Japanese invasion of Manchuria

On September 18, 1931, Japan’s Kwantung Army invaded China’s Manchuria region, acting immediately after the Mukden incident—a false flag attack staged by Japanese soldiers to justify the invasion. By February 1932, Japan had set up the puppet state of Manchukuo. The occupation lasted until mid-August 1945, near the end of World War II, when Soviet and Mongolian forces overwhelmed the Japanese during the Manchurian Strategic Offensive Operation.

The invasion drew global attention. The League of Nations sent the Lytton Commission, led by British politician Victor Bulwer-Lytton, to assess the situation. In October 1932, the commission concluded that Manchukuo should not be recognized and that Manchuria must return to Chinese control. In response, Japan withdrew from the League.

**Background**

Japan had held the Liaodong Peninsula as a leased territory since the Russo-Japanese War ended in 1905, giving it informal rule over Manchuria. By the late 1920s, 39.4% of all Japanese colonial investments were in the region. In the early 1930s, Japan faced two major problems: its economy had been struggling for three years due to the global financial crisis, and in Manchuria, nationalists under Zhang Xueliang—once a Japanese ally—had stirred strong anti-Japanese feeling. In 1928, Zhang rejoined Chiang Kai-shek’s Kuomintang, forming the Nationalist government, which steadily eroded Japan’s influence. Radical groups within the government and army plotted to act on the “Manchurian question.” The Hamaguchi government, especially Foreign Minister Kijūrō Shidehara’s non-interventionist China policy, was seen as harmful to Japan’s future interests. To end Shidehara’s conciliatory approach, radical officers like Daisaku Komoto and Suzuki Teiichi planned a coup to take over the civilian government in Tokyo.

**Prelude**

Two key events led to the invasion. In July 1931, near Changchun in the Wanpaoshan region, a dispute over Korean farmers building an irrigation system on Chinese-owned land turned violent. No one was killed or seriously hurt, but Japanese extremists used the incident to stoke anti-Chinese sentiment and push for a more aggressive policy in Manchuria. Believing full control of Manchuria served Japan’s interests, and acting in the spirit of *gekokujō* (the low overturns the high), Kwantung Army Colonel Seishirō Itagaki and Lieutenant Colonel Kanji Ishiwara devised a plan to provoke an invasion by staging a false flag incident. Meanwhile, central army authorities played up the Manchurian issue to win public support and create a sense of urgency, hoping to prevent disarmament. Rumors of an expedition spread in August and early September, and the government was repeatedly asked whether war in Manchuria was coming. The operation was originally set for August 28 but was moved up. On the night of September 18, a bomb—likely placed by Captain Imada Shintaro of the Army Special Service Agency—was detonated near the South Manchuria Railway tracks at Mukden. The bomb was far enough away to cause no real damage. Fighting broke out between Japanese railway guards and Chinese soldiers from a nearby barracks. After fifteen hours of fierce combat, the Japanese had seized all key military sites in and around Mukden.

**Initial Annexation**

On September 18, the Japanese Imperial General Headquarters decided to localize the incident and informed the Kwantung Army command. But General Shigeru Honjō, the Kwantung Army’s commander-in-chief, ordered his forces to expand operations along the entire South Manchuria Railway. Early on September 19, the 29th Infantry Regiment entered Mukden, overwhelmed Chinese defenders, and captured the inner walled city. The 2nd Battalion took Pei Ta Ying after stubborn resistance, then moved on to Tung Ta Ying. The 2nd Division drove remaining Chinese troops from eastern Mukden. The 1st Battalion engaged Chinese forces at Kuan Cheng Tze, near Changchun. That same day, General Senjūrō Hayashi of the Chōsen Army in Korea—responding to Honjō’s request—ordered the 20th Infantry Division to split, forming the 39th Mixed Brigade, which left for Manchuria without imperial authorization. By the end of September 19, Japan occupied Yingkou, Liaoyang, Shenyang, Fushun, Dandong, Siping, and Changchun. The next day, Chinese 2nd Army commander Wan Shu Cheng ordered the 44th and 643rd Regiments to withdraw from Taching to Tianjin. On September 21, Japan captured Jilin City; on September 23, it took Jiaohe and Dunhua. On September 26, Kirin’s governor, Zhang Zuoxiang, was deposed, and a “Provisional Provincial Government of Kirin” was declared, with Xi Qia as acting chairman. This new government was friendly to Japan.