Learn how to solve Sudoku

There are a large number of different forms of Sudoku that have developed over the last few years. Some of them are straightforward twists on the original rules of Sudoku and others have taken a more radical turn.

We have developed a complete set of animated guides to take you through each step of applying all the widely used solution techniques.

Only Choice rule for gentle puzzles
Only Square rule for gentle puzzles
Single Possibility rule for gentle puzzles
Two out of Three strategy for gentle puzzles
Shared Subgroup rule for gentle and moderate puzzles
Naked Twin rule for moderate puzzles
Hidden Twin rule for tough puzzles
X Wing rule for tough puzzles
Swordfish rule for tough puzzles
Alternate Pair rule for very tough puzzles
Hook rule for very tough puzzles
Trial and error rule for any puzzle

Here are some example puzzles that are solved step by step using these strategies.

Gentle puzzle solved using the Two out of Three strategy
Gentle puzzle solved using Only Choice and Only Square
Moderate puzzle solved using some Twin and Sub-group logic
Challenging puzzle solved using Hook and Sub-group logic

Create a new puzzle online or solve a printed puzzle online using our online Sudoku Server. Read more...

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