Second Sino-Japanese War

The Second Sino-Japanese War (1937–1945) or War of Resistance (Chinese term)[lower-alpha 1] was a military conflict primarily between the Republic of China and the Empire of Japan. The war made up the Chinese theater of the wider Pacific Theater of the Second World War. The beginning of the war is conventionally dated to the Marco Polo Bridge Incident on 7 July 1937, when a dispute between Japanese and Chinese troops in Beijing escalated into a full-scale invasion. Some Chinese historians consider the start of the war as the Japanese invasion of Manchuria on 18 September 1931. China was aided by the Soviet Union, the United Kingdom, the United States, and Nazi Germany before its alliance with Japan. Around 20 million people, mostly civilians, were killed.

Second Sino-Japanese War
Part of the Pacific theatre of World War II
Clockwise from top left: Imperial Japanese Navy landing force in military gas masks in the Battle of Shanghai Japanese Type 92 heavy machine gunners during Operation Ichi-Go Victims of the Nanjing Massacre on the shore of the Qinhuai River Chinese machine gun nest in the Battle of Wuhan Japanese Mitsubishi Ki-21 bomber during the bombing of Chongqing Chinese Expeditionary Force marching in India
Date 7 July 1937[lower-alpha 1] – 2 September 1945 (8 years, 1 month, 3 weeks and 5 days) Location Mainland China, Indochina and Burma Result Chinese victory[lower-alpha 2] Surrender of Japanese forces in mainland China (excluding Manchuria), Taiwan, and French Indochina north of 16° north to the Republic of China after losing territory to China[1] China as one of the Big Four Allies China becomes permanent member of the UN Security Council Resumption of the Chinese Civil War Consolidation of power for nationalist government, most local warlords annexed by Chinese Central Government Territorial changes China recovers all territories lost to Japan since the Treaty of Shimonoseki.
Belligerents
China[lower-alpha 3] Nationalists Communists Foreign support:  Germany (1937–1938)  Soviet Union (1937–1941)  United States (1941–1945)  British Empire (1942–1945)	Japan Collaborator support:  Manchuria (1937–1945)  Inner Mongolia[lower-alpha 4] (1937–1945) East Hebei[lower-alpha 5] (1937–1938) Provisional Government[lower-alpha 6] (1937–1940) Reformed Government[lower-alpha 7] (1938–1940) Nanjing Nationalist Government (1940–1945)
Commanders and leaders
Chiang Kai-shek He Yingqin Chen Cheng Cheng Qian Bai Chongxi Xu Yongchang Li Zongren Wei Lihuang Yan Xishan Xue Yue Gu Zhutong Fu Zuoyi Zhang Fakui Sun Lianzhong Mao Zedong Zhu De Peng Dehuai Foreign commanders: A. von Falkenhausen Aleksandr Cherepanov Joseph Stilwell Albert Wedemeyer Claire Lee Chennault Milton E. Miles	Emperor Hirohito Shunroku Hata Yasuji Okamura Prince Kotohito Otozō Yamada Hajime Sugiyama Toshizō Nishio Hisaichi Terauchi Hayao Tada Iwane Matsui Seishirō Itagaki Hideki Tōjō Rikichi Andō Kenkichi Ueda Naozaburo Okabe Collaborators: Puyi Zhang Jinghui Demchugdongrub Wang Kemin Liang Hongzhi Wang Jingwei Chen Gongbo Zhou Fohai
Strength
14,000,000 total Chinese Nationalists: (including regional warlords): 1,700,000 (1937) 2,600,000 (1939)[2] 5,700,000 (1945)[3] Chinese Communists: 640,000 (1937)[4] 166,700 (1938)[5] 488,744 (1940)[6] 1,200,000 (1945)[7]	4,100,000 total[8] Japanese: 600,000 (1937)[9] 1,015,000 (1939)[10] 1,124,900 (1945)[11] (excluding Manchuria and Burma campaign) Puppet states and collaborators: 900,000–1,006,086 (1945)[12] [13]: 314
Casualties and losses
Nationalists: Official ROC data: 1,320,000 killed 1,797,000 wounded 120,000 missing Total: 3,237,000[14][15] Other estimates: 3,000,000–4,000,000+ military dead and missing 500,000 captured[16][17] Total: 3,211,000–10,000,000+ military casualties[17][18] Communists: Official PRC data: 160,603 military dead 290,467 wounded 87,208 missing 45,989 POWs Total: 584,267 military casualties[19] Other estimates: 446,740 total[18] Total: 3,800,000–10,600,000+ military casualties after July 1937 (excluding Manchuria and Burma campaign) 1,000,000+ captured[16][17] 266,800–1,000,000 POWs dead[16][17]	Japanese: Japanese medical data: 455,700[20]–700,000 military dead[21][lower-alpha 8] 1,934,820 wounded and missing[22] 22,293+ captured[lower-alpha 9] Total: 2,500,000+ military casualties (1937 to 1945 excluding Manchuria and Burma campaign) Puppet states and collaborators: 288,140–574,560 dead 742,000 wounded Middle estimate: 960,000 dead and wounded[23][24] Total: c. 3,000,000–3,600,000 military casualties after July 1937 (excluding Manchuria and Burma campaign)[lower-alpha 10]
Total casualties: 15,000,000[25]–22,000,000[15]
Minor clashes since September 18, 1931 Part of the Allied victory in the Pacific War The Nationalist Government led a united front between the Nationalists (and allied warlords) together with Communists. The Mongol United Autonomous Government, established in 1937, merged with the Autonomous Governments in South Chahar and North Shanxi, both formed in the early stages of the war, to create the Mengjiang United Autonomous Government in 1939. Mengjiang nominally became an autonomous territory of the Nanjing Nationalist Government from 1940 onward, but was de facto independent from it. The East Hebei Autonomous Government, created in 1935, was absorbed by the "Provisional Government" in Northern China in 1938. The "Provisional Government" established in northern China became part of the new Nationalist central government in Nanjing in 1940, but continued to enjoy de facto autonomy within it. The "Reformed Government" established in central China was succeded by the new Nationalist central government in Nanjing in 1940. This number does not include Japanese killed by Chinese forces in the Burma campaign and does not include Japanese killed in Manchuria. Excluding more than 1 million who were disarmed following the surrender of Japan Including casualties of Japanese puppet forces. The combined toll is most likely around 3,500,000: 2.5 million Japanese, per their own records, and 1,000,000 collaborators.

