Sashimi X-Wing

Level 7 · Green Belt

Strategy:

Finned & Sashimi Fish

Requires:

Overview

Sashimi X-Wing is a variant of Finned X-Wing where one of the base cells is missing. The pattern still allows eliminations in cells that see both the fin and the expected elimination zone.

How It Works

Find an almost-X-Wing where one row is missing a candidate in one of the expected columns.
The missing cell creates a 'sashimi' pattern - the fin compensates for the gap.
The fin must be in the same block as the missing cell's expected position.
Eliminate the candidate from cells seeing both the fin and the cover column.

Example

Look for Sashimi X-Wing.

Sudoku grid showing the initial puzzle state for Look for Sashimi X-Wing.

1

Sashimi X-Wing

Check digit 4 in rows 2 and 5. These rows form a X-Wing pattern in columns 4 and 8.

Sudoku grid illustrating step 1: Sashimi X-Wing — Check digit 4 in rows 2 and 5. These rows form a X-Wing pattern in columns 4 and 8.

2

Sashimi X-Wing

r2c1 is already filled with 8.

Sudoku grid illustrating step 2: Sashimi X-Wing — r2c1 is already filled with 8.

3

Sashimi X-Wing

Digit 4 cannot go in r2c2 because r3c2 is already in this column. Remove the entry or choose a different digit.

Sudoku grid illustrating step 3: Sashimi X-Wing — Digit 4 cannot go in r2c2 because r3c2 is already in this column. Remove the entry or choose a different digit.

4

Sashimi X-Wing

r2c3 is already filled with 7.

Sudoku grid illustrating step 4: Sashimi X-Wing — r2c3 is already filled with 7.

5

Sashimi X-Wing

r2c5 is already filled with 5.

Sudoku grid illustrating step 5: Sashimi X-Wing — r2c5 is already filled with 5.

6

Sashimi X-Wing

r2c6 is already filled with 1.

Sudoku grid illustrating step 6: Sashimi X-Wing — r2c6 is already filled with 1.

7

Sashimi X-Wing

r2c7 is already filled with 3.

Sudoku grid illustrating step 7: Sashimi X-Wing — r2c7 is already filled with 3.

8

Sashimi X-Wing

Digit 4 cannot go in r2c9 because r9c9 is already in this column. Remove the entry or choose a different digit.

Sudoku grid illustrating step 8: Sashimi X-Wing — Digit 4 cannot go in r2c9 because r9c9 is already in this column. Remove the entry or choose a different digit.

9

Sashimi X-Wing

r5c1 is already filled with 2.

Sudoku grid illustrating step 9: Sashimi X-Wing — r5c1 is already filled with 2.

10

Sashimi X-Wing

r5c2 is already filled with 3.

Sudoku grid illustrating step 10: Sashimi X-Wing — r5c2 is already filled with 3.

11

Sashimi X-Wing

r5c3 is already filled with 8.

Sudoku grid illustrating step 11: Sashimi X-Wing — r5c3 is already filled with 8.

12

Sashimi X-Wing

r5c7 is already filled with 1.

Sudoku grid illustrating step 12: Sashimi X-Wing — r5c7 is already filled with 1.

13

Sashimi X-Wing

r5c9 is already filled with 5.

Sudoku grid illustrating step 13: Sashimi X-Wing — r5c9 is already filled with 5.

14

Sashimi X-Wing

One base row has extra candidates in box 5. That box is the fin, so this becomes a Sashimi X-Wing.

Sudoku grid illustrating step 14: Sashimi X-Wing — One base row has extra candidates in box 5. That box is the fin, so this becomes a Sashimi X-Wing.

15

Sashimi X-Wing

Because of the fin, only cells in box 5 that also lie in columns 4 and 8 can lose digit 4.

Sudoku grid illustrating step 15: Sashimi X-Wing — Because of the fin, only cells in box 5 that also lie in columns 4 and 8 can lose digit 4.

16

Sashimi X-Wing

These are the cells that see both the fish structure and the fin: r4c4.

Sudoku grid illustrating step 16: Sashimi X-Wing — These are the cells that see both the fish structure and the fin: r4c4.

17

Sashimi X-Wing

Remove 4 from: r4c4.

Sudoku grid illustrating step 17: Sashimi X-Wing — Remove 4 from: r4c4.

18

Result after applying the technique.

Sudoku grid showing the result after applying the technique

Tips & Patterns

Sashimi fish are related to finned fish but with a missing base cell.
The eliminations are identical to the finned version.
If you understand Finned X-Wing, Sashimi follows the same logic.