Battleship

Goal: Battleship is a hidden-information duel on a 10×10 grid. Deploy your units secretly, then take turns firing at coordinates. In Classic mode the first side to sink all 5 enemy ships wins; in Plane Mode the first side to destroy all 3 enemy plane noses wins.

Setup

Each player secretly places a fleet on their own grid:

• Classic: Carrier (5 squares), Battleship (4), Cruiser (3), Submarine (3) and Destroyer (2) — 17 squares in total.
• Plane Mode: 3 planes of 12 squares each. Every plane has exactly one nose, its only vital square.

Ships lie horizontally or vertically; planes face up, right, down or left. Units may never overlap or stick out of the grid, although in Classic mode ships are allowed to touch. Use Rotate to change facing, tap a square to place the selected unit, tap a deployed unit to pick it up again, or press Random for an instant legal deployment.

Turns and feedback

Players alternate firing one shot per turn at any square of the enemy grid:

• Miss — empty water.
• Hit (Classic) — part of a ship is damaged; hit every one of its squares to sink it, and the sinking is announced.
• Hit (Plane Mode) — you struck the airframe but not the nose.
• Nose hit (Plane Mode) — the plane crashes immediately, whatever part of it is still undamaged. Only the nose square is revealed; the rest keeps reporting hits if you fire at it later.

A square cannot be shot twice. All previous shots stay marked on the grid, so use them to build a picture of the enemy deployment.

Winning

• Classic: sink Carrier, Battleship, Cruiser, Submarine and Destroyer — all 17 squares.
• Plane Mode: destroy all 3 enemy noses. Wings, bodies and tails never need to be hit.

Pass & Play

Choose Pass & Play to share one device with a friend. After each deployment and every shot, a full-screen privacy curtain hides the boards until the next player confirms they are ready, so nobody can peek at the opponent's fleet.

Fair play

The AI never peeks at your fleet. It plans every shot from the same miss, hit and sinking feedback you receive — random fire on Easy, probability heatmaps on Normal, and heatmaps plus hunt/target search on Hard.

Hunting: do not fire at random. In Classic mode every ship is at least 2 squares long, so a checkerboard sweep — every other square — guarantees you will touch something eventually. The Hard AI hunts exactly this way.

• After a hit, fire at its four neighbours before wandering off: ships lie in straight lines, so the follow-up shot carries the information.
• When a ship sinks, work out which of your hits it must have used; any leftover hits belong to other ships and are gold.
• Center squares belong to more possible ship placements than corners, so probability concentrates toward the middle of the board.

Plane Mode: a plane is a fat cross, so wounded squares appear quickly. Each wound anchors the shape — the wings span a full row of five and the tail sits behind the body. When you find a hit, test the four directions in your head and ask which nose positions could produce that shape without contradicting your misses; usually only one or two candidates survive.

• The nose is the only vital square: once the orientation is clear, aim straight for where the head must be.
• Destroyed planes still report hits on their remaining squares — do not let old wreckage pull your attention from live planes.

Deployment: avoid tidy lines. Clustering ships away from the center hides them behind early misses, while overlapping plane outlines creates ambiguity for the attacker. Most of all, break symmetry — predictable, symmetrical fleets are found first.

Battleship is the classic hidden-fleet duel, commercially popularized by Milton Bradley in 1967 with plastic grids and pegs. Its roots reach back to pencil-and-paper games of the early 20th century, and it was among the first board games adapted to computers — even one of the earliest games playable over telephone lines.

This page also includes Plane Mode, a Chinese paper-and-pencil cousin often called Bomb Plane. Instead of straight ships, each side draws three 12-square planes, and only the nose square sinks a plane. It was a classroom favourite in China for decades, played on grid paper with two pencils.

Implementation notes:

• 10×10 grid with the classic 5-ship fleet (17 squares) in Classic mode.
• Three fair-play AI levels, from random fire to probability heatmaps with hunt/target search.
• Pass & Play with a privacy curtain for two players on one device.

This is an unofficial, fan-made implementation for education and entertainment. Battleship is a trademark of its respective owner.