Battleship Solver,
find the best next shot.

Field guide

How the Battleship Solver works.

In Battleship each player hides a fleet of straight ships on a grid, usually 10 by 10, with ships 5, 4, 3, 3 and 2 cells long. You take turns firing at cells and are told only hit, miss or sunk. Good play is a counting problem: which cell is crossed by the most places a hidden ship could be? This solver does that counting for you after every shot, so you always fire where a ship is most likely to be.

Using the solver

Choose the board size and set the fleet, or keep the standard one. Pick Miss, Hit or Sunk and tap the cells you have fired at; tapping a marked cell again clears it. When you sink a ship, mark its cells as sunk and tap the ship in the fleet list so it is no longer searched for. The board colors every open cell by how likely it is to hold a ship part, the best cell is ringed, and a percentage shows the chance of a hit. After you fire, use the quick buttons under the recommendation, or tap the board, then read the next suggestion.

How the heat map is built

For each ship afloat, the tool lists every horizontal and vertical position that fits on the board without covering a miss or a sunk ship. A cell's chance is the share of a ship's positions that pass through it, added up over the fleet:

The numbers rank the cells, and they are real chances only under the model described below. Edges and corners score low because fewer positions reach them, and the center scores high because many do.

Hunt mode and target mode

With no hit to follow, hunt mode counts every legal position. Once you hit a ship that is still afloat, target mode counts only arrangements in which some ship covers that hit, and a position that covers two hits weighs more than one covering a single hit. Two hits side by side therefore point to the cells at the ends of that line, not the ones above and below.

Worked example

On an empty 10 by 10 board with the standard fleet, a corner cell has a chance of about 7% and the four middle cells about 24%, so you open in the middle. The chances over the whole board add up to 17, the number of cells in the fleet. Now suppose only the 2-cell ship is left and you hit a cell in open water: each of the four neighbors has a 25% chance. If the hit was in a corner, two neighbors remain with 50% each. Press Example to load a mid-game position with two open hits and watch target mode take over.

What the map leaves out

The tool treats each ship as placed on its own, so it can let two ships overlap, which slightly overrates crowded cells. It does not model rules where ships may not touch, and it assumes your opponent places ships at random. If they favor the edges or leave gaps, trust what you have seen over the map.

Tips

• Log every shot. A forgotten miss makes the map think a ship could be sitting on it. Undo steps back one change.
• Finish a ship before hunting again. Auto mode switches to target mode while a hit is open, which is usually the fastest way to turn a hit into a sunk ship.
• Change the fleet to match your rules. Some versions use different ship lengths or counts, and the map recalculates as soon as you edit the fleet.

Disclaimer: This tool is an independent fan creation and is not affiliated with, authorized, or endorsed by Hasbro, Inc. “Battleship” is a trademark of its respective owner and is used here only to describe the type of game. Provided for practice and entertainment only.