Naval War is a light system of naval combat, not intended to represent any actual tactics of historical naval battles, in which players may operate ships from opposing navies side-by-side. All ships depicted in the game were involved in World War II. The basic mechanic is one where ships have different size guns and players have cards which are different size ammunition. A player must match ammo to the guns to fire and damage other players' ships. Players have multiple ships and the winner is the last player with ships afloat; in the latest edition, winning is based on points from sinking enemy ships.