Sudoku technique library

Learn Sudoku techniques one pattern at a time.

Start with basic singles, then build toward candidate patterns like Naked Pair, Hidden Pair, and X-Wing.

Beginner

Learn the Single Candidate Sudoku technique: when one cell has only one possible number left.

Learn the Hidden Single Sudoku technique: when a number has only one possible position in a row, column, or box.

Learn how Naked Pairs work in Sudoku, when to look for them, and how to remove candidates safely.

Learn how Hidden Pairs work in Sudoku, why they are harder to see than Naked Pairs, and how to clean up candidates.

Learn the X-Wing Sudoku technique with a simple candidate pattern, clear elimination rule, and practice-focused explanation.

Technique pages explain the pattern. Sudoku Coach helps you recognize it on real boards.