What Caused Japanese Aggression in World War II?

Nationalist Beliefs

Some intellectuals, and military leaders especially, formed the belief that the Japanese people were racially and ethnically superior to other people and races. 

Many nationalists believed that the Japanese were descendants of the Shinto gods. Propaganda promoted the belief that the Japanese emperors were direct descendants of the Sun Goddess, Amaterasu. 

As a result, Japan believed that it was their destiny to rule Asia, and maybe even the world.

The Sino-Japanese War and the response of Western powers

During the Sino-Japanese war, Japan faced a lack of many materials which were important in the event of War, including oil, rubber, iron, etc. 

Furthermore, although Japan had been able to conquer coastal China with relative ease, the interior was unexpectedly difficult to conquer. This is due to the fact that the Nationalist and Communist armies of China were able to effectively defend the large Chinese interior. 

Furthermore, Japanese aggression towards China had resulted in sanctions and trade embargoes from Western Countries, which were beginning to fear Japan encroaching on their colonies and spheres of influence.

This was dangerous for Japan, as their mainland lacked natural, mineral resources, and they relied on other powers for the trade of raw materials.

Japanese Expansion (The Southern Expansion)

After allying with Germany, Japan began to seize territories that were colonised by their enemies, the British, the French and the Dutch.

Japan simultaneously attacked the Philippines, Hong Kong, Singapore, and Malaya, in a lightning-fast "Southern Expansion".

To sustain the level of resources needed for conflict in China, Japan began to annex territories for supplies.

• Oil fields in Indonesia and Malaya

• Iron ore from Burma, Indonesia and Malaya

• Thailand supplied rubber. 

• The Japanese also took rice and other food supplies from other territories.

The US stance towards Japan

From 1938, the USA had begun a more aggressive policy towards Japan.

In 1938, Roosevelt used his presidential powers to ignore the Neutrality Acts, which treated aggressors and victims equally, and gave more active support to the Nationalists in China. This support included an oil loan of $25 million at first.

By doing so, Roosevelt showed that he did not share the same sentiments of the isolationists.

Sanctions placed on Japan:

• In January 1939, a "moral embargo" (see more) was put in place to restrict the sale of planes and aviation parts to Japan.

• In February 1939, credit to Japan was stopped.

• In July, the 1911 commercial treaty between the United States and Japan was suspended.

• In July 1941, the US froze all Japanese assets after they moved South, rather than Northwards to attack the Soviets.

• In November, the US officially placed a trade embargo, which crucially, included oil.

  • Britain and the Netherlands had placed total trade embargoes on them.

 US aid to China:

• From 1940 to 1941, the USA gave millions of dollars of aid to China as Japanese forces continued to advance.

• After China's supply route with Burma (now known as Myanmar) was closed in October 1941, the USA agreed to increase their loans to China.

• Summer 1941, the US sent 100 P-40 US fighter planes to replenish the Chinese air force.

• The US placed economic pressure on Japan