Sudoku Techniques
Every Sudoku puzzle can be solved with pure logic — no guessing. What matters is knowing which technique to apply when. Below, each one is explained step by step, with examples and the reasoning behind it.
New here? Start with Naked Singles and Hidden Singles. They will get you through any Easy and most Medium puzzles. For a guided walkthrough, read How to Solve Sudoku for Beginners.
Playing Killer Sudoku? See the Killer Sudoku rules and strategies.
Beginner2
Intermediate4
Naked Pairs
Two cells in the same unit sharing exactly two candidates — locked together.
Hidden Pairs
Two digits restricted to exactly two cells in a unit, hidden among other candidates.
Pointing Pairs
When a digit in a 3x3 box can only go in one row or column — it points outward.
Box-Line Reduction
The mirror of Pointing Pairs — when a row or column claims a digit for a single box.
Advanced3
X-Wing
A 2x2 candidate rectangle for one digit — locks two full lines.
Y-Wing
A pivot plus two wings on three digits — the first chain technique.
Swordfish
Coming soonThe X-Wing’s bigger cousin: a six-cell pattern across three rows and columns.