Jellyfish Sudoku Technique — 4×4 Fish Pattern Guide

A Jellyfish can be found when four or match up in parallel . We can then safely remove candidates in the opposite lines.

How it works

Find the first Row

This Row has a — digit 7 appears in two or three cells.

Find another matching Row

This Row also has 7 in two or three cells — and in the same Columns.

Find a third matching Row

This Row lines up too — still in the same Columns.

Find the fourth matching Row

This Row lines up too — all four Rows share exactly four Columns.

Only possible outcomes

We know 7 must land once in each Row.

Spot the relationship

No matter which order we place 7 in the Rows, each of the Columns will have one 7 too.

Eliminate other cells

We can safely remove other 7 from the Columns.

9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Find the first Row
This Row has a — digit 7 appears in two or three cells.
9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Find another matching Row
This Row also has 7 in two or three cells — and in the same Columns.
9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Find a third matching Row
This Row lines up too — still in the same Columns.
9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Find the fourth matching Row
This Row lines up too — all four Rows share exactly four Columns.
9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Only possible outcomes
We know 7 must land once in each Row.
9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Spot the relationship
No matter which order we place 7 in the Rows, each of the Columns will have one 7 too.
9
8
7
1
5
1
2
3
4
2
4
6
2
2
4
5
1
2
4
6
2
4
6
7
1
2
4
6
1
2
4
6
9
3
2
5
8
2
3
4
5
2
3
4
6
2
3
4
6
6
9
8
2
3
4
6
9
1
2
4
5
7
2
5
7
6
2
3
4
5
1
8
9
1
4
7
9
1
4
8
9
2
3
4
7
8
1
2
4
7
9
1
2
3
7
8
2
4
8
2
4
2
4
8
9
1
5
6
8
9
3
1
4
6
8
9
2
4
7
8
1
2
4
5
7
9
1
2
5
6
7
8
1
7
3
4
8
9
2
4
6
9
4
6
8
9
3
4
8
4
5
9
3
5
6
8
2
3
7
8
2
3
6
1
6
8
9
2
6
9
5
2
3
7
2
7
4
2
3
9
2
3
6
4
1
2
6
7
5
8
1
2
3
2
4
7
8
5
2
4
8
3
1
2
1
2
8
6
1
2
7
9
Eliminate other cells
We can safely remove other 7 from the Columns.

All Hints

Unlock hints to find
the Jellyfish on your board.

Next up

Finned X WingHard