Japanese invasion of China (1937–1945)

Japanese invasion of China (1937–1945)
Conflict	Second Sino-Japanese War
Caption	Marco Polo Bridge Incident site, July 1937
Date	July 7, 1937 – September 9, 1945
Place	China, Manchuria, Taiwan, East China Sea
Result	Japanese surrender; Republic of China restored control over occupied territories; Chinese Civil War resumed
Combatant1	Empire of Japan, Manchukuo, Mengjiang
Combatant2	Republic of China, Chinese Communist Party, United States, Soviet Union, United Kingdom
Commander1	Hirohito, Hideki Tojo, Kōki Hirota, Prince Fumimaro Konoe
Commander2	Chiang Kai-shek, Zhou Enlai, Mao Zedong, He Yingqin
Casualties	Estimates vary: millions military and civilian

Contents

Japanese invasion of China (1937–1945)

The conflict beginning with the Marco Polo Bridge Incident in July 1937 expanded into a full-scale war between the Empire of Japan and the Republic of China, drawing in the Chinese Communist Party, the United States, the Soviet Union, and the United Kingdom. The war encompassed major campaigns, atrocities such as the Nanjing Massacre, and strategic interactions with the Pacific War, culminating in Japan's surrender in September 1945 and profound effects on East Asia and the postwar international order.

Background and origins

By the early 1930s the Empire of Japan had consolidated influence over Manchuria through the Mukden Incident and the creation of Manchukuo, provoking condemnation from the League of Nations and rivalry with the Republic of China leadership of Chiang Kai-shek. Japanese expansionism was shaped by figures such as Yoshiko Shimuzu and policymakers in the Imperial Japanese Army, including Prince Kan'in Kotohito, while Chinese politics were fractured between the Kuomintang and the Chinese Communist Party, led by Mao Zedong and Zhou Enlai. International responses involved the United States Department of State, the British Foreign Office, and the Soviet Politburo, with contentious debates at the Washington Naval Conference era and arms transfers through actors like Soviet–Chinese Non-Aggression Pact discussions and American support channels exemplified by Soong Mei-ling's diplomacy.

After clashes at the Marco Polo Bridge, Japanese forces under commanders such as Iwane Matsui and Shunroku Hata launched operations against Beiping and Tianjin, culminating in the capture of Shanghai after the Battle of Shanghai (1937), the Battle of Taiyuan, and the Battle of Nanjing, where units of the Imperial Japanese Army perpetrated the Nanjing Massacre overseen by officers like Iwane Matsui and political figures including Hideki Tojo. The fall of Wuhan and the establishment of Wang Jingwei's Reorganized National Government of the Republic of China in Nanjing (capital) signaled Japanese attempts at collaboration, while Chinese retreat to Chongqing under Chiang Kai-shek preserved a wartime capital. Diplomatic maneuvers included appeals to the League of Nations and negotiations involving Joseph Stalin's envoys and American representatives such as Franklin D. Roosevelt.

The entry of the United States into the Pacific War after Attack on Pearl Harbor transformed the theater, linking campaigns in China with operations in Burma, Philippines, and Dutch East Indies. Japanese strategy leveraged resources from Manchukuo and Taiwan (Formosa) while confronting supply interdiction by the Flying Tigers—the American Volunteer Group organized by Claire Lee Chennault—and Lend-Lease aid routed via the Burma Road and Hump (airlift). Soviet offensives in August 1945 from the Transbaikal Front against the Kwantung Army and Allied operations involving Admiral Ernest King and General Joseph Stilwell pressured Japanese positions until Emperor Hirohito accepted the Instrument of Surrender following the Atomic bombings of Hiroshima and Nagasaki.

Japanese occupation policies combined military administration by units such as the Kwantung Army and civilian control via the South Manchuria Railway Company, enforced by secret police like the Kempeitai. Atrocities included the Nanjing Massacre, biological warfare conducted by Unit 731 under Shirō Ishii in Harbin and Pingfan, and the Three Alls Policy (Sankō Sakusen) executed during anti-guerrilla campaigns. Forced labor programs exploited populations in Manchukuo, Shanghai International Settlement zones, and occupied provinces; sexual slavery occurred through the comfort women system administered by Japanese military bureaus. War crimes trials postwar addressed perpetrators via the International Military Tribunal for the Far East and Chinese tribunals in Nanjing and Shanghai.

Chinese resistance combined Nationalist conventional forces under Chiang Kai-shek with Communist guerrilla warfare directed by Mao Zedong, Zhu De, and Peng Dehuai; the Second United Front was a formal but uneasy cooperation between Kuomintang and Chinese Communist Party units. International assistance arrived through the Soviet Union's early aid and Sino-Soviet Non-Aggression Treaty-adjacent support, American Lend-Lease material, and volunteer efforts like the Flying Tigers. Allied coordination involved figures such as Winston Churchill in strategic conferences at Cairo Conference and Tehran Conference with implications for Burma Road logistics and the Allied Pacific Strategy.

Major engagements included the Battle of Shanghai (1937), the Battle of Nanjing, the Battle of Wuhan, the Battle of Changsha (1939–1942), the Battle of Chongqing (air raids), the Battle of Taiyuan, and the Battle of South Guangxi. Campaigns in Sichuan and Hubei featured protracted sieges and blockades; counteroffensives like Operation Ichi-Go aimed to secure rail links between Manchuria and French Indochina. The Battle of West Hubei and the Battle of Changde exemplified large-scale conventional clashes, while guerrilla actions in Hebei, Shandong, and Guangxi disrupted Japanese supply lines and tied down the Imperial Japanese Army.

Japan's surrender in September 1945 reunited occupied territories with the Republic of China but left unresolved tensions that precipitated the resumption of the Chinese Civil War between the Kuomintang and the Chinese Communist Party, culminating in the proclamation of the People's Republic of China in 1949. Postwar justice via the Tokyo Trials and Chinese tribunals sought accountability for crimes by figures such as Shirō Ishii and Iwane Matsui, while issues like reparations, recognition of comfort women, and historical memory continue to affect Sino-Japanese relations and regional diplomacy with states including the United States and Republic of Korea. The war reshaped geopolitics across East Asia, influenced the decolonization of Southeast Asia, and informed postwar institutions like the United Nations.