Mirrored from Sudopedia, the Free Sudoku Reference Guide
A digit is restricted common to 2 Almost Locked Sets when it cannot be present in both sets at the same time.
As a result, one of the sets must be locked for the remaining digits. This result is used in the ALS-XZ and ALS-XY-Wing techniques.
This page was last modified 22:22, 18 November 2007.