The Finned X-Wing (Row) is the horizontal counterpart to the Finned X-Wing (Col).
In this version, your Base is two Rows, and you are looking to eliminate candidates from the Columns.
The Setup
You are looking for a specific number (let's say 5). You find two rows where the 5 almost forms a perfect rectangle:
- Row A: The 5 can only go in two spots (e.g., Column 1 and Column 7).
- Row B: The 5 can go in Column 1 and Column 7... PLUS an extra spot (the Fin) right next to one of those corners.
The Fin Requirement: This extra spot must be inside the same 3x3 box as one of your X-Wing corners.
Interactive Example
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Click "Apply Logic" to see the strategy in action.
Real Example Explanation
In the interactive example above, look at the number 5:
- Row 2: The 5s are restricted to Column 1 and Column 7.
- Row 8: The 5s are in Column 1, Column 7... and an extra spot at R8C3 (Green).
- The Overlap Logic: Think of it as a backup plan.
- If the Fin is FALSE: The X-Wing is perfect. You can delete 5s from the rest of Column 1.
- If the Fin is TRUE: The 5 is in that little "fin" area (Box 7). You can delete all 5s in the rest of that Box.
- The Kill Zone: We delete the candidate from any cell that is "hit" by both the Column and the Fin's Box.
- The cell R9C1 (Red) is in Column 1.
- The cell R9C1 is also in Box 7.
- Therefore, R9C1 cannot be a 5.
Why "Row" instead of "Column"?
It purely depends on where you spot the restriction first. It's like a flashlight:
- If the Rows are the flashlights, they shine up and down the Columns. (Finned X-Wing Row)
- If the Columns are the flashlights, they shine across the Rows. (Finned X-Wing Col)
Comparison Table
| Strategy | Base (Where you find it) | Target (Where you delete) |
|---|---|---|
| X-Wing (Col) | 2 Columns | Entire Rows |
| Finned X-Wing (Col) | 2 Columns | Intersection of Row & Box |
| X-Wing (Row) | 2 Rows | Entire Columns |
| Finned X-Wing (Row) | 2 Rows | Intersection of Column & Box |
Related Strategies
- Sashimi X-Wing: The incomplete version.
- Swordfish: Expanding the logic to three rows.