Aligned Quadruple Exclusion
Check candidate combinations in four interacting cells and eliminate candidates absent from every valid combination.
All candidates have been entered in the empty cells.
Assign one candidate to each of cell A, cell B, cell C, cell D. All 32 combinations containing 7 in cell D, 9 in cell D either repeat a digit or empty another cell, as shown below. Remove 7 from cell D. Remove 9 from cell D.