Sudoku FlowSudoku technique lessons / Unique Rectangle
Lesson 29
Unique Rectangle
The rule
The puzzle has a single solution, so a pattern that would allow two solutions must be avoided.
Step by step
- These four cells form a rectangle in exactly two boxes, and each contains the candidates 3 and 7. If all four were limited to only those two candidates, they would form a deadly pattern.
- To avoid two solutions, the candidates 3 and 7 can be removed from the cell with extra candidates.
Try it on more boards
Each board is a real puzzle from our app, at a moment where Unique Rectangle applies. Find the step yourself, or tap Hint and the app's own hint walks you through it.
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