U.S. moves. Under the Tripartite Pact, Japan is theoretically obliged to fight if the U.S.A. attacks Germany (paragraph 8). The War in China must be continued not only for the sake of prestige but also to safeguard those economic gains already secured. This imposes additional restraint. (paragraph 9). 4. Japan's greatest need is for oil. If outside sources of supply were cut off, her stocks are probably sufficient for nine months active warfare. (paragraph 13). 5. The Japanese Navy consists of ten capital ships, eight aircraft carriers, and a number of cruisers and light craft.