Sashimi Jellyfish

Level 9 · Purple Belt

Strategy:

Finned & Sashimi Fish

Requires:

Finned Jellyfish

Overview

Sashimi Jellyfish is the four-row variant of sashimi fish. A Jellyfish pattern with missing base cells, compensated by fins, allows restricted eliminations.

How It Works

Find an almost-Jellyfish with missing base candidates.
Fin cells in the same block compensate for the gaps.
Eliminate the candidate from cells seeing both the fin block and the cover columns.

Example

Look for Sashimi Jellyfish.

Sudoku grid showing the initial puzzle state for Look for Sashimi Jellyfish.

1

Sashimi Jellyfish

Check digit 4 in columns 2, 3, 5 and 9. These columns form a Jellyfish pattern in rows 1, 6, 8 and 9.

Sudoku grid illustrating step 1: Sashimi Jellyfish — Check digit 4 in columns 2, 3, 5 and 9. These columns form a Jellyfish pattern in rows 1, 6, 8 and 9.

2

Sashimi Jellyfish

r2c2 is already filled with 1.

Sudoku grid illustrating step 2: Sashimi Jellyfish — r2c2 is already filled with 1.

3

Sashimi Jellyfish

r3c2 is already filled with 8.

Sudoku grid illustrating step 3: Sashimi Jellyfish — r3c2 is already filled with 8.

4

Sashimi Jellyfish

r4c2 is already filled with 3.

Sudoku grid illustrating step 4: Sashimi Jellyfish — r4c2 is already filled with 3.

5

Sashimi Jellyfish

r5c2 is already filled with 5.

Sudoku grid illustrating step 5: Sashimi Jellyfish — r5c2 is already filled with 5.

6

Sashimi Jellyfish

r7c2 is already filled with 2.

Sudoku grid illustrating step 6: Sashimi Jellyfish — r7c2 is already filled with 2.

7

Sashimi Jellyfish

r2c3 is already filled with 9.

Sudoku grid illustrating step 7: Sashimi Jellyfish — r2c3 is already filled with 9.

8

Sashimi Jellyfish

r3c3 is already filled with 2.

Sudoku grid illustrating step 8: Sashimi Jellyfish — r3c3 is already filled with 2.

9

Sashimi Jellyfish

Digit 4 cannot go in r4c3 because r4c4 is already in this row. Remove the entry or choose a different digit.

Sudoku grid illustrating step 9: Sashimi Jellyfish — Digit 4 cannot go in r4c3 because r4c4 is already in this row. Remove the entry or choose a different digit.

10

Sashimi Jellyfish

r5c3 is already filled with 7.

Sudoku grid illustrating step 10: Sashimi Jellyfish — r5c3 is already filled with 7.

11

Sashimi Jellyfish

Digit 4 is not a current candidate in r7c3 because earlier solving steps already removed it.

Sudoku grid illustrating step 11: Sashimi Jellyfish — Digit 4 is not a current candidate in r7c3 because earlier solving steps already removed it.

12

Sashimi Jellyfish

r2c5 is already filled with 3.

Sudoku grid illustrating step 12: Sashimi Jellyfish — r2c5 is already filled with 3.

13

Sashimi Jellyfish

r3c5 is already filled with 7.

Sudoku grid illustrating step 13: Sashimi Jellyfish — r3c5 is already filled with 7.

14

Sashimi Jellyfish

Digit 4 cannot go in r4c5 because r4c4 is already in this row. Remove the entry or choose a different digit.

Sudoku grid illustrating step 14: Sashimi Jellyfish — Digit 4 cannot go in r4c5 because r4c4 is already in this row. Remove the entry or choose a different digit.

15

Sashimi Jellyfish

r5c5 is already filled with 1.

Sudoku grid illustrating step 15: Sashimi Jellyfish — r5c5 is already filled with 1.

16

Sashimi Jellyfish

r7c5 is already filled with 9.

Sudoku grid illustrating step 16: Sashimi Jellyfish — r7c5 is already filled with 9.

17

Sashimi Jellyfish

r2c9 is already filled with 7.

Sudoku grid illustrating step 17: Sashimi Jellyfish — r2c9 is already filled with 7.

18

Sashimi Jellyfish

r4c9 is already filled with 8.

Sudoku grid illustrating step 18: Sashimi Jellyfish — r4c9 is already filled with 8.

19

Sashimi Jellyfish

r5c9 is already filled with 2.

Sudoku grid illustrating step 19: Sashimi Jellyfish — r5c9 is already filled with 2.

20

Sashimi Jellyfish

r7c9 is already filled with 3.

Sudoku grid illustrating step 20: Sashimi Jellyfish — r7c9 is already filled with 3.

21

Sashimi Jellyfish

One base column has extra candidates in box 3. That box is the fin, so this becomes a Sashimi Jellyfish.

Sudoku grid illustrating step 21: Sashimi Jellyfish — One base column has extra candidates in box 3. That box is the fin, so this becomes a Sashimi Jellyfish.

22

Sashimi Jellyfish

Because of the fin, only cells in box 3 that also lie in rows 1, 6, 8 and 9 can lose digit 4.

Sudoku grid illustrating step 22: Sashimi Jellyfish — Because of the fin, only cells in box 3 that also lie in rows 1, 6, 8 and 9 can lose digit 4.

23

Sashimi Jellyfish

These are the cells that see both the fish structure and the fin: r1c8.

Sudoku grid illustrating step 23: Sashimi Jellyfish — These are the cells that see both the fish structure and the fin: r1c8.

24

Sashimi Jellyfish

Remove 4 from: r1c8.

Sudoku grid illustrating step 24: Sashimi Jellyfish — Remove 4 from: r1c8.

25

Result after applying the technique.

Sudoku grid showing the result after applying the technique

Tips & Patterns

Sashimi Jellyfish are extremely rare.
Master simpler fish patterns before attempting to find these.
Computer solvers handle these most reliably.