Hidden Quad
A Hidden Quad is a Hidden Subset of size 4.
When all candidates for 4 digits in a house are limited to only 4 cells, these cells must contain these 4 digits. Subsequently, all remaining candidates can be removed from these 4 cells.
Example
The following example shows a Hidden Quad in the 6th box.
Sudoku Games
- Sudoku 9981
- Samurai Sudoku
- Sudoku Printer
- Word Sudoku to Learn English
Word Sudoku to Learn Chinese
Word Sudoku to Learn French
Word Sudoku to Learn German
Word Sudoku to Learn Spanish
Free Sudoku Script for Your Website
Sudoku strategies
- Coloring
- Singles
- Fish
- Chains and Loops
- Intersections
- Subsets
- Wings
- Single Digit Patterns
- Uniqueness
- Almost Locked Sets
