Sudoku Solving Techniques

Techniques are recurring ways of reading the grid: patterns that let you place a digit or eliminate candidates by pure deduction. They're also how difficulty is measured here: every puzzle is graded by the techniques it requires, from easy to expert.

Each guide explains one technique step by step, with a diagram and the most common mistakes:

• Naked Pairs — two cells, two candidates: the first elimination technique, and the doorway to the medium level.
• Pointing Pairs — when a box pins a row or column, and sweeps it clean.
• X-Wing — the rectangle that spans the grid, signature pattern of the hard level.

More guides are on the way, one for every technique in the repertoire. If you're starting from the basics instead, begin with how to play and put it into practice on an easy sudoku.