Battleship Game: Its History, Standard Rules and How to Play It Online

Battleship is a two-player guessing game in which each side hides a fleet of ships on a grid and calls out coordinates, trying to sink the opponent's vessels before its own are found. This page covers the standard fleet and rules, the Salvo variant, where the game came from, and the probability math that separates a lucky guesser from a systematic hunter. A playable Battleship grid on this page pits a visitor against a computer opponent that hunts on a fixed search pattern, described in detail below.

Origins: From Pencil and Paper to a Plastic Pegboard

The game's ancestry goes back further than its 20th-century commercial releases. Diary entries from the Russian poet Ryurik Ivnev describe officers playing a pencil-and-paper guessing game resembling Battleship as early as 1907, years before any commercial edition appeared, and researchers have also drawn parallels to Basilinda, an 1890 game published by E. I. Horsman.

The first version sold under a brand name was Salvo, released by the Starex company in 1931. Through the 1930s and into the war years, several publishers sold their own paper-pad versions of the same idea: Milton Bradley's "Broadsides: A Game of Naval Strategy," published in 1943, and Maurice L. Freedman's "Warfare: Naval Combat" among them. Each came as a pre-printed pad of grids that players filled in with a pencil, one grid per game.

Milton Bradley turned the concept into a physical product in 1967, when it released a plastic pegboard version under the Battleship name, with red and white pegs replacing the paper grid. The format stuck. Ten years later, in 1977, the same company followed up with Electronic Battleship, an early microprocessor-based toy that added sound effects to hits and misses. Computer versions arrived soon after: a Battleship game ran on the Z80 Compucolor as early as 1979, and by the late 1980s and 1990s the game had reached most home computers and consoles of the era, including a 1987 release across the ZX Spectrum, Commodore 64, Amstrad CPC, BBC Micro and Amiga, a 1993 version for the NES and Game Gear, Super Battleship the same year for the Genesis and Super NES, and a PC version in 1996.

Standard Rules and Fleet

Each player commands a fleet placed on a private 10x10 grid, hidden from the opponent, while a second grid is used to track shots fired at the enemy fleet. Under the rules Milton Bradley standardized in 1990, the fleet consists of five ships of different lengths:

Ships are placed horizontally or vertically, never diagonally, and cannot overlap. Whether they may touch edge to edge is left to house rules, since the official instructions do not forbid it. Players alternate calling a single grid coordinate per turn; the opponent reports a hit or a miss, and once every square of a ship has been hit, its owner must announce which ship was sunk. The first player to sink all five enemy ships wins.

In 2002, Hasbro revised the fleet for a new edition, renaming the three-square Cruiser to Destroyer and adding a two-square Patrol Boat, so the exact ship names on a given set depend on which edition it belongs to.

The Salvo Variant

Salvo, the name of the original 1931 edition, is also the term for a variant rule still offered in later Milton Bradley and Hasbro rulebooks. Instead of firing one shot per turn, each player calls out several coordinates at once, and the opponent reports the results only after all of them have been announced. The number of simultaneous shots typically starts at five and drops by one each time a ship is sunk, though some rule sets fix the shot count at five for the whole game or tie it to the number of ships a player still has afloat. Salvo speeds up play and removes some of the guesswork rhythm of the one-shot version, at the cost of giving less immediate feedback after each individual call.

Playing the Odds: Search Strategy and Probability

Because the grid is large and the fleet is hidden, competitive players and computer opponents alike rely on search strategies grounded in probability rather than random guessing.

The simplest of these is parity, or checkerboard, hunting. Colour the 100 squares of a 10x10 grid like a chessboard, alternating light and dark; since the shortest ship in the standard fleet is the two-square Destroyer, no ship can be placed anywhere on the board without covering at least one square of each colour. That means limiting a search to just one colour, 50 of the 100 squares, still guarantees landing a first hit on every ship on the board, cutting the average number of shots needed to find a fleet roughly in half compared with checking every square in sequence.

Once a shot lands a hit, the strategy switches from hunting to targeting: the searcher checks the four squares directly adjacent to the hit, up, down, left and right, rather than continuing the checkerboard pattern, since a ship occupies a straight line of contiguous squares. A second hit next to the first reveals the ship's orientation, horizontal or vertical, and the remaining shots follow that line in both directions until the ship is sunk or a miss marks its far end.

More advanced computer players go a step further with a probability-density approach: for every empty square, the program counts how many of the ship placements still consistent with the board's known hits and misses would occupy that square, then fires at the square with the highest count. Early in the game, before any hits have landed, this method produces a heat map that favours the centre of the board and the middle of open rows and columns, simply because more ways exist to fit a five-square Carrier or four-square Battleship through the middle of the grid than along its edges.

How the Computer Opponent on This Page Plays

The playable Battleship grid on this page follows the two search modes described above rather than firing at random. In its hunting phase it fires only on squares that follow a checkerboard pattern, guaranteeing a hit on any ship without wasting shots on squares no ship could occupy alone. Once it scores two hits on the same ship, it stops treating the board as a checkerboard and follows the line those two hits establish, firing along that row or column until the ship is sunk before returning to its checkerboard search for the next target.

Computer Versions of Battleship on This Site

The idea of a hidden grid and a hunt for enemy ships has been extended many times on computer platforms, several of which are described in more detail elsewhere on this site.

BattleFleet 1939 and BattleFleet: Pacific War turn the static Battleship board into a turn-based naval strategy game: ships, submarines and aircraft can move across a map instead of sitting fixed in one square, and a mission can call for conquering ports or escorting a convoy rather than simply sinking every enemy hull. Battleship game variants compared and how Pacific War extends the Battleship rules both cover this extension in more detail, and Battleship Game WW2 applies the same movement-and-radar approach to a full World War 2 setting with fifty unit types.

Other computer implementations stayed closer to the original grid-guessing format. Battleship PC Game is a straightforward digital port of the classic board game; Battleship Chess Game describes a variant that replaces grid guessing with chess-like unit movement across five chapters; Armada Battleship Game and Battleships General Quarters II are both implementations of the traditional ship-hiding format for a single computer, one built in Java and the other pitting a human player against a five-ship computer fleet; and SeaWar: The Battleship Game together with SeaWar 2: The Battleship Game cover a pair of 3D battleship titles built around underwater and surface combat effects.