The revolution led by the Kuomintang (KMT, or Chinese Nationalist Party) and others ended the last Chinese dynasty, the Qing dynasty, which was replaced by a republic, the Republic of China, in 1912. Prior to World War I, however, the ROC central government failed to effectively rule its territory. China fell into a fragmented region of local warlords. Other than the warlord-controlled central government, two primary forces aimed to unite China under their ideology. The KMT was reorganized in 1919, and the Chinese Communist Party was formed in 1921. The two parties were not immediate enemies and had short-term partnership. In 1924, KMT started a military campaign to defeat the northern warlords. In 1927, with much of southern and central China under the KMT control, the KMT openly turned on the CPC. The KMT took most parts of China under its power in 1928, and the warlord controlling Manchuria agreed to KMT leadership of Generalissimo Chiang Kai-shek.
The following events played a significant role in setting the stage for the involvement of Asia and the Pacific in World War II:
1858: Western nations force Japan to sign the Unequal Treaties. These articles established export and import tariffs and the concept of "extraterritoriality" (i.e. Japan held no jurisdiction over foreign criminals in its land. Their trials were to be conducted by foreign judges under their own nation's laws). Japan had no power to change these terms.
1868: Japan, in an effort to modernize and prevent future Western dominance, ousts the Tokugawa Shogunate and adopts a new Meiji Emperor. The next few decades see arguably the most rapid and successful industrialization of any economy in world history during the Meiji Restoration.
Many historians argue that World War II began with the Marco Polo Bridge Incident on July 7, 1937. While other historians believe the war began with the Mukden Incident in Manchuria on September 18, 1931. Japanese occupation of much of Asia would last until 1945.
January 28, 1932: The January 28 Incident: fighting erupts between Chinese boycotters and Japanese troops protecting the Japanese section of Shanghai. The Japanese dispatch a naval invasion force in an attempt to capture Shanghai. However, the invasion ended in a stalemate. United Kingdom and United States broker a cease-fire between China and Japan three months after the hostilities begin.
February, 1932: Manchukuo is announced as an independent nation, in reality a Japanese puppet government for Manchuria. It encompassed the three northeastern Chinese provinces occupied by Japan since the "9.18 Incident." Japanese control remains direct however, and Japanese owned interests gain considerable power. Additionally, the opium trade is encouraged. Manchukuo was not recognized by the League of Nations and Japan subsequently withdraws from the organization.
May, 1932 May 15 incident: Japanese Prime Minister Inukai Tsuyoshi assassinated by a group of young officers for his support of the London Naval Treaty, which is seen in Japan as preventing parity of forces.
November, 1936: Japan joins Germany in signing the Anti-Comintern Pact, concluded to provide a two-front threat to the Soviet Union. Japan is however not interested in being drawn into a European war, and thus the pact is not a true alliance.
July 7, 1937: Marco Polo Bridge Incident. Japanese forces conducting military exercises outside Peking claimed that several Japanese soldiers were not accounted for after the exercise. Japanese launch an all-out assault. Nanking government declares its intent to resist Japan, marking the start of the Second Sino-Japanese War. (Note: For political reasons, war was not declared by either side at this point. The Chinese declaration of war came on December 8, 1941).
August–November 1937: Full-scale fighting erupts throughout northern China, and Japan overcomes initial failures with landings and reinforcements in Shanghai. Before the Battle of Shanghai, the Tokyo government announced that Japan would complete the conquest of Shanghai in three days, and all of China within three months. KMT troops held Shanghai for over three months.
Chinese soldiers poorly armed.
December 1937: Nanjing Massacre that city is captured and subjected to months of the rampage. The Rape of Nanking resulted in the deaths of up to 300,000 Chinese civilians. This is in line with the Three Alls Policy: kill all, burn all, loot all.
April, 1938: Chinese Nationalists gain a major victory over Japanese forces in Shantung province.
June, 1938: The Japanese advance along the Yellow River is halted by the breaking of dams by the Chinese. The surprise flood kills many Japanese but also as many as 1,000,000 civilians.
July, 1938: Japanese forces provoke a battle with the Soviets at Lake Hassan in Manchukuo. The Soviets handily defeat the Japanese.
April, 1941: American volunteer pilots secretly recruited in U.S. Their first actual combat will be in December 1941 in Burma where they will begin to wreak havoc upon Japanese forces and will soon be named the Flying Tigers.
August, 1941: The United States, which at the time supplied 80% of Japanese oil imports, initiates a complete oil embargo. This threatens to cripple both the Japanese economy and military strength once the strategic reserves run dry, unless alternative oil-sources can be found.