Mukden Incident (1931): How Japan Seized Manchuria

The Mukden Incident was a staged explosion on the Japanese-owned South Manchuria Railway near Mukden (now Shenyang) on the night of 18 September 1931. Officers of Japan’s Kwantung Army set off the charge, blamed Chinese troops and used it as a pretext to conquer all of Manchuria within months. The incident led to the puppet state of Manchukuo, exposed the weakness of the League of Nations and is often seen as the opening act of the war in Asia that merged into the Second World War.

Background: Japan in Manchuria

Manchuria, China’s vast north-eastern region, was rich in coal, iron, timber and farmland. After victory in the Russo-Japanese War of 1904–1905, Japan took over Russia’s lease on the Liaodong Peninsula and the southern branch of the Chinese Eastern Railway, which became the South Manchuria Railway. Japan was allowed to station troops along the line to guard it. These forces became the Kwantung Army.

By the late 1920s Japan had large investments in the region, and many in the army saw Manchuria as vital for raw materials, for settlement and as a buffer against the Soviet Union. At the same time, Chinese nationalism was rising. Manchuria was ruled by the warlord Zhang Xueliang, who in 1928 had pledged loyalty to Chiang Kai-shek’s Nationalist government after Kwantung Army officers assassinated his father, Zhang Zuolin, by blowing up his train.

The Great Depression hit Japan hard after 1929, deepening support for expansion. Many army officers distrusted the civilian government of Prime Minister Wakatsuki Reijiro and Foreign Minister Shidehara Kijuro, whose policy towards China was relatively cautious.

The plot

The plan was drawn up by staff officers of the Kwantung Army, above all Colonel Seishiro Itagaki and Lieutenant Colonel Kanji Ishiwara. Ishiwara believed Japan must seize Manchuria to prepare for a future great war. They acted without authorisation from the government in Tokyo, though some officers in the army’s central command knew of the scheme in outline.

At about 10.20 pm on 18 September 1931, a small charge of explosives was detonated beside the railway track at Liutiaohu, a few kilometres north of Mukden and close to the Beidaying barracks of Zhang Xueliang’s army. The operation was led by Lieutenant Suemori Kawamoto. The damage was so slight that a train passed over the spot shortly afterwards without trouble.

The invasion of Manchuria

The Kwantung Army immediately claimed that Chinese soldiers had attacked the railway. Japanese troops stormed the Beidaying barracks that night, and by the morning of 19 September they held Mukden. Zhang Xueliang, who was in Beijing, ordered his forces largely not to resist, hoping to avoid a full war and to rely on international pressure.

On 21 September the Japanese army in Korea, under General Senjuro Hayashi, crossed into Manchuria without imperial sanction, reinforcing the Kwantung Army. The government in Tokyo, unable to control its own army, accepted the fait accompli and approved funding for the operations after the event. Japanese aircraft bombed Jinzhou in October 1931. Qiqihar fell in November after resistance by the Chinese general Ma Zhanshan, Jinzhou in January 1932 and Harbin in February 1932.

Manchukuo

On 1 March 1932 Japan proclaimed the state of Manchukuo (“State of the Manchus”). Its nominal head was Puyi, the last emperor of the Qing dynasty, who had been deposed as a child in 1912. He became Chief Executive and, from 1934, Emperor of Manchukuo.

In reality, power lay with the Kwantung Army and Japanese officials who held key posts in every ministry. Japan formally recognised Manchukuo in September 1932. Only a handful of states, mostly Japan’s later allies, ever did so. Manchukuo became a base for heavy industry and Japanese settlement, and its rule was marked by forced labour and harsh repression of resistance.

Effects inside Japan and China

In Japan, newspapers and much of the public cheered the army’s victories, and the incident strengthened militarist and ultranationalist groups. The Wakatsuki cabinet fell in December 1931. On 15 May 1932 young naval officers assassinated Prime Minister Inukai Tsuyoshi, ending the era of party-led cabinets. Civilian leaders who opposed the army increasingly risked their careers or their lives.

In China, the loss of Manchuria provoked boycotts of Japanese goods and anger at Chiang Kai-shek’s government, which preferred to fight the Communists first and avoid open war with Japan. Fighting also spread to Shanghai in January 1932, where Chinese troops resisted a Japanese attack for several weeks before a ceasefire in May. Zhang Xueliang was widely blamed for abandoning his homeland, a reputation that later helped drive him to detain Chiang at Xi’an in 1936.

The League of Nations and the Lytton Report

China appealed to the League of Nations. In December 1931 the League created a commission of enquiry under the British politician Lord Lytton, which visited Japan, China and Manchuria in 1932. The United States, not a League member, issued the Stimson Doctrine in January 1932, refusing to recognise territorial changes made by force.

The Lytton Report, published on 2 October 1932, found that the Japanese military operations of 18 September could not be regarded as legitimate self-defence and that Manchukuo was not the result of a genuine independence movement. It proposed autonomy for Manchuria under Chinese sovereignty.

On 24 February 1933 the League Assembly adopted the report by 42 votes to 1, with only Japan against and Siam abstaining. The Japanese delegation, led by Yosuke Matsuoka, walked out, and on 27 March 1933 Japan announced its withdrawal from the League. By then Japanese forces had also invaded the neighbouring province of Rehe (Jehol), and the Tanggu Truce of May 1933 left Japan in control of Manchuria and created a demilitarised zone south of the Great Wall.

Key people

• Seishiro Itagaki and Kanji Ishiwara, Kwantung Army staff officers who planned the incident.
• Shigeru Honjo, commander of the Kwantung Army, who approved the expansion of operations.
• Zhang Xueliang, ruler of Manchuria, who withdrew rather than fight.
• Puyi, last Qing emperor, installed as the figurehead of Manchukuo.
• Lord Lytton (Victor Bulwer-Lytton), chair of the League commission of enquiry.

Timeline

• 1928, 4 June: Zhang Zuolin is killed when Kwantung Army officers blow up his train.
• 1931, 18 September: The railway explosion at Liutiaohu near Mukden.
• 1931, 19 September: Japanese troops occupy Mukden.
• 1931, 21 September: Japanese forces from Korea cross into Manchuria.
• 1932, 1 March: Manchukuo is proclaimed with Puyi as Chief Executive.
• 1932, 2 October: The Lytton Report is published.
• 1933, 24 February: The League Assembly adopts the report; Japan’s delegation walks out.
• 1933, 27 March: Japan announces its withdrawal from the League of Nations.

Legacy

The incident showed that Japan’s army could make foreign policy on its own, a pattern that weakened civilian government in the 1930s. The League’s failure to stop Japan encouraged other aggressors, including Italy in Ethiopia in 1935. In 1937 fighting near Beijing escalated into full-scale war between Japan and China, which brought atrocities such as the Nanjing Massacre.

Japan’s responsibility for the explosion was confirmed after 1945, including by testimony at the Tokyo war crimes trial, and is accepted by historians in Japan and elsewhere. Manchukuo collapsed when the Soviet Union invaded in August 1945. In China, 18 September is a day of national remembrance, and the September 18 Historical Museum stands near the site in Shenyang.

Why it matters

The Mukden Incident was a deliberate false-flag operation that opened fourteen years of Japanese occupation in north-east China. It revealed the limits of collective security under the League of Nations and set East Asia on the path to wider war.