GridWits

Land Squeeze

Expert Used by Smart Hint

The mirror image of Contested Space: if making a cell land would break the board right away — overflowing the island it would join, or walling a different island off from the room it still needs — then it's sea.

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How it works

  1. Contested Space asks what breaks if a cell becomes SEA. This asks the opposite question: what breaks if it becomes LAND?
  2. A land cell touching exactly one island has to join that island — there's nowhere else for it to belong. So try it: add the cell, and see whether the island now overshoots the number on its clue.
  3. Also check the rest of the board, not just that one island: claiming the cell may be what walls a DIFFERENT island off from the last open squares it needed to reach its own number.
  4. If either happens, the cell could never have been land. It's sea.