Duplicate of a Kept Cell
Easy
Used by Smart Hint
Once a cell is kept, its number can't repeat among kept cells — every other copy in that row and column is rejected.
- Kept
- Rejected
- Cells that establish the pattern
- Where the conclusion lands
How it works
- The top-left 5 is already known to be kept.
- Its number can't repeat among kept cells in the same row or column, so the other 5 in the top row must be rejected.