Prelude to Invasion: Japan’s Imperial Ambitions in Manchuria

The stage for the September 18 Incident was set decades earlier through Japan’s gradual encroachment into Northeast China. Following victory in the Russo-Japanese War (1904-1905), Japan gained control of Russia’s leasehold on the Liaodong Peninsula and the South Manchuria Railway. This gave Japan a strategic foothold in the resource-rich region they called Manchuria.

By the 1920s, the Japanese Kwantung Army had established itself as a powerful force in the region, operating with increasing autonomy from Tokyo. Army officers like Kanji Ishiwara and Seishirō Itagaki developed radical expansionist theories, viewing Manchuria as essential for Japan’s survival – both as a source of raw materials and as a buffer against Soviet expansion.

The 1929 Wall Street Crash and subsequent global depression intensified Japan’s economic motivations. As Western markets collapsed, Japanese militarists argued that formal control of Manchuria would provide economic security. Meanwhile, Chinese nationalism was rising under Chiang Kai-shek, threatening Japan’s privileged position in Manchuria.

The Mukden Incident: A Manufactured Casus Belli

On September 18, 1931, Lieutenant Suemori Kawamoto of the Independent Garrison Unit carried out a covert operation that would change Asian history. At around 10:20 pm near Liutiao Lake (Willow Palisade), his team planted explosives on a section of the South Manchuria Railway track. The minor explosion caused negligible damage – trains continued running that night – but provided the pretext Japan needed.

Kwantung Army officers immediately blamed Chinese saboteurs and launched coordinated attacks. By midnight, Japanese forces assaulted the Beidaying Barracks near Shenyang (then called Mukden), home to 7,000 Chinese troops. Despite outnumbering the 500 Japanese attackers, the Chinese garrison obeyed Nanjing’s controversial “non-resistance” policy, suffering heavy casualties as they withdrew.

Within hours, Japanese units fanned out across Shenyang, capturing key installations including the arsenal (with 150,000 rifles) and airport (260 planes). By noon on September 19, the entire city was under Japanese control. Simultaneously, Japanese forces attacked cities along the South Manchuria Railway, occupying Antung, Yingkou, and Changchun within 48 hours.

The Rapid Conquest of Northeast China

The Japanese advance proceeded with stunning speed, facilitated by Chiang Kai-shek’s decision to prioritize fighting Communists over resisting Japan. By September 21, Japanese forces from Korea (led by General Senjūrō Hayashi) crossed the Yalu River to reinforce the Kwantung Army, violating international law.

Key milestones in the occupation included:
– September 21: Jilin City captured after provincial commander Xi Qia surrendered
– November 19: Qiqihar falls despite heroic defense by General Ma Zhanshan
– January 3, 1932: Jinzhou captured, completing southern Manchuria’s conquest
– February 5, 1932: Harbin occupied after fierce street fighting

In just five months, Japan gained control over 500,000 square miles of territory – an area larger than Germany and France combined – with minimal combat losses. The rapid collapse shocked international observers and exposed the weakness of both Chinese resistance and the League of Nations.

Crafting a Puppet State: The Birth of Manchukuo

Even before completing military conquest, Japan began constructing a puppet regime. On February 16, 1932, prominent collaborators including Zhang Jinghui and Xi Qia attended the “Founding Conference” in Shenyang. They established the “Northeast Administrative Committee” which declared independence from China on February 18.

The last Qing emperor, Puyi, became the centerpiece of Japanese plans. Lured from Tianjin by promises of restoration, he was installed as Chief Executive on March 1, 1932. The new state adopted a five-color flag and named Changchun as its capital, renamed Xinjing (“New Capital”).

Critical documents cemented Japanese control:
– The March 10, 1932 secret agreement granted Japan control over Manchukuo’s military, transportation, and official appointments
– The Japan-Manchukuo Protocol (September 15, 1932) legalized Japanese military occupation
– In 1934, Manchukuo became the “Manchu Empire” with Puyi as emperor

International Response and Consequences

The League of Nations’ Lytton Commission condemned Japanese aggression in 1932, leading to Japan’s dramatic withdrawal from the League in 1933. This marked the first major failure of collective security and emboldened fascist powers worldwide.

Manchukuo became:
– An industrial base for Japan’s war machine (producing 40% of Japan’s aluminum by 1941)
– A testing ground for chemical weapons used against Chinese civilians
– The model for later Japanese puppet regimes in China

The occupation’s brutality – including Unit 731’s biological warfare experiments and use of forced labor – created lasting trauma. Resistance persisted through anti-Japanese guerilla groups, some Communist-led, foreshadowing the broader Second Sino-Japanese War (1937-1945).

Historical Legacy and Modern Memory

The Mukden Incident’s consequences reverberate today. It:
– Marked the opening act of World War II in Asia
– Demonstrated the weakness of international institutions against aggression
– Cemented the Kwantung Army’s influence in Japanese politics
– Created lasting regional tensions between China, Japan, and Korea

Annual commemorations in China (known as “9.18”) maintain public awareness. The Shenyang 9.18 History Museum, built near the Liutiao Lake explosion site, presents the incident as the beginning of China’s “14-year Resistance War” against Japan. Meanwhile, historical memory remains contested in Japan, where textbooks often minimize the invasion’s scale and atrocities.

The Mukden Incident stands as a pivotal moment when imperial aggression, enabled by international inaction and Chinese disunity, reshaped Asia’s geopolitical landscape with consequences that endure nearly a century later.