Franken X-Wing

Level 9 · Purple Belt

Strategy:

Franken Fish

Overview

Franken X-Wing extends the basic X-Wing by allowing boxes as base or cover sets alongside rows and columns. This mixed use of houses creates fish patterns impossible with standard rows/columns alone.

How It Works

  1. Find a digit confined to 2 houses in the base set (mix of rows, columns, and boxes).
  2. The cover set uses 2 houses from the remaining types.
  3. Base and cover must use at least one box to be 'Franken' (otherwise it's a basic fish).
  4. Eliminate the digit from cover set cells not in the base set.

Example

Starting position

Look for Franken X-Wing.

1

Found a Franken X-Wing on digit 2

Found a Franken X-Wing on digit 2. The base set is: Row 8, Box 1.

2

2 is confined to the cover set

The cover set is: Column 2, Column 3. Digit 2 in the base set is confined to these 2 cover houses.

3

Cover-only 2 candidates can be removed

Any 2 in a cover house but outside the base set can be eliminated.

4

Cover candidates outside the base set

These cover-set candidates are outside the base set and must be removed: .

5

Remove 2 from

Eliminate 2 from .

6

Result

Result after applying the technique.

Tips & Patterns

  • Franken fish mix boxes with lines in the base/cover sets.
  • A basic fish uses only rows vs columns; Franken adds boxes to the mix.
  • These are harder to spot but follow the same covering logic.