Hard Sudoku
Welcome to Hard Sudoku, where puzzles demand advanced solving techniques and strategic thinking. This difficulty level is designed for experienced solvers who enjoy complex logical challenges and sophisticated solving patterns.
Techniques You'll Need
- XY-Wing and XYZ-Wing
Advanced chain techniques where a pivot cell with 2-3 candidates connects to cells sharing candidates, allowing for eliminations
- Unique Rectangles
Avoiding deadly patterns that would create multiple solutions by forcing specific placements
- Naked and Hidden Quads
When four cells in a unit contain only the same four candidates, those candidates can be eliminated from other cells
- Jellyfish
An extension of X-Wing and Swordfish involving four rows and four columns, creating powerful elimination patterns
Advanced Challenge
These puzzles require careful analysis and the ability to spot complex patterns. You'll need to master multiple advanced techniques and often combine them in creative ways. Hard mode is where casual solving transforms into strategic problem-solving, requiring patience and methodical thinking.