When the nations of Western Europe became embroiled in World War II, Japan began to expand into the Southeast Asian colonies of the European powers. After the United States retaliated with economic sanctions, Japan planned a concerted attack on the American naval base at Pearl Harbour, Hawaii, and other Pacific and Asian targets. For a time Japan was master of the central and western Pacific and East Asia.
Japanese Expansion and U.S. Response: 1940-41
Japan's invasion of Manchuria in 1931 and its subsequent full- scale assault against China in 1937 brought expressions of disapproval from the U.S. government. With public opinion strongly isolationist, however, the United States did not act to halt Japanese expansionism. Not until the outbreak of World War II in Europe and the escalation of Japanese aggression did the U.S. response become strong.
In 1940, Nazi Germany's march into Western Europe opened up opportunities for Japan to consolidate its position in China and penetrate Southeast Asia, thereby advancing the Japanese goal of dominating a "Greater East Asia Co-Prosperity Sphere." After the fall of France in 1940, the Vichy government accepted Japanese demands that aid through French Indochina to the Chinese resistance be cut off and that Japan be allowed to use air bases in Indochina. In September, Japanese troops moved into northern Indochina, and Japan joined the Axis. Meanwhile, with Britain fighting for its life and the Netherlands under Nazi occupation, Japan called on the British to close the Burma Road to supplies bound for China and pressed the Dutch East Indies for economic and political concessions. In July 1941, Japan occupied southern Indochina--an obvious prelude to further expansion in Southeast Asia, a rich source of rubber, tin, oil, quinine, lumber, foodstuffs, and other vital raw materials.
References: Footnotes 1. (2000) www.combinedfleet.com. Pacific Naval Battles. 2. (Bidwell et al.) The Encyclopedia of Land Warfare in the 20th Century. (1977). Salamander Books Ltd. 3. (Chant, Davis, Gunston, Humble, Macintyre). The Encyclopedia of Air Warfare. (1977). Salamander Books Ltd. 4. (Harkness, O 'Donaghue). The New Grolier Encyclopedia of World War II • Victory in Japan. (1995). Grolier Educational Corporation. 5. (Donald, D.). Fighters of World War II. (1998). Brown 's Packaging Books Ltd. 6. www.historyplace.com/unitedstates/ pacificwar/timeline.htm 7. www.ww2pacific.com/ww2.html 8. www.geocities.com/pentagon/3758