📐 Sudoku Solving Patterns – Identify & Apply Techniques

Learn to spot and leverage powerful Sudoku patterns such as X-Wing, Skyscraper, and Jellyfish. These patterns help you eliminate candidates efficiently and solve complex puzzles faster.

🎯 What Are Sudoku Patterns?

Sudoku patterns refer to recurring structures or arrangements in the puzzle grid that allow solvers to eliminate candidates or place numbers logically. Recognizing patterns helps streamline solving without guessing, especially in high-difficulty puzzles.

🔷 Most Useful Sudoku Patterns

1. X-Wing

This pattern appears when a candidate appears in exactly two cells in two separate rows and the same columns. It allows you to eliminate that candidate from the rest of the columns.

2. Swordfish

A more complex form of X-Wing involving three rows and three columns. If the candidate exists only in three matching columns across those rows, you can eliminate it from all other cells in those columns.

3. Skyscraper

This advanced technique uses a pair of rows (or columns) with two candidates each. It helps eliminate candidates diagonally from common affected units.

4. XY-Wing

In this structure, you identify three cells (X–Y, Y–Z, and X–Z) that share candidates in a specific way. If set up correctly, you can eliminate the Z candidate from cells seeing both outer cells.

5. Jellyfish

A rare but powerful pattern involving four rows and four columns. The candidate appears exactly four times, enabling eliminations similar to Swordfish but across a larger scope.

6. Empty Rectangle

This subtle pattern helps eliminate candidates by identifying rectangles that contain certain restrictions. It’s a valuable tool for tricky eliminations in hard puzzles.

🧠 When to Use Patterns

• When standard techniques (naked/hidden singles or pairs) no longer yield results.
• When you're tackling levels 12 and above on Sudoku99 or puzzles with fewer than 25 clues.
• As a methodical way to break deadlocks without guessing.

📘 Example Puzzle with Pattern

💡 Tips for Mastering Patterns

• Use pencil marks to visualize candidate placements clearly.
• Study each pattern type with examples before applying in real puzzles.
• Try solving past Level 15 puzzles on Sudoku99 to practice spotting patterns under pressure.

📚 Learn More

• ← Back to Advanced Techniques
• → Go to Daily Pattern Practice