‘Alternate Pair’ Sudoku puzzle solving guide

When you become really stuck the Alternate Pair rule often comes to the rescue.

Other guides available

• Index of available guides
• 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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