More than two years before German tanks bombed Poland and four years before the Japanese bombed Pearl Harbor, what some historians consider the start of World War II happened in China in 1937. The country’s eight years with Japan sowed the seeds for the attack on Pearl Harbor, but ultimately contributed to Allied victory in the Pacific, at an incredibly high price for the Chinese.
Sino-Japanese Relations Before World War II
For decades after the First Sino-Japanese War in 1894-1895, China and Japan remained uneasy neighbors. As China is engulfed in a civil war between the ruling Chinese Nationalist Party of Chiang Kai-shek and the communist forces of Mao Zedong, the Imperial Japanese Army invades the resource-rich region of Manchuria in the northeast of China in 1931 and installed a puppet government.
An imperialist Japan further encroached on northern China in the years that followed as the Nationalist government continued to view Mao’s communist fighters as a greater threat. It was only after Communist generals held Chiang for two weeks in December 1936 that he reluctantly agreed to an uneasy alliance with Communist forces against Japan.
As tensions with China rose, on July 7, 1937, Japanese soldiers conducted nighttime training exercises 10 miles (16 km) southwest of Beijing, near a stone bridge named after the 13andMarco Polo, Venetian merchant of the last century. After Japanese soldier Shimura Kikujiro failed to return to base after becoming lost in the dark following an unscheduled restroom break, Chinese guards denied Japanese entry into the city. adjacent Wanping to search for their missing comrade. The clash turned violent, and what became known as the Marco Polo Bridge Incident proved the spark that ignited the Second Sino-Japanese War.
The Second Sino-Japanese War

Japanese troops enter the Chinese province of Shanxi in 1937, during the Second Sino-Japanese War.
Ullstein bild/ullstein bild via Getty Images
Within weeks, the technologically superior Japanese forces seized Beijing. They captured the commercial center of Shanghai in November 1937, but the fierce battle it demanded made it clear that China intended to mount a resolute defense.
The Imperial Japanese Army responded to Chinese resistance with increasingly brutal atrocities, the most notorious of which occurred after it entered the Chinese Nationalist capital of Nanjing (or Nanjing) in December 1937. Over a period of six weeks, the Japanese military massacred between 200,000 and 300,000 soldiers and civilians and sexually assaulted tens of thousands of women.
As Japan pushed south and west in 1938, a Chinese defeat seemed inevitable. “They don’t have allies, they don’t have weapons, and they retreated inside China,” says Rana Mitter, author of Forgotten Ally: China’s Second World War, 1937-1945. “Chinese nationalists and communists are on the run.”
The war, however, increasingly turned into a stalemate, with Japanese forces making little progress beyond port cities and urban areas south of Beijing. Communists in north-central China waged guerrilla warfare against the Japanese in Manchuria and northern China, and the fragile truce with the Nationalists was maintained.
Allied powers start backing China as war in Europe takes off

A 1943 poster for United China Relief, an American organization founded to support China after the Second Sino-Japanese War.
Universal History Archive/Universal Pictures Group via Getty Images
Foreign aid began to flow to China as Japan stagnated. Soviet dictator Joseph Stalin saw a victorious Japan as such a threat to the USSR that he supplied Chinese nationalists with weapons, despite their battles with the Communists. In 1940 and 1941, US President Franklin D. Roosevelt extended credit to China to purchase military supplies and included the country in the Lend-Lease program. In August 1941, the United States further hampered Japan’s ability to fight in China by stopping its trade in aircraft, oil and scrap metal, an embargo which was one of the reasons Japan attacked Pearl Harbor .
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If China had surrendered in 1938 as planned, the entire trajectory of World War II would have changed, according to Mitter. “The escalation that Japan had to go through in the following years because of Chinese resistance would never have happened. That means no Pearl Harbor because without the escalation of Japanese attacks on China, you won’t have the desperate thirst for resources that eventually leads to the oil embargo and the decisions of President Roosevelt in 1940 and 1941. And if you don’t have Pearl Harbor, you don’t have an Asian war that can then be joined to the war European.
READ MORE: FDR, Churchill and Stalin: Inside their uneasy WWII alliance
The United States and China have become allies
After the United States and the United Kingdom joined the fight against Japan after Pearl Harbor, the flow of equipment, money and military advisers to China increased along with its global stature. Roosevelt considered China one of the “four policemen” of the world along with the Americans, British and Soviets and one of the cornerstones of a new world order that would emerge after the war.
As American bombers used Chinese airbases to strike Japanese targets, the Chinese continued to shoulder the burden of the ground war as Allied attention initially remained focused on Europe. Now facing a wider war, the Japanese army remains mired in China with between 500,000 and 600,000 troops, according to Mitter, and 38 of the 51 infantry divisions stationed in the country.
Japan gained ground and seized airbases in its “Ichi-Go” offensive in 1944, but China repelled two Japanese offensives in the summer of 1945. After the Soviet Union entered the war and overwhelmed Japanese positions in Manchuria, the United States dropped atomic bombs on Hiroshima and Nagasaki, Japan surrendered.
China after World War II
The war has left an incredible scale of devastation. According to Mitter, historians have calculated that the war forced 100 million Chinese, about one-sixth of the country’s population, to become refugees in their own country, and only the Soviet Union exceeded the death toll of the war. World War II in China.
“Reliable numbers go up to 12 or 14 million and in some cases up to 20 million,” says Mitter. That tally includes hundreds of thousands of deaths from drowning, disease and starvation after the Chinese Nationalist army drilled huge holes in the levees holding back the Yellow River to thwart the Japanese advance in 1938. Millions more died after Chiang’s decision to seize grain from peasants for food. the military exacerbated a famine in Henan Province in 1942 and 1943.
The Japanese surrender, however, did not mean the end of the war in an exhausted China. The country’s civil war resumed and led to Mao’s Communist Revolution which overthrew the Nationalist government of Chiang Kai-shek in 1949. As China and the United States turned from friends to foes, the public memory of the China’s role as a member of the Allies has faded on both sides of the Pacific.
“After 1949, when Mao and the Communists took over the mainland, the only thing that became quite unacceptable, certainly at the central level, was something positive to say about Chiang Kai-shek’s regime,” says Mitter. . “During the High Cold War, the West and China had strong motivations not to revisit history, and so for more than a quarter of a century it remained essentially in the shadow of historiography.”
