The game is played on four square grids, two for each player. The grids are typically square – usually 10 × 10 – and the individual squares in the grid are identified by letter and number. On one grid the player arranges ships and records the shots by the opponent. On the other grid, the player records own shots.
Before play begins, each player arranges a number of ships secretly on the grid for that player. Each ship occupies a number of consecutive squares on the grid, arranged either horizontally or vertically. The number of squares for each ship is determined by the type of the ship. The ships cannot overlap (i.e., at most one ship can occupy any given square in the grid). The types and numbers of ships allowed are the same for each player. These may vary depending on the rules.
There are two typical complement of ships, as given in the Milton Bradley version of the rules:
The number of target squares that a player may shoot at in a given turn is determined by the condition of the players' own ships at the beginning of the round. Each player has many shots as he or she has vessels afloat in each turn. Thus each time a player's ship is entirely destroyed, that player has one fewer shot on all subsequent turns.
Various Battleship variants for home video game consoles have been produced, including Battleship for the Nintendo Entertainment System (with a port to the Sega Game Gear), Battleship for the Nintendo Game Boy (different from the NES version),Super Battleship for the Super Nintendo and Sega Genesis, Batleship for the Game Boy Color, Battleship for the CDI, Battleship for the Amiga, Atari ST, Commodore 64, ZX Spectrum, Risk / Battleship / Clue, for the Game Boy Advance , Battleship / Connect Four / Sorry! / Trouble for the Nintendo DS, Monopoly / Boggle / Yahtzee / Battleship for the Nintendo DS, Battleship has also been released on mobile phones, there also have been multiple versions of Battleship released on the PC, Battleship: Surface Thunder for the PC, TotalBattleship for the PC, Battleship was also part of Hasbro Family Game Night for the Playstation 2 and Wii. These alter the rules, including the size of the grid (8 x 12 in the NES version, 8 x 8 in the Game Boy version), size of ships (it is common to feature a submarine that takes up only a single square) and special shot missiles for each ship (for example, in the NES version the cruiser has a 5-shot missile which strikes 5 squares in an X pattern on the grid in one turn. Submarine-tracking sonar and aerial reconnaissance to spot ships are also features). RNASoft created Naval Attack based upon Battleship for Toshiba SPANworks which was also used as a technology demo for Toshiba SPANworks' ImmediaNet SDK for WiFi based devices like laptop, PDAs, Windows Mobile and users could play across the platform.