**Swordfish**
This technique is similar to the

X-Wing technique, except it looks at

__three__ rows and columns. If three rows have a candidate in up to three cells that lie on the same three columns, then the candidate can be eliminated from all other cells in the those columns.

Consider the partial Sudoku below with the candidate 4 in the following cells.

In

rows 2, 4, and 7, the candidate 4 exists up to three times in each row and lies in

exactly three columns. This arrangement of cells must contain a 4 in each column of

the Swordfish. So, we can eliminate the candidate 4 from

all other cells in columns 1, 3, and 6.

Note: You can swap columns and rows when performing this technique.

Copyright©2021 Decabit Software

Last Updated: 10/19/2021 8:56:23 AM CST