Puzzle guide
How to solve Bimaru
Bimaru is the logic version of the old ships game: a fleet is hidden in the sea, and you find every ship without a single shot. The numbers beside the rows and columns say how many cells are ship, and the ships never touch. Here is how to track them down.
The rules
- Hide the fleet shown under the puzzle. Each ship is a straight line of cells, across or down.
- The number beside a row or column says how many of its cells are ship.
- Ships never touch each other, not even at a corner.
- A blue cell is given: it shows part of a ship, and its shape tells you which part.
A solved puzzle
Your first moves
- Fill every row and column with a 0 with water.
- Look at the given cells: an end, a middle or a ship just one cell big tells you a lot about its neighbours.
- Around every ship cell, the four corner cells are water.
- Check the fleet under the puzzle: place the biggest ships first, while there is still room to see where they fit.
Techniques, step by step
Full and empty rows
The top row says 0, so all of it is water. The second row says 3, and only three of its cells are not water yet. All three are ship. Whenever a row or column has as many ship cells as its number, the rest is water; and whenever it has exactly as many free cells as ship cells still missing, all of them are ship.
A ship just one cell big
This given cell shows a round ship just one cell big. It is complete, and ships never touch, not even at a corner. So all eight cells around it are water.
A given end
This given cell is the left end of a ship. The ship goes on to the right, so that cell is ship too. Every other neighbour of the end is water, and so are the cells above and below the next cell, because a ship lying across never has neighbours above or below.
Water at the corners
Ships are straight and never touch at a corner. So the four diagonal neighbours of any ship cell are always water, even before you know which way the ship runs. Put waves on them each time you find a ship cell.
Count the fleet
The fleet under the puzzle tells you which ships are still missing. If the longest ship is already placed, a line of cells that long elsewhere cannot grow any further: close it off with water. And when every ship of the fleet has been found, all cells that are still open are water.
Where can the big ship go?
For the biggest missing ship, look at every place it could still lie: each row and column with enough room and a high enough number. A cell no ship can reach any more is water. If all the places for a ship share a cell, that cell is ship. On medium and hard boards, this is the step that unlocks the rest.
Common mistakes
- Ships touching at a corner. Not even corners may touch. Mark the corners of every ship cell as water.
- Forgetting the fleet. The numbers alone are not enough: the ships must match the fleet shown under the puzzle exactly.
- Bent ships. Every ship is straight, across or down. An L-shape is two ships, and then they would touch.
- Ignoring the shape of given cells. A given end or middle shows which way its ship continues.
Questions and answers
Ready to play?
Empty and full rows, water around every ship, given parts and the fleet count: that is how the whole fleet comes to light.