Units represented in the game are individual ships of heavy cruiser size or larger, with provisions also given for convoys, submarines, and air power. Each turn represents a period of roughly six months. The board represents the Atlantic Ocean and the Mediterranean Sea, which are divided up into six zones. Control of as many of these zones as possible, for as many turns as possible, is the goal of the game. One player assumes the role of the Allied player, and controls the British, Soviet, and American navies. His or her opponent is the Axis player, and controls the German and Italian navies. In addition to the units representing individual ships, both players have one unit each that represents land-based airplane squadrons, and the Axis player has units that represent squadrons of U-Boats. Ships are represented by a single counter which typically gives three factors: gunnery, armor, and speed. While these are the essential statistics for surface vessels, this system keeps them all highly abstracted, as each is just a simple number, falling within a range of 0 to 9. Aircraft carriers have a fourth factor, in this case representing the naval air-power on board. The land-based air units each represent three air attacks. Each turn begins with both players' ships in ports. The Allied player's ports include England, the United States, Leningrad, "Russia", and Malta, in the Mediterranean. The Axis player's ports include Germany, France, and Italy. Each turn, each player moves all, some, or none of his ships into sea areas that are adjacent to the port in which those ships started the turn. Ships can also attempt to move one additional sea area if the first area was not controlled by the enemy on the previous turn; to accomplish that, the ship must roll a die and get a result less than that ship's speed factor. Ships that have a speed factor of seven or eight are thus automatically able to move two spaces, and are therefore very valuable. The proviso that the first area may not have been controlled by the enemy allows either player to make certain that areas of the sea are unreachable to the enemy fleet due to intervening controlled areas. Ships that remain in port instead of moving are able to repair damage that they may have sustained in previous turns. When the Allied player is finished, the Axis player moves his ships. U-boats are able to move to any sea area and are therefore the only ships that cannot be blockaded by enemy control. If only one player's ships occupy a sea area after movement is finished, that player controls the sea area for the turn, and he or she scores points for it. If there are ships from both sides in the same sea area, the two fleets must fight at least one round of combat. Combat is resolved with each ship picking a target and rolling one die per gunnery factor, and each 'hit' is re-rolled to produce the amount of damage generated, which is applied to the target's armor factor. If the amount of damage exceeds the armor factor, the ship is sunk. Air attacks are resolved by rolling one die for each attack at a number of targets equal to the air factor. On a roll of five, the ship is disabled, which means that it is forced to return to port. This method generates a lot of dice rolls, and gave the game the nicknames 'Dice at Sea' and 'Yahtzee at Sea', with critics arguing that it depended too much upon luck, and supporters countering that the high number of die rolls actually allows the luck to even out. Minor rules include provisions for U-boat combat, the 'neutral port' of South America, convoys, and the possible internment of the Italian fleet if the Allies control the Mediterranean Sea for much of the game.
Variations
Numerous variations were published for War at Sea in the years since it was released. Many of them appeared in the General, Avalon Hill's house magazine. Among these variations are rules for the French Navy, the Greek Navy, a third Russian port on the Black Sea, Allied mini-submarines, and additional ships that were not represented in the original game. These variations add simulation detail to the game, but at the expense of making it slightly harder to play.
