The Qing Imperial Monarchy was ultimately toppled by a decentralized revolution. Once it had been overthrown, it proved hard to find a new governmental structure that was satisfactory to all the regional economic and political interests which had worked to depose the Manchus.
Despite having only 53 members in 1921, the Chinese Communist Party (CCP) membership consistently expanded through 1928 by giving voice to workers and peasants. That said, during this time Sun Yat-sen’s Kuomintang Party (KMT), also referred to as the Guomindang or Nationalist Party, continued to enjoy greater prestige and numbers.
The period between 1927 and 1937 is often referred to as the Nanjing decade. The Kuomintang (KMT) established its new government in Nanjing after it had dispelled the Communists from the United Front and it had defeated the warlords to unite the country during the Northern Expedition.
The Second United Front - that was to fight Japanese expansion in China – worried Japanese militarists who increasingly controlled Japanese domestic and foreign policy. They argued that Japan should strike against China before it became too strong.
On August 6 and August 9 the Americans dropped atomic bombs on Hiroshima and Nagasaki. By August 14 the Japanese surrendered, bringing to an abrupt end the 1937-1945 Sino-Japanese War and WWII into which the Sino-Japanese War had been subsumed.