Finned X-Wing Technique is in some way related to the X-Wing.

If the cell marked 'F' does not exist, then the four cells marked with 'X' form an X-Wing. So we can draw a conclusion: either the candidates of the cell marked with 'F' has the digit, or the cells marked with 'X' can apply X-Wing Technique. In whatever cases, the candidates in cells marked with '*' cannot have the digit thus it can be eliminated from those cells.

Here is an example:

Suppose if [B6]≠2, then [B4],[B9],[I4] and [I9] form an X-Wing, so [A4] cannot have digit 2. Or, if [B6] = 2, [A4] again cannot have digit 2.Therefore, we can safely remove digit 2 from the candidates in cell [A4].

Here is another example:

Suppose if [C8]≠4, then [B3],[E3],[B8] and [E8] form an X-Wing, so [B9] cannot have digit 4. Or, if [C8]=4, [B9] again cannot have digit 4, since it lies within the cells that intersect both Row B and the Block starting at [A7]. Therefore, we can safely remove digit 4 from the candidates in cell [B9].

You can find more examples below:

See also: ««  Direct Elimination Techniques  »» ««  Candidates Elimination Techniques  »»