Battleship

Rules

Two players, a grid of 10 × 10 cells each, and a fleet of 10 ships hidden in it. Every rule below is enforced at the table, in the order a game runs.

In short

Each side hides 10 ships: 1 of four cells, 2 of three, 3 of two and 4 of one.
Ships are straight, across or down, and never touch — not along a side, not at a corner.
A shot is one cell, answered at once: miss, hit, or sunk.
A hit or a sinking shoots again; a miss passes the turn.
Sink the whole fleet first to win.

The grid

Each side has a grid of 10 × 10 cells, its columns lettered and its rows numbered from 1 to 10. A cell is written as its letter and its number: E5.

The fleet

Each side has the same fleet of 10 ships, 20 cells in all: 1 ship of four cells, 2 of three, 3 of two and 4 of one. A ship is a straight line of cells, across or down; it is never bent and never diagonal.

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A fleet as it may be placed: one ship of four, two of three, three of two and four of one, none touching another.

Placing

Both sides place their whole fleet in secret before the first shot. No two ships may touch, not along a side and not at a corner: every cell round a ship is water. A fleet that breaks the rule is refused, and placed again.

Who fires first

In a match's first game, a lot decides. In every later game, whoever lost the last game fires first.

A shot

A shot is one cell of the opponent's grid, and it is answered at once and truthfully: miss, hit, or sunk when it hits the last cell of a ship. A sunk ship is shown, all of it.

Hit, and fire again

A miss passes the turn. A hit or a sinking earns another shot, and a turn may hold as many as you can make.

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One shot, one hit. The four corners of the hit are crossed out — no ship can be there — and the shooter fires again.

What is crossed out

Ships never touch, so some cells can only be water. After a hit, its four corners are crossed out; after a sinking, every cell round the ship. A shot at a crossed-out cell, or at a cell already fired at, is refused, and you still have your shot.

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A ship of three sunk across the top, the whole border round it crossed out, and a miss that passed the turn.

The end of a game

Whoever sinks the opponent's last ship wins. There is no last shot for the side that fired second, and no draw. At the end, both fleets are shown.

A match

A match is one game, or the best of three or five: the first to win a majority of the games wins it.