GridWits
Easy tier Technique 4 of 18 Used by Smart Hint

Completed Island

Once an island's marked cells already equal its clue, every cell around it is sea.

How it works

  1. 1The 2 already has both of its cells — the clue and the mark directly below it — so this island is finished.
  2. 2Anything else touching it would join it and push it past its own number.
  3. 3Its three remaining neighbors are therefore all sea.
2 4 1
  • Island (land)
  • Sea
  • Cells that establish the pattern
  • Where the conclusion lands
Next in the ladder Forced Expansion →

An island blocked everywhere but one open cell has no other way to grow — that cell joins it.