I've read the obvious wiki article (which is rather small), but did not really find an answer. At the end of the article, it says:

To prepare for an invasion of the Dutch East Indies, some 140,000 Japanese troops invaded southern Indochina on 28 July 1941. Japanese forces remained in Indochina until the end of World War II.

Those are literally the last 2 sentences of the article. It also mentioned negotiations with Vichy France, which might lead me to believe that the region was simply transferred to Japanese control without any fighting. That's rather unbelievable IMO, and the article neither says that explicitly nor makes a single inline citation of a source.

How did Japan conquer this region? Obviously I'm interested in what Japan did successfully that France, America, and China apparently did not do in the Vietnam War (Parts 1, 2, and 3).

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    What made you think "Japan successfully conquer[ed] Vietnam" in the first place? Vichy France conceded de facto military control in the '41 Protocol Concerning Joint Defense and Joint Military Cooperation. I'm not sure why you find this "rather unbelievable". And this is obviously completely different to the later Vietnam Wars.
    – Semaphore
    May 3, 2016 at 19:53
  • The native Vietnamese didn't really like the French and only really obeyed them while France could credibly show force. Once France fell, the garrison lost control over parts of Vietnam not actually occupied. Japan also cultivated the anti French forces like Ho Chi Minh. May 3, 2016 at 20:40
  • @Semaphore What made you think "Japan successfully conquer[ed] Vietnam" in the first place? The fact that they occupied it 1941 - 1945. I'm not sure why you find this "rather unbelievable". It's not Vichy's transfer that's unbelievable. It's the supposedly little to no fighting, either by French or by the Vietnamese. (PS, 140k occupying troops seems overkill if there really was no fighting). And this is obviously completely different to the later Vietnam Wars. That's exactly why I'm asking this question. Why is the Japanese occupation so completely different from the Vietnam War?
    – DrZ214
    May 4, 2016 at 0:31
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    @DrZ214 Those 140k troops were for invading Malaysia and Indonesia. Japan didn't "occupy" Vietnam with them so much as they used Vietnam as a military springboard.
    – Semaphore
    May 4, 2016 at 5:35

3 Answers 3


Japan did not conquer Vietnam, it had already been conquered by the French. For most of the war Japan left the existing French colonial government in place and negotiated the rights to station troops there and move them through the country.

Initially, Japan was only interested in Northern Indochina to cut off supplies to China. To this end they signed an accord with Vichy France in Sept 1940 to be able to station and move a limited number of troops through French Indochina (modern Laos, Cambodia, and Vietnam). The Japanese immediately violated this but eventually things settled down. Japan did not advance further south for fear of antagonizing the US and Britain.

In October 1940 Thailand took the opportunity of France's weakness to win back territory lost in the Franco-Siamese War of 1893. After defeats for the French, the Japanese stepped in to mediate a cease-fire in January 1941. France ceded disputed border provinces to Thailand.

Realizing they could no longer defend their overseas territories, and not being at war with Japan, in July 1941 Vichy France signed the "Protocol Concerning Joint Defense and Joint Military Cooperation". This secured Indochina for the Vichy French and gave the Japanese airfields and bases close to attack South East Asia.

This state of affairs of mostly peaceful cooperation between the French colonial government and Japanese military continued until almost the end of the war. In March 1945, with France restored and the war turning against them, the Japanese launched a coup d'état in Indochina. They redeployed their troops to surround the French garrisons and suddenly ordered them to disarm. Fighting was brief, and in a single day the Japanese dismantled French rule in Indochina.

The Japanese split Indochina into three puppet states under sympathetic rulers: the Empire of Vietnam, the Kingdom of Kampuchea (Cambodia), and the Kingdom of Laos and made them all part of the Greater East Asia Co-Prosperity Sphere.

By handing Vietnam independence from French colonial rule, and eventually allowing reunification of north and south Vietnam, Japan avoided a fight with the native populations. Once the Empire of Japan fell, the short lived Empire of Vietnam did as well and the Viet-Minh took over in the August Revolution.

