View source for Franco-Thai War

{{Short description|1940–41 conflict in French Indochina}}
{{Infobox military conflict
| conflict          = Franco-Thai War
| partof            = the aftermath of the [[Japanese invasion of French Indochina]], the [[South-East Asian theatre of World War II]] and the [[Pacific War|Pacific Theater]] of [[World War II]]
| image             = Indochine française (1913).jpg
| image_size        = 200px
| caption           = Map of the French Indochina prior to [[World War I]]
| date              = October 1940 – January 28, 1941{{efn|Fighting ended with a ceasefire on January 28 and the war formally ended with a peace treaty on May 9|group=efn}}
| place             = [[French Indochina]], [[Laos]], [[Cambodia]]
| casus             = 
| territory         = On Japanese decision, disputed territories in French Indochina ceded by France to Thailand<ref name=Fall>{{cite book|last1=Fall|first1=Bernard B.|title=Street Without Joy: The French Debacle in Indochina|date=1994|publisher=Stackpole Books|isbn=0-8117-1700-3}}</ref>{{RP|22}}<ref name=Windrow>{{cite book|last1=Windrow|first1=Martin|title=The Last Valley|date=2004|publisher=Weidenfeld and Nicolson|isbn=0-306-81386-6}}</ref>{{RP|78}}
| result            = Indecisive<ref>Tucker, World War II: The Definitive Encyclopedia and Document Collection p. 649</ref>
* Japanese-mediated armistice<ref>Fall, p. 22. "On the seas, one old French cruiser sank one-third of the whole Thai fleet ... Japan, seeing that the war was turning against its pupil and ally, imposed its 'mediation' between the two parties."</ref>
| combatant1        = {{flag|Vichy France|name=Vichy France}}
* {{nowrap|{{flag|French Indochina}}}}
| combatant2        = {{flagicon image|Flag of Thailand (non-standard colours).svg}} [[History of Thailand (1932–1973)|Thailand]]
'''Supported by:'''<br>{{flag|Japan}}
| commander1        = {{flagicon image|Flag of France.svg}} [[Jean Decoux]]
| commander2        = {{flagicon image|Flag of Thailand (non-standard colours).svg}} [[Plaek Phibunsongkhram]]
| strength1         = 50,000 men<br>(38,000 colonials)<br>20 light tanks<br>100 aircraft<br>1 light cruiser<br>4 avisos
| strength2         = 60,000 men<br>134 tanks<br>140 aircraft<ref name="Royal Thai Air Force 1976"/><br>3 coastal defense ships<br>12 torpedo boats<br>4 submarines
| casualties1       = '''Land''':<br>321 killed or wounded<br>178 missing<br>222 captured<br>22 aircraft destroyed<br>'''Sea''':<br>None<ref name="G & H">{{cite book |title=Face à la France, une victoire de Thaïs |last=Journoud |first=Pierre |publisher=[[:fr:Guerres & Histoire]] |edition=8 |date=2012 |pages=72}}</ref><ref name= NET>"The Battle of Koh Chang (January 1941)" netmarine.net</ref><br>'''Total''': 721+ casualties
| casualties2       = '''Land''':<br>54 killed<ref name="Sorasanya Phaengspha 2002">Sorasanya Phaengspha (2002) The Indochina War: Thailand Fights France. Sarakadee Press.</ref><br>307 wounded<br>21 captured<br>8–13 aircraft destroyed<br>'''Sea''':<br>36 killed<ref name = "G & H"/><ref name= NET>"The Battle of Koh Chang (January 1941)" netmarine.net</ref><br>3 torpedo boats sunk<ref name = "G & H"/><br>1 coastal defense ship grounded<br>'''Total''':<br>418<ref name = "G & H"/><ref name= NET>"The Battle of Koh Chang (January 1941)" netmarine.net</ref> casualties
| notes             = {{notelist}}
| campaignbox       = {{Franco-Thai War}}
{{Campaignbox French Indochina}}
{{Campaignbox Vichy France Military in World War II}}
{{Campaignbox South-East Asian Theatre}}
{{Campaignbox Pacific War}}
{{Japanese colonial campaigns}}
{{Campaignbox World War II}}
{{Campaignbox Indochina Wars}}
}}

The '''Franco-Thai War''' (October 1940 – January 28, 1941, {{langx|th|กรณีพิพาทอินโดจีน|Karani Phiphat Indochin}}; {{langx|fr|Guerre franco-thaïlandaise}}) was fought between [[History of Thailand (1932–1973)|Thailand]] and [[Vichy France]] over certain areas of [[French Indochina]].

