Japan's 1933 Withdrawal from the League of Nations Over Manchuria

In response to the League of Nations' adoption of the Lytton Report (February 1933), which concluded that Japan's seizure of Manchuria was illegal and demanded Japanese withdrawal, the Japanese delegation—led by Yōsuke Matsuoka—walked out of the League Assembly on February 24, 1933. Japan formally withdrew from the League of Nations on March 27, 1933, effective two years later per Article 1 of the Covenant.

Context

• Sept 1931: Kwantung Army stages Mukden Incident; occupies Manchuria.
• 1932: Japan establishes puppet state Manchukuo under former Qing emperor Puyi.
• Dec 1931: League appoints Lytton Commission to investigate.
• Oct 1932: Lytton Report issued: Manchukuo not product of genuine self-determination; Japan should withdraw.
• Feb 1933: League Assembly votes 42–1 (only Japan dissenting) to adopt report.

Significance

• First major power to quit the League; fatally undermined collective security.
• Emboldened Italy (Abyssinia, 1935) and Germany (rearmament, Rhineland 1936).
• Japan pursued unilateral expansionism, leading to full-scale war in China (1937) and WWII in Asia.

Japan's exit signaled the collapse of the post-WWI international order and the triumph of militarist expansionism in Tokyo.