Bimaru Solving Tips
Bimaru is solved by placing water as much as ships. New? Read the rules first.
1. Water first
Every ship part has water on its four diagonals; an end piece has water on three sides. Mark it all before anything else.
2. Zeros and full lines
A 0 means a line of water. A count equal to the unknown cells left in a line means they are all ship.
3. The big ship
The 4-cell ship needs a line with at least four cells of room and a count of at least 4 along it (or across four lines). Usually only one or two places fit; try each against the counts.
4. Count the fleet
Add up ship cells placed so far by ship length: if both 3-cell ships are placed, any run of three you find must be split by water.
5. Ends point
A revealed end continues in the direction it points for at least one more cell, and the cell behind it is water.
6. Submarines last
Single-cell ships fill in last: they are the lonely ship cells left once every longer ship is accounted for, each in its own pocket of water.
Frequently asked questions
How do I start a Bimaru puzzle?
Fill water in every row and column with a 0, mark the diagonal neighbours of revealed ship parts as water, and extend revealed ends in the direction they point. Then look for where the longest ship can still fit.
Last updated 2026-10-21