At the beginning of the 20th century China faced great political and social instability. The country suffered flooding and droughts that caused mass famine. Along with losing wars to Russian, Japan and the Eight-Nation Alliance during the Boxer Rebellion. Public trust in the Qing dynasty's ability to rule the country was eroded and resulted in several uprisings, culminating in the Xinhai Revolution which overthrow the monarchy, establishing the Republic of China and ended 4,000 years of imperial rule in China.

Yuan Shikai was appointed the first president of China, his death in 1916 left a power vacuum that fragmented the country with various warlords taking control of different provinces. During the 1920's the Kuomintang and Chinese Communist Party launched the Northern Expedition together, using military force and political negotiation to reunified the country. The two groups distrusted each other though and soon split apart starting the first Chinese Civil war in 1927.

In December 1941 Japan attacked the American naval base at Pearl Harbor, bringing the United States into World War 2. Following this America began supplying the Chinese forces with equipment for their fight against Japan. Because Japan held all the major ports along China's east coast, Allied supplies had to be brought in from the west, at first through Burma and then through India and over the Himalayan Mountains.

Bolstered by the Allied supplies the Chinese forces managed to stop the Japanese advancement at the Battle of Changsha in January 1942. Chinese forces were also sent to Burma to help the British and India troops resisting the Japanese invasion. Most notable is the Battle of Yenangyaung where 7,000 British troops were encircled by Japanese forces, Chinese troops launched an attack against the Japanese opening up a gap in the lines, allowing the British to forces to retreat.

Chinese troops went on to play a vital role in pushing Japanese forces out of northern Burma, securing the vital Allied supply route. Plans were drawn up to begin the liberation of southern China from Japanese occupation forces but the war against Japan ended with the dropping of the atomic bombs and the Soviet invasion of Manchuria.