The Split of China occurred when the Japanese won the Second Sino-Japanese War. On April 22 1938, China was split up into two independent states, two puppet states of Japan and one colony of Japan. The British and Portuguese colonies in China remained unaffected.
China had been at war for a while with Japan. Japan had succeeded in controlling most of the northern part of the Republic of China, which was also involved in a civil war. On the 16 April 1938, the Japanese army launched an assault on a major Chinese base, destroying around half of the Chinese forces. two days later, the Republic of China officially surrendered to the Empire of Japan. The Emperor of Japan immediately got his advisers to draw up plans to split the country. The country was then split into the independent nations of Tibet and Sinkaing. (Two autonomous regions of the former country which wanted freedom.) Then the remaining land was given to the puppet states of Manchuria and Manchukuo. The territory left over was the formed into a Japanese colony.