Battleship solitaire solver: check, solve and explain any board
Type in the row and column numbers, the fleet and any cells the puzzle gives you. The solver tells you whether the board has no answer, one answer or several, shows the answer, and can explain one forced move at a time. It runs in your browser, with no ads and no account, and works for the puzzle family also called Bimaru, Yubotu or solitaire battleships.
Cells the puzzle gives you: tap a cell to cycle empty, water (dot), ship (filled). The numbers you typed are repeated beside the grid. Solver results show in a softer shade than the cells you gave.
What it checks
The standard rules: ships are straight lines of cells, each row and column holds exactly the number of ship cells shown, the whole fleet is used once, and no two ships touch, not even diagonally. Cells you mark as given are respected, and a "ship" mark means that cell holds part of a ship (it does not need to say which part). The count stops at two, because two solutions already means the board is not a fair puzzle.
How the next forced move works
For every empty cell the solver asks whether the board can still be finished if that cell were a ship, and whether it can if the cell were water. A cell where only one of the two works is forced. The reason is given in plain words where a basic rule explains it (a full row or column, or a cell diagonal to a ship). Otherwise the reason is that the fleet and the numbers cannot be satisfied the other way, which is a longer argument the solving guide shows how to make by hand. Large boards with very few given cells can have too many possibilities to count in your browser, and the solver will say so instead of guessing.
Want a fresh board every day to practise on? Shoal is a free daily puzzle in this family: every board has exactly one answer, found by two independent programs, and can be solved with the techniques in the guide.