Law of Leftover
Use the matching sets of digits left outside a line-block intersection to narrow candidates.
All candidates have been entered in the empty cells.
column A and block B share the same three-cell overlap. column A and block B each contain the digits 1 through 9 once. The six cells only in column A and the six cells only in block B are both filled by 2, 3, 4, 5, 7 and 9. Candidates 1, 6 and 8 marked × can be removed.