Southern Asia 1941: Japanese Intervention in French Indochina

Germany's defeat of France in 1940 left the French overseas empire vulnerable. Japan, which was already at war with China, decided to exploit this opportunity and invaded northern French Indochina. It was soon followed by Thailand, which retook territories French Indochina had annexed earlier in the century.


Changes to the map 7 August 1940–17 January 1941

French Indochina: The Japanese have occupied northern French Indochina. Thailand has seized upon this opportunity to invade and reclaim lost provinces.

British Somaliland: The Italians have taken Berbera, completing their conquest of the territory.

Sudan: The Italians are beginning their evacuation of Kassala.

Vichy French Empire: French India (Pondicherry) has declared for the Free French.

British Protectorates in the Persian Gulf

The British Residency of the Persian Gulf maintained British India's influence in a number of Gulf states from the 19th Century until 1947. These states were nominally independent - and shown as such in most atlases from the period - but all signed treaties guaranteeing British control over their foreign affairs.

The Sultanate of Muscat and Oman was the only one of these states with significant international relations, having obtained trade agreements with the US and France before it signed its treaty with Britain. Maps of the time often show Trucial Oman and even Qatar as regions of Oman.

Trucial Oman was the region to the west of Oman which collectively signed treaties with Britain. The sheikhdoms of this region were often called the Trucial States, and later became the United Arab Emirates. However at this time they had little unity, with no regional council until 1952.

Indian Empire

The British Indian Empire, also known as the British Raj, was comprised of a complex of presidencies, provinces, protectorates, and agencies. Only the top level subdivisions are shown here.

The area under direct British rule was known as British India and made up of presidencies and provinces - a presidency simply being the name for an older province.

Outside British India, but often included within the sphere of the presidencies/provinces, were the hundreds of protectorates or 'princely states'. These were indirectly ruled states, the largest being Hyderabad, Kashmir, and Mysore. The others were either collected into agencies - which might in turn contain other smaller agencies - or fell under the sway of the provinces.

Main Events

22–26 Sep 1940 Japanese invasion of French Indochina

The Empire of Japan and Vichy French Indochina sign an accord granting Japan the rights to station up to 6,000 troops in Indochina, and to move troops and supplies through Indochina. Within a few hours, columns from the IJA 5th Division cross the border at three places and close in on the railhead at Lang Son, near Longzhou, contravening the new agreement. French Indochinese colonial troops and Foreign Legionaires contest the invasion until 25 September. On the 26th, Japanese forces come ashore at Dong Tac and move on Haiphong, with fighting coming to an end that wikipedia

27 Sep 1940 Tripartite Pact

Joachim von Ribbentrop of Nazi Germany, Galeazzo Ciano of the Kingdom of Italy, and Saburō Kurusu of the Empire of Japan signed the Tripartite Pact in Berlin, capital of Germany. The 10 year Pact recognized the right of Germany and Italy to establish a new order in Europe while Japan did so in Greater East Asia; it also compelled the contracting Powers to come to the aid of any one of them should they be attacked by a Power not presently involved in either World War II in Europe or the Sino-Japanese War (implicitly making it a defensive pact against the United States and the Soviet Union).in wikipedia

18 Oct 1940 British reopening of Burma Road

Following the Japanese occupation of northern French Indochina and the continuation of Japanese offensives in China, the United Kingdom ended its conditional three month closure of the Burma Road, allowing supplies to reach Nationalist China wikipedia

5 Jan–9 May 1941 Franco-Thai War

Following a number of border skirmishes along the disputed Mekong frontier, war erupted between the Kingdom of Thailand and Vichy-controlled French Indochina. While the superior Royal Thai Air Force bombed cities in Laos and Cambodia, the Thai army overran French border defenses. The war was brought to an end by a Japanese mediated ceasefire, after which French Indochina was forced to cede most of the disputed territory to wikipedia