careful analysis. Be patient and methodical—these puzzles reward persistence.

Related Resources

• How to Play Sudoku - Learn the basics
• What is Sudoku? - History and background
• Home - Back to main page