Negotiations shortly before [[World War II]] had shown that the French government was willing to alter the boundaries between Thailand and French Indochina, but only slightly. Following the [[Fall of France]] in 1940, Major-General [[Plaek Pibulsonggram]] (popularly known as "Phibun"), the prime minister of Thailand, decided that France's defeat strengthened the Thais' negotiating position to regain the vassal state [[Territorial losses of Thailand|territories that were ceded]] to France during King [[Chulalongkorn]]'s reign.

The German and Italian military occupation of [[Metropolitan France]] rendered France's hold on French Indochina and its other overseas territories tenuous. The colonial administration was cut off from outside help and supplies. After the [[invasion of French Indochina]] in September 1940, Japan forced the French to allow them to set up military bases. The French's seemingly subservient behavior lulled the Phibun regime into believing that France would not seriously resist a military confrontation by Thailand.

==Opposing forces==
===French===
The French military forces in Indochina consisted of an army of approximately 50,000 men, 12,000 of whom were French, organized into forty-one [[infantry]] [[battalion]]s, two [[artillery]] [[regiments]], and a battalion of [[Combat engineer|engineers]].<ref>{{cite web | last = Stone| first = Bill| url = http://www.sonic.net/%7Ebstone/history/vichyvssiam.shtml| title = Vichy Indo-China vs Siam, 1940-41 }}</ref> The [[Vichy French Army]] had a shortage of [[Armoured warfare|armor]], and it could field only 20 [[Renault FT]] [[tank]]s against the nearly one hundred [[Royal Thai Army]] armored vehicles. The bulk of the French forces stationed near the Thai border
consisted of the Indochinese infantry of the 3rd and 4th Regiments of [[Tonkinese Rifles]] (''Tirailleurs Tonkinois''), together with a battalion of [[Degar|Montagnards]] (indigenous [[Vietnam]]ese highlanders), French regulars of the Colonial Infantry (''[[Troupes coloniales]]''), and [[French Foreign Legion]] units.<ref>Rives, Maurice. ''Les Linh Tap''. {{ISBN|2-7025-0436-1}} page 90</ref>

The [[Vichy French Navy]] had the [[French cruiser Lamotte-Picquet|light cruiser ''Lamotte-Picquet'']] and four [[aviso]]s in French Indochina.

The [[Vichy French Air Force]] (''Armée de l'Air'') had approximately 100 aircraft, of which roughly 60 could be considered front-line. These included thirty [[Potez 25|Potez 25 TOE]] [[Reconnaissance aircraft|reconnaissance]]/[[fighter-bomber]]s, four [[Farman F.220|Farman 221]] heavy [[bomber]]s, six [[Potez 540|Potez 542]] bombers, nine [[Morane-Saulnier M.S.406]] [[Fighter aircraft|fighters]], and eight [[Loire 130]] reconnaissance/bomber [[flying boat]]s.<ref name=Ehrengardt>{{cite book|last1=Ehrengardt|first1=Christian J|last2=Shores|first2=Christopher |title=L'Aviation de Vichy au combat: Tome 1: Les campagnes oubliées, 3 juillet 1940 - 27 novembre 1942|date=1985|publisher=Charles-Lavauzelle}}</ref>

===Thai===

The slightly larger Thai Army was a relatively well-equipped force.<ref name=Hesse>{{cite book|last1=Hesse d'Alzon|first1=Claude|title=La Présence militaire française en Indochine|date=1985|publisher=Publications du service historique de l'Armée de Terre|location=Vincennes}}</ref> Consisting of 60,000 men, it was made up of four [[Field army|armies]]. The largest were the Burapha Army with five [[Division (military)|divisions]] and the Isan Army with three divisions. Independent formations under direct control of the army high command included two motorized [[cavalry]] battalions, one artillery battalion, one [[Military communications|signals]] battalion, one engineer battalion, and one armored regiment. The artillery was a mixture of [[Krupp gun]]s and modern [[Bofors 40 mm Automatic Gun L/60|Bofors gun]]s and [[howitzer]]s, while 60 [[Carden Loyd tankette]]s and 30 [[Vickers 6-ton]] tanks made up the bulk of the army's tank force.

