The Board
The game is played using a pair of grid holders that resemble small plastic briefcases. Each side of the holder contains a grid consisting of 10 vertical rows, numbered one through 10, and 10 horizontal rows, lettered A through J. When the grid holder is opened, one grid lies flat on the tabletop and the other stands perpendicular to the tabletop facing the player. The player uses the flat grid to position his ship pieces. The perpendicular grid is used to mark the spots he guesses for the locations of his opponent's ships. It also hides the position of the player's pieces.
The Pieces
Each player has five ship pieces, which she may place horizontally or vertically on her grid wherever she wishes. The aircraft carrier takes up five slots on the grid, the battleship takes up four slots, the cruiser and the submarine both take up three slots and the destroyer takes up two slots. Each player has red and white pegs that fit into the slots on the grids. The white pegs are used to mark misses, while the red pegs denote hits.
Playing
Players decide who goes first by flipping a coin or applying some similar method. On his turn, each player selects a spot on the grid, such as "H-6" or "A-9," and calls it out. If his opponent has a ship in that location, he replies "hit," and tells which ship was struck; otherwise, he replies "miss." The player then places a red or white peg on his perpendicular grid to note the spot. If all the slots occupied by a given ship have been targeted in this manner, that ship is sunk, and the opponent must declare which ship it is. Play proceeds back and forth in this manner until one player sinks all five of the other player's ships.
Salvo Rules
Salvo rules are intended for more experienced "Battleship" players. On each turn, instead of calling out one grid spot, the player calls out five spots, marking hits and misses accordingly. If she ever loses one of her ships, she can henceforth only call out four spots on her turn. If she loses a second ship, she can only call out three spots, and so on until she wins or her entire fleet is sunk.