GridWits
Extreme tier Technique 28 of 31 Used by Smart Hint

Jellyfish

Four rows whose homes for a digit occupy just four columns.

How it works

  1. 1The same fish pattern as X-Wing and Swordfish, one size larger again: four lines, four cross-lines.
  2. 2Four rows needing four of the digit, with only four columns able to hold them, use those columns up entirely.
  3. 3Strike the digit from those columns everywhere outside the four rows.
Next in the ladder X-Chain →

One digit, an alternating chain that both starts and ends on a strong link — so one of its two ends holds the digit.