The [[Royal Thai Navy]] included two [[Thonburi-class coastal defence ship|''Thonburi''-class]] [[coastal defense ship]]s, 12 [[torpedo boat]]s, and four Japanese-made [[submarines]].<ref name="Young, Edward M. 1995">Young, Edward M. (1995) ''Aerial Nationalism: A History of Aviation in Thailand''. Smithsonian Institution Press.</ref> The Royal Thai Navy was inferior to the French naval forces in [[Southeast Asia]], but the [[Royal Thai Air Force]] held both a quantitative and qualitative edge over the local ''Armée de l'Air'' units.<ref name="Young, Edward M. 1995" /> Among the 140 aircraft that composed the [[Royal Thai Air Force]]'s first-line strength were 24 [[Mitsubishi Ki-30]] light bombers, nine [[Mitsubishi Ki-21]] heavy bombers, 25 [[Curtiss P-36 Hawk|Curtiss Hawk 75N]] fighter planes, six [[Martin B-10]] medium bombers, and 70 [[Vought O2U Corsair]] [[Observation aircraft|observation]]/[[attack aircraft]].<ref name="Royal Thai Air Force 1976">Royal Thai Air Force. (1976) ''The History of the Air Force in the Conflict with French Indochina''. Bangkok.</ref>

==Campaign==
While nationalist demonstrations and anti-French rallies were being held in [[Bangkok]], several border skirmishes erupted along the [[Mekong]] frontier. The superior Royal Thai Air Force then conducted daytime bombing runs over military targets in [[Vientiane]], [[Phnom Penh]], [[Sisophon]], and [[Battambang]] with impunity. The French retaliated with their own air attacks, but the damage they caused was less than equal. The activities of the Thai air force, particularly in the field of dive-bombing,<ref name="Young, Edward M. 1995"/> was such that Admiral [[Jean Decoux]], the governor of French Indochina, grudgingly remarked that the Thai planes seemed to have been flown by men with plenty of war experience.<ref>Elphick, Peter. (1995) ''Singapore: the Pregnable Fortress: A Study in Deception, Discord and Desertion''. Coronet Books.</ref>

[[File:Renault FT17 IMG 8414.jpg|thumb|left|French troops used a handful of World War I-era [[Renault FT]] tanks during the conflict.]]

On 5 January 1941, following the report of a French attack on the Thai border town of [[Aranyaprathet]], the Thai Burapha and Isan Armies launched an offensive on [[French Protectorate of Laos|Laos]] and [[French Protectorate of Cambodia|Cambodia]]. French response was instantaneous, but many units were simply swept aside by the better-equipped Thai forces. The Thai army swiftly overran [[Laos]], but the French forces in [[Cambodia]] managed to rally and offer more resistance.<ref>[http://www.ww2f.com/topic/12620-vichy-versus-asia-the-franco-siamese-war-of-1941/ Vichy versus Asia: The Franco-Siamese War of 1941]</ref>

[[File:Battle of Koh Chang 17 january 1941 (English version).svg|thumb|The naval [[Battle of Ko Chang]], January 17, 1941]]

At dawn on January 16, 1941, the French launched a large counterattack on the Thai-held villages of Yang Dang Khum and Phum Preav, initiating the fiercest battle of the war. Due to poor coordination and nonexistent intelligence against the entrenched and well-prepared Thai forces, the French operation was stopped and fighting ended with a French retreat from the area. However, the Thais were unable to pursue the retreating French, as their forward tanks were kept in check by the gunnery of [[French Foreign Legion]] artillery.

With the situation on land rapidly deteriorating for the French, Admiral Decoux ordered all available French naval forces into action in the [[Gulf of Thailand]]. In the early morning of 17 January, a French naval squadron caught a Thai naval detachment by surprise at anchor off [[Ko Chang]] island. The subsequent [[Battle of Ko Chang]] was a tactical victory for the French and resulted in the sinking of two Thai torpedo boats and the disabling of a coastal defense ship, with the French suffering no casualties.<ref name= NET>"The Battle of Koh Chang (January 1941)" netmarine.net</ref> Fearing the war would turn in France's favor, the Japanese intervened, proposing an armistice be signed.

