Japan's 1931 invasion of Manchuria established a puppet state, triggered Japan's withdrawal from the League of Nations, and presaged wider conflict in Asia.
Key Facts
- Invasion start date
- 18 September 1931
- Pretext used
- Mukden Incident, a staged false flag operation
- Puppet state established
- Manchukuo, February 1932
- Occupation ended
- Mid-August 1945, following Soviet offensive
- League of Nations response
- Lytton Commission report issued October 1932
- Japanese reaction to League findings
- Japan withdrew entirely from the League of Nations
By the Numbers
Location
Cause → Event → Consequence
Japanese military personnel in the Kwantung Army staged the Mukden Incident on 18 September 1931, a deliberate false flag operation in which they sabotaged a section of railway and blamed Chinese forces, fabricating a pretext for military action against the Manchuria region of China.
Following the Mukden Incident, the Kwantung Army launched a full invasion of Manchuria. By February 1932, Japanese forces had secured the region and established the puppet state of Manchukuo, with the occupation continuing until mid-August 1945 when Soviet and Mongolian forces launched the Manchurian Strategic Offensive Operation.
The invasion drew international scrutiny, prompting the League of Nations to dispatch the Lytton Commission, whose October 1932 report recommended against recognizing Manchukuo and called for the return of Manchuria to Chinese sovereignty. Japan rejected these findings and withdrew from the League of Nations entirely, undermining collective security mechanisms ahead of wider global conflict.
Belligerents & Mobilization Analysis
Side A
2 belligerents
Side B
2 belligerents