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Historical ConflictFrench Indochina

Japanese coup d'état in French Indochina

Japan's March 1945 coup ended French colonial authority in Indochina overnight, installing puppet states that altered the region's postwar trajectory.

Duration & Scope

1945 ongoing

< 1 year

Key Facts

Date of operation
9 March 1945
Operation codename
Meigō Sakusen (Operation Bright Moon)
Puppet states created
3 (Empire of Vietnam, Kingdom of Kampuchea, Kingdom of Luang Prabang)
French garrisons overrun
All garrisons across the colony
French survivors' refuge
Nationalist China (harshly interned)

Strategic Narrative Overview

On 9 March 1945, Japanese forces simultaneously attacked French garrisons across Indochina. Despite French intelligence having anticipated some form of Japanese aggression, the speed and coordination of the assault caught defenders off guard. All French garrisons were overrun within hours. Surviving French troops and officials who could not be captured attempted to flee northward into Nationalist China, where they were interned under difficult conditions.

01 / The Origins

By early 1945, Japan was losing World War II and feared that French colonial forces in Indochina—nominally cooperative under the Vichy administration—would side with Allied forces in the event of an invasion. To preempt a French uprising that could destabilize their strategic position in Southeast Asia, Japanese commanders planned a swift, coordinated strike to eliminate French military and administrative power throughout the colony.

03 / The Outcome

With French authority dismantled, Japan installed three client states: the Empire of Vietnam under Emperor Bảo Đại, the Kingdom of Kampuchea, and the Kingdom of Luang Prabang. These nominally independent governments acquiesced to Japanese military presence. The coup effectively ended nearly a century of French colonial administration, creating a power vacuum that contributed directly to the postwar independence movements and subsequent conflicts in the region.

Belligerents & Mobilization Analysis

Side A

1 belligerent

Empire of Japan

Side B

1 belligerent

French Indochina (Vichy French colonial forces)
Outcome
Complete Japanese victory; French colonial authority eliminated; three Japanese-backed puppet states established across Indochina.

Location

Map of French IndochinaMap of French IndochinaFrench Indochina