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.
How it works
- 1Say the 4-ship and one 3-ship are still to place. On a board this size the 4-ship needs a whole row or a whole column.
- 2The three water cells cut four of those eight lines too short — the top row, the third row, the first column and the third column — so the 4-ship has exactly four homes left.
- 3Each highlighted cell belongs to one of those four homes, and each sits directly against the marked cell.
- 4A ship there would therefore touch the 4-ship wherever it went, leaving the biggest ship in the fleet nowhere to go — so the marked cell is water.
- Water
- Cells that establish the pattern
- Where the conclusion lands