Mirrored from Sudopedia, the Free Sudoku Reference Guide
Finned Fish
			Finned Fish is a variety of fish that has extra candidates in a single box. Like regular fish, it is a single-digit solving technique.
The same names are used for the different sizes:
-  Finned X-Wing
-  Size 2
-  Finned Swordfish
-  Size 3
-  Finned Jellyfish
-  Size 4
 How it works 
Here is an example of a Finned X-Wing:
The four cells marked X would be an X-Wing if the candidate in the cell marked F were not present. So either there is an X-Wing, or the candidate in F is true. In both cases, the starred cells cannot contain a candidate for this digit. We can eliminate those candidates.
The eliminated candidates can only be within the box containing the fin.
The F cell is known as the fin. In this example, there could also be a candidate in r5c3. This would be called a big fin, but the effects are the same.
 See also 
This page was last modified 03:32, 31 December 2009.