Lesson 22: War, Occupation and Resistance, 1937–1945

On 7 July 1937, fighting at the Marco Polo Bridge near Beijing escalated into full-scale war between China and Japan. The war that followed — known in China as the War of Resistance against Japanese Aggression — lasted eight years, devastated much of eastern China, and ended only with Japan's surrender in August 1945. It was fought by the Nationalist government, the Communists, and countless local resistance forces, and it cost China dearly in lives, cities and countryside alike.

From incident to total war

Japan had already seized Manchuria in 1931 and created the puppet state of Manchukuo. After the Marco Polo Bridge Incident of July 1937, Japanese forces advanced rapidly, taking Beijing, Tianjin and Shanghai after months of bitter fighting, and then the Nationalist capital, Nanjing, in December 1937. The Nationalist government retreated up the Yangtze to Chongqing, which became its wartime capital, while the Communists built base areas in the north, centred on Yan'an.

In 1937 the Nationalists and Communists formed a Second United Front against Japan. The alliance was fragile: the two sides cooperated against a common enemy while also competing for territory, recruits and political legitimacy, and clashes between them continued during the war. Local guerrilla forces, militias and ordinary villagers who sheltered soldiers, hid grain or passed information were essential to resistance, and they bore much of the retaliation when Japanese forces punished areas suspected of supporting guerrillas.

Nanjing and the problem of numbers

After capturing Nanjing in December 1937, Japanese troops killed large numbers of Chinese soldiers who had surrendered and of civilians, and committed widespread rape and looting over the following weeks. The episode is known as the Nanjing Massacre. How many died is contested: Chinese official and memorial accounts commonly cite 300,000 deaths, while some Western and Japanese scholars argue for lower figures, and the range in the scholarly literature is wide. The lesson does not settle that dispute; it records that the killing was large-scale, documented by contemporaries including foreign residents of Nanjing, and that its scale remains debated because records are incomplete and definitions of the victims and the period differ.

The same caution applies to the war's overall toll. Scholarly estimates of Chinese deaths in the war commonly fall in the range of roughly 14 to 20 million, including deaths from military action, famine, disease and displacement, but the true figure cannot be fixed precisely. What is not in doubt is the scale of destruction: major cities were bombed, the Yellow River was deliberately breached by Nationalist forces in 1938 in an attempt to slow the Japanese advance — flooding large areas of Henan and displacing millions — and millions of Chinese became refugees.

China in the wider war

After Japan attacked Pearl Harbor in December 1941, China's war merged with the wider Second World War. The United States supplied China by air over the Himalayas — the "Hump" route — after Japan cut the Burma Road, and American air units, including the volunteer group known as the Flying Tigers, operated in China. China also contributed troops to the Burma campaign. Yet China received far less Allied material than the European theatres, and its armies remained poorly equipped for much of the war.

Japan announced its surrender on 15 August 1945, and the formal surrender was signed on 2 September 1945. For China, victory did not bring peace: within a year the Nationalists and Communists were again in full civil war, a conflict covered in this course's earlier lesson on the Long March and Civil War.

Why it matters

The war reshaped Chinese politics: it weakened the Nationalist government, expanded Communist base areas, and left a legacy of grievance and commemoration that still shapes relations between China and Japan. Reading its history requires holding two things together — the certainty that the suffering was immense, and the honesty that many of its numbers are estimates, not exact counts.