During 1918 Japan began to become less sufficient, it was short of natural resources, and was not producing enough crops to provide for its population.
By 1931, the party government in Japan had lost its popular support and the military were gaining considerable influence in the country. Japan once more began to follow an aggressive foreign policy on the Asian mainland. Since China was weak, and Manchuria and northern China were rich in mineral resources, Japan saw the answer to their economic problems in the form of a swift invasion. 20,00 troops later entered Manchuria defeating a force of 240,00 of the Chinese army, it was a great victory.
The Great Depression of 1929 hit Japan hard, the effects of this were blamed upon the Japanese Government and as a result, the views of the extremists became highly shared and influential. The army became more powerful and now used intimidation and assassinations as a way of achieving their aims.
The militarist-dominated Imperial Government was followed by the more moderate Hamaguchi government, which tried to curb the power of these military extremists. The extremists responded by plotting to overthrow civilian government. Prime Minister Osachi Hamaguchi was assassinated in 1930 and in March 1931, a coup involving senior military leaders was planned but later abandoned
Japan’s political weakness was now clear and the influence of the Military Extremists increased.
In 1937, Japanese forces invaded Eastern provinces if China, seizing the new capital city, Nanking, and the old capital, Beijing. News reports of atrocities Japanese invaders committed against civilians in the Rape of Nanking horrified the West. Under the leadership of Minister of War Hidek Tojo, Japan’s goal was to establish a defensive perimeter – the “Greater East Asia Co-prosperity Sphere”. By establishing a sphere of influence with Japan in control, Tojo hoped to drive out the Western Powers, raise Japan to a dominate position in Asia and the Pacific, and free Japan from its dependence on Western oil, coal, ore, rubber, and other resources.
Unfortunately, his success was bringing him closer to conflict with those Western Powers.
Concerned about Japanese aggression, the USA, Britain, and the Dutch imposed a trade embargo on Japan cutting off vital supplies of oil and other resources. The USA demanded that Japan declare peace with other countries and stop the war but the Japanese simply blamed the Chinese for the war, saying, “ if only the USA would persuade China to stop fighting all would be well.” Tojo – now Prime Minister – grew convinced that the West’s goal was to encircle Japan and starve it into submission. He ended all diplomatic relations and contact.
Events began to reach boiling point in September 1941, when the US Secretary of State, Cordell Hull demanded that Japan withdraw its troops from the Chinese mainland and from Indo-China. For weeks, Japanese policymakers debated what response to make. Many leaders of the Japanese Imperial Navy quailed at the prospect of going to war with the United States, but Tojo strengthened their resolve by convincing them that to agree to the Americans demands would be a humiliating diplomatic defeat, once again reducing Japan to the status of a minor nation. While carrying on negotiations with the USA, Japan sent its army into Thailand, Malaya, Burma, and the East Indies. And on November 26th, 1941, the Japanese Navy set sail for Pearl Harbour; the base in the Hawaiian Islands where most of the U.S Pacific fleet was docked.