Block Line
If a value can exist in only one row or column within a block, then the value cannot lie anywhere else in that row or column outside of that block.
Consider the sudoku below.
In the center block, the candidate 8 only exists in r4c5 and r5c5. Regardless of which cell the value 8 is in, we know there cannot be another 8 that exists in column 5. So we can remove the candidate 8 from the cells in column 5 that are outside the center block.
If a value can exist in only one row or column within a block, then the value cannot lie anywhere else in that row or column outside of that block.
Consider the sudoku below.
| 1 |
|
4 | |||||||||||||||
| 2 |
|
5 | |||||||||||||||
| 8 | |||||||||||||||||
In the center block, the candidate 8 only exists in r4c5 and r5c5. Regardless of which cell the value 8 is in, we know there cannot be another 8 that exists in column 5. So we can remove the candidate 8 from the cells in column 5 that are outside the center block.
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Last Updated: CST
Last Updated: CST