Finned Swordfish

A Finned Swordfish occurs when there is a Swordfish with additional candidates.

In the sudoku diagram below either in the R1C6 cell (marked in yellow) the digit 2 can be placed or we have a Swordfish, i.e. in the first, seventh and ninth rows the digit 2 can only be placed in the second, fourth and ninth columns (candidates marked in blue). Thus, we can eliminate the digit 2 from the other cells of these columns, which simultaneously see the cell R1C6, and therefore from the cell R3C4. After applying this elimination, only the digit 4 can be placed in the R3C4 cell.



In turn, in the sudoku diagram below either in the R8C1 cell (marked in yellow) you can place the digit 9 or we have a Swordfish, i.e. in the second, fifth and eighth rows the digit 9 can only be placed in the cells of the second, third and fourth columns (candidates marked in blue). Thus, we can eliminate the digit 9 from the remaining cells of these columns, which simultaneously see the cell R8C1, so from the cells R7C2, R7C3, R9C2 and R9C3. After applying this method, in the second column the digit 9 can only be placed in the R5C2 cell.