GridWits
Hard tier Technique 7 of 12 Used by Smart Hint

Placement Overlap

Every spot the remaining ship could still occupy passes through these cells — they're ship no matter which spot is right. A finished ship already fenced in by water never counts as a spot for its same-sized twin, which is often what leaves just one place left.

How it works

  1. 1One 3-ship is all that's left, and every row below the top one is already water, so it has to lie in the top row.
  2. 2A row of four gives it exactly two spots: the left three cells, or the right three.
  3. 3Both spots pass through the middle two cells — mark those as ship no matter which spot is right.
3 0 0 0
  • Ship segment
  • Water
  • Cells that establish the pattern
  • Where the conclusion lands
Next in the ladder Keep Room for the Ship →

A ship here would block every remaining spot for one of the ships still to place, leaving it nowhere to go — so this cell is water.