On 24 January, the final air battle took place when Thai bombers raided the French airfield at [[Angkor]], near [[Siem Reap]]. The last Thai mission bombing Phnom Penh commenced at 07:10 on 28 January, when the Martins of the 50th Bomber Squadron set out on a raid on Sisophon, escorted by thirteen [[Curtiss P-36 Hawk|Hawk 75Ns]] of the 60th Fighter Squadron.<ref name="Royal Thai Air Force 1976"/><ref name=Ehrengardt />

==Armistice==
[[File:Provinces of Cambodia loss to Thailand during Franco-Thai War.png|thumb|The provinces ceded from Cambodia by France to Thailand were regrouped into new Thai provinces: [[Phra Tabong province|Phra Tabong]], [[Phibunsongkhram Province|Phibunsongram]], and [[Nakhon Champassak Province|Nakhon Champassak]]]]

Japan subsequently stepped in to mediate the conflict. A general ceasefire had been arranged to go into effect at 10:00 on 28 January, and a Japanese-sponsored "Conference for the Cessation of Hostilities" was held at Saigon, with preliminary documents for an armistice between the governments of Marshal [[Philippe Pétain]]'s French State and the Kingdom of Thailand signed aboard the cruiser [[Japanese cruiser Natori|''Natori'']] on 31 January 1941. On 9 May, a peace treaty was signed in [[Tokyo]],<ref name=Hesse /><ref name="Young, Edward M. 1995"/> with the French being coerced by the Japanese to relinquish their hold on the disputed border territories. France ceded the following provinces to Thailand from [[French protectorate of Cambodia|Cambodia]] and [[French protectorate of Laos|Laos]]:

* [[Battambang Province|Battambang]] and [[Pailin]], which were reorganized as [[Phra Tabong Province]]
* [[Siem Reap Province|Siem Reap]], [[Banteay Meanchey Province|Banteay Meanchey]] and [[Oddar Meanchey Province|Oddar Meanchey]], which were reorganized as [[Phibunsongkhram Province]]
* [[Preah Vihear Province|Preah Vihear]], which was merged with a part of [[Champassak Province]] of [[French Laos|Laos]] opposite [[Pakse]] to form [[Nakhon Champassak Province]]
* [[Sainyabuli Province|Xaignabouli]], including part of [[Luang Prabang]] Province, which was renamed [[Lan Chang Province]]

==Treaty==
The resolution of the conflict was widely acclaimed by the people of Thailand, and was seen as a personal triumph for Phibun. For the first time in its history, Thailand had been able to extract concessions from a European power, albeit a weakened one. For the French in [[French Indochina]], the conflict was a bitter reminder of their isolation after the [[Fall of France]]. They felt that an ambitious neighbor had taken advantage of a distant colony being cut off from a weakened parent. Without hope of reinforcements, the French had little chance of offering a sustained resistance.

To commemorate the victory, Phibun erected the [[Victory Monument (Bangkok)|Victory Monument]] in Bangkok. Thailand invited Japan and Germany to join in the celebration of its construction.

The Japanese wanted to maintain both their working relationship with [[Vichy France|Vichy]] and the status quo; therefore, the Thais were forced to accept only a quarter of the territory that they gained from the French, in addition to having to pay six million [[French Indochinese piastre|piastres]] as a concession to the French.

However, the real beneficiaries of the conflict were the Japanese, who were able to expand their influence in both Thailand and Indochina. The Japanese wanted to use Thailand and Indochina as their military bases to invade [[British rule in Burma|British Burma]] and [[British Malaya]] later. The Japanese won from Phibun a secret oral promise to support them in an attack on Malaya and Burma.
Phibun did not keep his word.<ref>Charivat Santaputra (1985) Thai Foreign Policy 1932–1946. Thammasat University Press.</ref>

Relations between Japan and Thailand were subsequently stressed, as a disappointed Phibun switched to courting the British and Americans to ward off what he saw as an imminent Japanese invasion.<ref name="Stowe-1991">Judith A. Stowe. (1991) ''Siam becomes Thailand: A Story of Intrigue''. University of Hawaii Press. {{ISBN|0-8248-1393-6}}</ref> However, on 8 December 1941, the Japanese [[Japanese invasion of Thailand|invaded Thailand]] at the same time as the [[Japanese invasion of Malaya]]. Pearl Harbor was attacked one-and-a-half hours after Malaya and Thailand were. Fighting between Japanese and Thai forces lasted only five hours before a ceasefire was agreed. Thailand would be [[Thailand in World War II|allied with Japan]] until 1945.

