How to solve a Jellyfish in Sudoku
A Jellyfish is a digit confined to the same four columns across four rows, which clears it from the rest of those columns.
How it works
It is an X-Wing or Swordfish on four rows and four columns. A digit limited to the same four columns in four rows will fill them.
It can be removed from every other cell in those columns. The same applies with rows and columns swapped.
How to spot it
Rare in practice. Look for four rows where a digit has two to four spots that use only four columns between them.
Where it fits in Rocksled Sudoku
Puzzles that need a Jellyfish are never rated below Expert. Each step of this kind adds 110 points to a puzzle’s difficulty score. When you ask for a hint that needs it, the game names the technique and shows the cells involved. See how to play for the rest of the controls.