Bases can be converted by isolation or by invasions conducted by amphibious units of either side. The navies of the Japanese Empire, USA, Britain, the Netherlands, and Australia are represented, but the US Navy is by far the major Allied force. The ship counters include all fleet and light aircraft carriers, battleships, and heavy cruisers used by both sides. There is a single submarine counter for each side, but only one is in play at a time. The main function of subs in VITP is carrier hunting.
Ships have three numerical factors which represent gunnery, armor, and speed.
Aircraft carriers also have an airstrike factor. In combat a ship rolls a number of 6 sided dice equal to its gunnery or airstrike factor. The game is eight turns long, but has provisions for an optional 9th turn. There are also a number of other optional rules in the rulebook, however none of the options are used at the convention events I have attended over the years. The sequence of play is broken into several segments in which the Japanese is required to move first in each segment.