And tons of foreign interference, more than just the Japanese, over the huge expanse of China-a few examples. In 1946:
The United States strongly supported the Kuomintang forces. Over 50,000 Marines were sent to guard strategic sites, and 100,000 US troops were sent to Shandong. The US equipped and trained over 500,000 KMT troops, and transported KMT forces to occupy newly liberated zones, as well as to contain Communist controlled areas. American aid included substantial amounts of both new and surplus military supplies; additionally, loans worth hundreds of millions of dollars were made to the KMT. Within less than 2 years after the Sino-Japanese War, the KMT had received 4.43 billion dollars from the US - most of which was military aid
In addition, the Ili Rebellion was a Soviet backed revolt by the Second East Turkestan Republic against the KMT from 1944-1949 as the Mongolians in the People's Republic were in a border dispute with the Republic of China. A Chinese Muslim Hui cavalry regiment, the 14th Tungan Cavalry regiment, was sent by the Chinese government to attack Mongol and Soviet positions along the border during the Pei-ta-shan Incident.
And naval invasions:
A PRC attempt to take the ROC controlled island of Quemoy was thwarted in the Battle of Kuningtou halting the PLA advance towards Taiwan. In December 1949, Chiang proclaimed Taipei, Taiwan, the temporary capital of the Republic of China and continued to assert his government as the sole legitimate authority in China.
The Communists' other amphibious operations of 1950 were more successful: they led to the Communist conquest of Hainan Island in April 1950, capture of Wanshan Islands off the Guangdong coast (May–August 1950) and of Zhoushan Island off Zhejiang (May 1950).
Bet it would be a fascinating AGEOD game. So do we have any Chinese History experts with modding abilities out there? I suspect it would only take a couple few years to follow in the footsteps of the Espania modders and come up with China Under Siege.