Jellyfish
The four-line extension of the swordfish: a single candidate confined to the same four columns across four rows.
Use when a single candidate is confined to the same four columns (or rows) across four lines.
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Candidate 3 is confined to the same four columns across four rows.
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The 3 is then removed from those four columns in every other row.
- Requiring all four cells in each row — a jellyfish works even if a row uses only some of the four columns.
- Mixing the orientation: eliminate from columns when the base sets are rows, and vice versa.
Frequently asked questions
How is a Jellyfish different from a Swordfish?
A swordfish uses three lines and three columns; a jellyfish extends the same logic to four lines and four columns.