Pearl Harbor The path to war between Japan and the United States began in the 1930s, when disputes over China separated the two nations. In 1931, Japan conquered Manchuria, which had until then been part of China. In 1937, Japan launched a long, ultimately unsuccessful campaign to conquer the rest of China. In 1940, the Japanese government allied itself with Nazi Germany in the Axis Alliance, and the following year occupied all of Indochina. The United States, which had important political and economic interests in East Asia, was alarmed by these Japanese measures. . The United States increased its military and financial aid to China, embarked on a program to strengthen its military power in the Pacific, and cut off shipments of oil and other raw materials to Japan. Because Japan was poor in natural resources, its government took these measures into consideration. , particularly the oil embargo as a threat to the survival of the nation. Japanese leaders responded by deciding to seize the resource-rich territories of Southeast Asia, although this move would certainly result in war with the United States. The problem with this plan was the danger posed by the U.S. Pacific Fleet based at Pearl Harbor. Admiral Isoroku Yamamoto, commander of the Japanese fleet, devised a plan to immobilize the American fleet early in the war with a surprise attack. Key elements of Yamamoto's plans were meticulous preparation, achieving surprise, and the use of aircraft carriers. and naval aviation on an unprecedented scale. In the spring of 1941, Japanese carrier pilots began training in the special tactics required by the plan to attack Pearl Harbor. In October 1941, the Naval Staff gave final approval to Yamamoto's plan, which called for the formation of an attack force commanded by the vice president. Admiral Chuichi Nagumo. It was based around six heavy aircraft carriers accompanied by 24 support ships. A separate group of submarines was to sink any American warships that evaded the Japanese naval air force. Nagumo's fleet assembled in the isolated anchorage of Tankan Bay in the Kuril Islands and departed in strict secrecy for Hawaii on November 26, 1941. The ships' route crossed the North Pacific and avoided shipping lanes normal. By dawn on December 7, 1941, the Japanese task force had approached undetected from a point just over 200 miles north of Oahu. At that time, American aircraft carriers were not at Pearl Harbor. On November 28, Admiral Kimmel dispatched the USS Enterprise under Rear Admiral Willliam Halsey to deliver Marine Corps warplanes to Wake Island..