# ‘Hidden Twin’ Sudoku puzzle solving guide

When you get stuck with a puzzle, looking for twins (and triplets) can be a good source of new squares to solve.

- Index of available guides
- Running a Tutorial
- Choosing a Tutorial
- 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
- Solving a gentle puzzle step by step
- 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

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