1936: The Sino-Japanese War
The Japanese Invasion of Manchuria:
In 1931, the Japanese invaded the Northern Chinese province of Manchuria, claiming that the Chinese had sabotaged a section of a railway owned by them. By 1932, they were able to conquer the region, and renamed it Manchukuo.
Chiang took little action to stop them due to the fact that he was pre-occupied with the threat of the CCP. He actually ordered people not to resist the Japanese as he feared a full-scale invasion.
In fact, Chiang subsequently signed the Tanggu Truce in May 1933 which certified Japanese ownership over the area.
Despite the truce, Japanese raids into China continued.
Chiang attempted to justify his lack of response to the threat of Japan by saying "The Japanese are a disease of the skin, it can be cured. The Communists are a disease of the soul; it affects the whole body"
He believed that national unity had to be achieved before attacking the Japanese.
However, people were furious that he had not stood up to Japanese aggression and responded to the invasion of Manchuria.
Six months after the 1936 Xi’an incident, the Japanese carried out a further Invasion of China.
Despite the United Front, the Japanese armies were able to invade China easily. This is because they were more well-equipped with more advanced and modern weapons.
In July 1937, the Japanese troops attacked the Chinese troops at the Marco Polo Bridge, near the previous dynastic Capital City of Beijing (served as Capital from 1421 to 1912 upon the collapse of the Qing Dynasty). This was the beginning of full-scale war which lasted until 1945.
Weakness in the Nationalist government made it easy for the Japanese to continue their conquests. Meanwhile, the Communists relied heavily on less effective guerrilla tactics. In doing so, they were able to delay the Japanese expansion to a certain extent.
Nationalist retreat to Sichuan
By the beginning of 1938, 1 million Japanese troops had occupied many of China's ports, industrial and commercial areas and major cities.
As a result, Chiang Kai Shek and the Kuomintang retreated to the mountainous province of Sichuan.
By 1939, the extent of control that Japan had over China was vast, although, Japan lacked influence to the whole of China and the empire had many limits.
One reason is because the country was large, so they were unable to control it. Furthermore, they were particular about holding onto large cities, such as those with ports and airfields, rather than holding control over the entire country.
This allowed the Chinese to move back into some areas and take control of the countryside.
Overall, the War significantly benefitted the CCP.
Prior to the full-scale invasion in 1937, the Communists only controlled a 77,700 km2 area which was inhabited by 2 million people, whereas, by 1945, they controlled a 777,000 km2 area inhabited by 95 million people.
During the Sino-Japanese War / WW2, there was a break of full-scale Civil War in China as they focused on fighting the Japanese, however, it resumed following the defeat of Japan.
By 1949, the Communist Party was able to defeat Chiang Kai Shek and the Kuomingtang, forcing them to retreat to the island of Formosa, establishing the Nationalist Government of Taiwan.