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BATTLE // September 18, 1931

Japanese invasion of Manchuria

Source · Wikipedia

Significance

The Kwantung Army's invasion of Manchuria, triggered by the staged Mukden incident in September 1931, marked a decisive expansion of Japanese military power onto the Asian continent. The campaign concluded in February 1932 with Japan establishing Manchukuo, a puppet state that gave Tokyo control over a resource-rich region and a strategic staging ground for further operations into China proper. The occupation endured until mid-August 1945, when Soviet and Mongolian forces dismantled it during the Manchurian Strategic Offensive Operation. The invasion is significant as an early indicator of the Kwantung Army's willingness to act independently of civilian government and to manufacture pretexts for territorial seizure, dynamics that shaped the broader escalation toward full-scale war with China in 1937 and Japan's wider continental ambitions throughout the Second Sino-Japanese War.

Forces & casualties

Troop strength

  • Japan30,000–60,450
    medium
  • China160,000
    medium

China fielded a 3.5 : 1 numerical advantage

Casualties

  • Japan10,000
    medium22% loss rate
  • China50,000
    medium31% loss rate

Commanders (9)

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Last verified June 2026
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