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    Thank you for the well-sourced answer, but I was hoping for something more from the perspective of the Vietnamese (not just the colonial govt.). In all my reading so far, I never come across any mention of a battle between Japanese forces and actual Vietnamese. This leads me to suspect that the Vietnamese never fought the Japanese invaders. If true, I'm wondering why. Since posting this question, I have since suspected that perhaps the Vietnamese saw the Japanese as liberators (as was the initial case of the Baltic States), but that is only a guess of mine, not a source.
    – DrZ214
    May 6, 2016 at 1:47
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    @DrZ214 There was guerilla fighting against both the French and Japanese. The Viet Minh even acted as defacto govt in places. Very generally, what was different during WWII is 1) the Viet Minh were brand new in 1941 and not effective until 1945, 2) no major power was supporting them (there was no Cold War), 3) without TV reporters the French and Japanese could be as brutal as they wanted, and 4) there was no independent North Vietnam to use as a base. I'd have to do research to say more. This deserves its own, more direct, question. Ask it, please.
    – Schwern
    May 6, 2016 at 2:21
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    My grandpa being in the resistance that the Viet Minh eventually took over (another subject) recounted that they avoided fighting the Japanese and the Japanese also avoided them. No major battles ever took place. Some in VN Quốc Dân Đảng did see Japan as potential ally, but the Việt Minh did not. I remember grandpa said the Japanese were "strangely" brutal and they would either blow themselves up by putting a grenade in their hat or commit hara kiri rather than be captured. Feb 7, 2017 at 18:57

The Japanese conquered Singapore a much more visible, if smaller target with some 35,000 men (far fewer than the defenders). They also conquered the Philippines with a force of about 130,000 men, against mixed American-Filipino forces.

That was because of two reasons. 1) the Japanese troops were better at jungle fighting than the French, British and Americans. 2) With a war going on in Europe neither Vichy France (the occupied by Nazi Germany with a 90,000 man size limitation on her army), nor Britain could spare meaningful forces for the Far East. America was also unprepared for war. In that context, the 140,000 man army that the Japanese committed to Vietnam was enormous. Chinese proverb: "When no tiger is on the mountain, the jackal is king."

The Vietnamese were not armed or trained for fighting until after World War II. The war did a lot to "educate" them in this regard. Put another way, Japan was "in the right place at the right time." In the words of U.S. Civil War cavalry general Nathan Bedford Forrest, they "got there firstest with the mostest."


Japan was only occupying small areas that had economic importance, not trying to control the whole country.

Also, in world wars soldiers do not guff around. If civilians misbehave, they will just go in and machine gun everybody. When the U.S. was in Viet Nam, we put all sorts of political restrictions on the soldiers, such as not allowing them to shoot civilians. The Japanese were under no such restrictions and in all the areas they occupied they brutally slaughtered anyone involved in resisting them. For example, after the Doolittle Raid, the Japanese completely wiped out the Chinese villages that had sheltered the American pilots. They murdered everyone, some 20,000 people or more, man woman and child, and burned down every single building in an 80-mile radius. They even killed all the livestock; every single cow, goat, chicken, dog, whatever. With policies like that, the civilian resistance to the Japanese occupation was pretty limited.

  • I don't understand why this is downvoted so much; the first sentence pretty much sums up the situation imho.
    – Semaphore
    May 4, 2016 at 5:36
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    It's more about the second paragraph, at least for me.
    – DevSolar
    May 4, 2016 at 9:43
  • 1
    People are downvoting the answer not because it is incorrect, but because it spoils their fantasy world where soldiers do not shoot civilians. May 4, 2016 at 19:56
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    I haven't downvoted, but the claims about what the Japanese did in retribution to the Chinese sheltering those who did Doolittle could do with a citation.
    – Golden Cuy
    May 5, 2016 at 9:09
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    @AndrewGrimm Even if true, it would have to be shown that was a primary reason for Japanese success in Vietnam.
    – Schwern
    May 6, 2016 at 2:25

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