Practise: Unique Rectangle Type 2
Find the two exact-pair floor corners. The other two corners must be adjacent, share a row or column, and each have exactly the same single extra candidate. Inspect only cells that see both roofs; those are the safe targets for the shared extra digit.
You are at the verified key position. Use a hint to follow the chain link by link when you need support.
Your turn first
Spot the idea before the hint explains it
- 1. Look
- 2. Check
- 3. Proof
Look at the marked starting cells and their candidates. Which digit or candidate relation is forced, and what visible row, column or box fact supports your idea?
How to spot it
Find the two exact-pair floor corners. The other two corners must be adjacent, share a row or column, and each have exactly the same single extra candidate. Inspect only cells that see both roofs; those are the safe targets for the shared extra digit.
Put it to use
Where you will meet it
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