The causes of World War Two in Asia were very different from the causes of World War Two in Europe. World War Two in Europe was caused by German anger over the Versailles Treaty. The cause of World War Two in Asia was the combination of Chinese weakness because of a long-running civil war and growing Japanese strength and need for natural resources.
Chinese Revolution in 1911 that overthrew the Qing Dynasty and sparked a civil war over the type of government should have. The revolutionary forces in China were unable to organize a new government and the country. The result was that China was ruled by warlords controlled different parts of the country with their own private armies. In these condition, the leader Sun Yat-sen organized the Koumintang (KMT) to take over China and turn it into a modern republic following the Western model based on individual rights, democracy and capitalism. However, in 1919, the Versailles Treaty gave Japan control of the parts of China that had been run by Germany. This set off a set of protests in China called the Fourth of May Movement in which Chinese reformists turned away from the Western Democratic model because it was viewed as imperialistic. Instead, Sun turned to the newly established Soviet Union for assistance in building the KMT army in return for allowing a communist movement to begin organizing in China. The Soviet support helped the KMT build a strong army and take over China in 1927. However, by this time, Sun was dead and his successor Chiang Kai-shek opposed communism and massacred the Chinese communists. The Chinese communist leader Mao Zedong survived the massacre by hiding in the rural countryside where he began to build a peasant communist army. In 1933, Chiang tried to destroy the Mao's communist army, but Mao was able to save it by retreating to the far north of China in an event called the Long March.
In contrast to China, Japan emerged from World War One being very interested in Western culture and becoming more liberal. However, Japan was confronted by the difficulty it had in building it modern industrial economy with limited natural resources, like oil, coal and iron. This lead to a struggle in Japan as its liberal government came into conflict with Japanese military and industry that looked to the rest of Asia as a source of natural resources for its economy. This conflict resulted in the military and industry taking over the country so as to build a larger Asian empire to secure resources for the Japanese economy. After this, Japan began to expand into northern China. Chiang Kai-shek ignored Japanese expansion to focus on destroying Mao's communists. Similar to Nazi aggression in Europe, Chiang's inaction to Japanese aggression had the effect of further encouraging Japanese expansion.
World War Two in Asia began in 1937 when Japan invaded and conquered all of coastal China, pushing Chiang's KMT government into the interior of China. After capturing coastal China, in 1941, the Japanese continued to expand southward to conquer the European colonies in South East Asia and Indonesia. At this point, the Japanese attacked the United States naval base at Pearl Harbor because it was the only power that could challenge Japan's ambitions for building a Pacific Empire. This event brought the United States into World War Two. While Japan portrayed itself as fighting Western Imperialism, in reality it treated the conquered people in its empire similar to way its Nazi allies treated the conquered people in Europe. It is estimated that 15 million Chinese people were killed during World War Two - the only country to lose more people was the Soviet Union. The brutality of the Japanese occupation of China resulted in Chiang Kai-shek and Mao Zedong forming an uneasy alliance of the KMT and communist forces against the Japanese.
After the Japanese attack on Pearl Harbor in 1941, the United States and Japan fought a naval war across the vast expanses of the Pacific Ocean. Over the course of the war, the United States began to move island by island across the Pacific closer to Japan while at the same time bombing the cities of Japan. As the United States closed in on Japan, the Japanese soldiers and civilians put up a suicidal defense against the American forces. At the same time, the United States tested the first atomic bomb and made the decision to drop it on Japan as a way of ending the war. In August 1945, the United States dropped two atomic bombs on Japan and Japan surrendered unconditionally to the United States.
Source # 1 - Japanese War In China - click here (available on BHS Google Docs here)
Source # 2 - Clip from the movie Children of Huang Shi - The movie is based on the real life story of British journalist George Hogg who was in China and witnessed the Japanese occupation of Nanjing (Nanking) - click here
Note - You will have to be logged into your BHS Google Account to watch the video
Source # 3 - Air Raid on Tokyo - click here (available on BHS Google Docs here)