This full-scale war between China and the Empire of Japan is often regarded as the beginning of World War II in Asia, although some scholars consider the European War and the Pacific War to be entirely separate, albeit concurrent. The Second Sino-Japanese War was the largest Asian war in the 20th century,[26] and it has been called "the Asian holocaust."[27][28][29] After the Japanese attacks on Malaya and Pearl Harbor in 1941, the war merged with other conflicts which are generally categorized under the China Burma India Theater of World War II.

In 1931, the Mukden Incident was the pretext for the Japanese invasion of Manchuria. The Chinese were defeated and Japan created a new puppet state, Manchukuo; many historians consider this the beginning of the Second Sino-Japanese War.[30][31] From 1931 to 1937, China and Japan continued to skirmish in small, localized "incidents".

Following the Marco Polo Bridge Incident, the Japanese scored major victories, capturing Beijing, Shanghai and the Chinese capital of Nanjing in 1937, which resulted in the Rape of Nanjing. After failing to stop the Japanese in the Battle of Wuhan, the Chinese central government relocated to Chongqing (Chungking) in the Chinese interior. Following the Sino-Soviet Treaty of 1937, strong material support helped the Nationalist Army of China and the Chinese Air Force continue the fierce resistance against the Japanese offensive.

By 1939, after Chinese victories in Changsha and Guangxi, and with Japan's lines of communications stretched deep into the Chinese interior, the war reached a stalemate. While Japan ruled the large cities, they lacked sufficient manpower to control China's vast countryside. The Japanese were unable to defeat Chinese Communist Party (CCP) forces in Shaanxi, who waged a campaign of sabotage and guerrilla warfare against the invaders. However Japan ultimately succeeded in the year-long Battle of South Guangxi, occupying Nanning and cutting off the last sea access to the wartime capital of Chongqing. In November 1939, Chinese nationalist forces launched a large scale winter offensive, while in August 1940, CCP forces launched an offensive in central China. The United States supported China through a series of increasing boycotts against Japan, culminating with cutting off steel and petrol exports to Japan in June 1941. Additionally, American volunteers such as the Flying Tigers fought for China directly.

In December 1941, Japan started war with the Netherlands, United Kingdom and the United States. The US increased its flow of aid to China: the Lend-Lease act gave China a total of $1.6 billion ($20.19 billion 2023).[32] With Burma cut off, the US Air Force airlifted material over the Himalayas. In 1944, Japan launched Operation Ichi-Go, the invasion of Henan and Changsha. However, this failed to bring about the surrender of Chinese forces. In 1945, the Chinese Expeditionary Force resumed its advance in Burma and completed the Ledo Road linking India to China. At the same time, China launched large counteroffensives in South China and repulsed a failed Japanese invasion of West Hunan and recaptured Japanese occupied regions of Guangxi.

Japan formally surrendered on 2 September 1945, following the Soviet invasion of Manchuria. China was recognized as one of the Big Four Allies during the war, regained all territories lost to Japan, and became one of the five permanent members of the United Nations Security Council.[33][34] The Chinese Civil War resumed in 1946, with the Chinese Communist Party consequently gaining the upper hand with help from the Soviets, and ultimately ending with a communist victory, which established the People's Republic of China.