After the war, in October 1946, northwestern Cambodia and the two Lao enclaves on the Thai side of the [[Mekong River]] were returned to French sovereignty when the [[Provisional Government of the French Republic|French provisional government]] threatened to veto Thailand's membership in the [[United Nations]].<ref>Terwiel, B.J. (2005) ''Thailand's Political History: From the Fall of Ayutthaya to Recent Times''. River Books.</ref> This led to the conclusion of the [[Franco-Siamese Settlement Treaty of 1946]] that settled the issue and paved the way to restoration of diplomatic relations between the two countries.

==Casualties==
The French army suffered a total of 321 casualties, of whom 15 were officers. The total number of missing after 28 January was 178 (six officers, 14 non-commissioned officers and 158 enlisted men).<ref name=Hesse /> The Thais had captured 222 men (17 North Africans, 80 Frenchmen, and 125 Indochinese).<ref name="Royal Thai Air Force 1976"/>

The Thai army suffered 54 men killed in action and 307 wounded.<ref name="Sorasanya Phaengspha 2002"/> 41 sailors and marines of the Thai navy were killed, and 67 wounded. At the [[Battle of Ko Chang]], 36 men were killed, of whom 20 belonged to [[HTMS Thonburi|HTMS ''Thonburi'']], 14 to HTMS ''Songkhla'', and two to [[HTMS Thonburi|HTMS ''Chonburi''.]] The Thai air force lost 13 men. The number of Thai military personnel captured by the French was just 21.

About 30 percent of the French aircraft were rendered unserviceable by the end of the war, some as a result of minor damage sustained in air raids that remained unrepaired.<ref name="Young, Edward M. 1995"/> The Armée de l'Air admitted the loss of one Farman F221 and two Morane M.S.406s destroyed on the ground, but its losses were really greater.<ref name=Ehrengardt />

In its first experience of combat, the Royal Thai Air Force claimed to have shot down five French aircraft and destroyed 17 on the ground, against the loss of three of its own in the air and another five to 10 destroyed in French air raids on Thai airfields (

==See also==
* [[Thailand in World War II]]
* [[Japanese occupation of Cambodia]]
* [[Japanese coup d'état in French Indochina|Japanese ''coup d'état'' in French Indochina]]
* [[HTMS Sri Ayudhya|HTMS ''Sri Ayudhya'']]

==References==
{{reflist|2}}

==Bibliography==
*{{cite magazine|last=Young|first=Edward M.|title=France's Forgotten Air War|magazine=[[Air Enthusiast]]|date=1984|issue=25 |pages=22–33 |issn=0143-5450}}

==Further reading==
* Paloczi-Horvath, George.  "Thailand's War with Vichy France." ''History Today'' (1995) 45#3 pp 32–39.
* Wong, Ka F. ''Visions of a Nation: Public Monuments in Twentieth-Century Thailand'', White Lotus, Bangkok 2006

==External links==
* [http://france1940.free.fr/e41index.html#Indochina "France 1940...something"]
* {{webarchive |url=https://web.archive.org/web/20091027105105/http://geocities.com/thailandwwii/ftw.html |date=October 27, 2009 |title="The French-Thai War" }}
* [https://web.archive.org/web/20090327141619/http://www.ww2f.com/cbi-theater/22091-vichy-versus-asia-franco-siamese-war-1941-a.html The 1941 franco-siamese war in the World War II context]
* {{in lang|fr}} [http://www.netmarine.net/bat/croiseur/lamotte/kohchang/ ''La bataille de Koh Chang''], netmarine.net

{{World War II}}
{{French Indochina}}
{{French colonial campaigns}}
{{History of Thailand 1932 - 1973}}
{{Occupation of France}}
{{Vichy France}}
{{authority control}}

{{DEFAULTSORT:Indochina}}
[[Category:Conflicts in 1940]]
[[Category:Conflicts in 1941]]
[[Category:Wars involving France]]
[[Category:Wars involving Thailand]]
[[Category:Military history of Thailand during World War II]]
[[Category:Military battles of Vichy France]]
[[Category:1940 in France]]
[[Category:1941 in France]]
[[Category:1940 in Thailand]]
[[Category:1941 in Thailand]]
[[Category:Wars involving Vietnam]]
[[Category:France–Thailand military relations]]
[[Category:20th-century military history of Thailand|Franco-Thai War]]