Okinawa is Japan's southernmost prefecture lying between mainland Japan and Taiwan off China's east coast. The main island measures twice the size of Guam and has a population roughly seven times greater, or one-third the size of New York's Long Island with 50,000 more people. On its slender, irregularly shaped island, which constitutes a mere 0.3 per cent of the country, Okinawa hosts 75 per cent in size of all U.S. only military bases in Japan, exclusive of sea and air space. U.S. bases include the Marine Corps jungle training, aviation, bombing and shooting ranges, landing training grounds and an ammunition depot, the largest Air Force base in the region with its own ammunition site, a naval station often visited by nuclear submarines and Army facilities, adding in sum to roughly one-fifth of the densely populated island. It is home to an estimated 24,600 U.S. service personnel, out of a total of 36,000 in all of Japan, many of them living with their dependents in fenced-in “American towns” with schools, gyms, golf courses, shopping centers and churches. Nearly 90 per cent (about 15,000 in number) of the Japan-based Marines are concentrated in Okinawa.