The Franco-Thai War (1940-1941)

The Franco-Thai War was fought between Thailand under General Plaek Pibunsonggram and Vichy French forces in the Indochinese peninsula.

This war preceded by a few months the outbreak of the Pacific War itself.

Negotiations with France before World War II had shown that the French government was willing to make minor changes to the borders between Thailand and French Indochina.

After the defeat of France in 1940, Major General Plaek Phibunsongkhram (Phibun), Prime Minister of Thailand, decided that the situation gave the Thais a much better chance of regaining the territories lost during the reign of King Chulalongkorn .

The context of the Franco-Thai war

General Phibun

On June 12, 1940, the Thai government agreed to sign a non-aggression pact with France.

But after the French defeat in 1940, Thai Prime Minister Phibun saw an opportunity for Thailand to recover the territories abandoned to France during Chulalongkorn's reign and to avenge the humiliations suffered in 1893 (the annexation of Laos to French Indochina) and 1904.

The provinces in question are those of Melou Prei and Tonlé Repou in 1904, and the provinces of Battambang, Sisophon and Siem Reap in 1907 which were ceded in 1867 in exchange for recognition of the protectorate over the Khmer kingdom; these provinces were all attached to Cambodia).

The weakening of the metropolis made maintaining French control over Indochina risky and difficult.

The colonial administration, deprived of aid and reinforcements, had been forced to allow the Japanese to settle in French Indochina after the capture of Lang Son (offensive of September 22-25, 1940).

The weak French resistance to this invasion convinced the Phibun regime that a military confrontation would turn to its advantage.

The forces present

The French forces in Indochina consisted of an army of approximately 60,000 men, 12,000 of whom were from mainland France (and served in the so-called "sovereignty" regiments), organized into 41 infantry battalions, two artillery regiments, and one engineer battalion.

The most obvious weakness of the French army was its lack of tanks: it could field only 20 Renault FT-17s compared to 134 for the Thai army.

Renault FT-17 tank

The Vichy air force in Indochina consisted of around a hundred aircraft, of which around sixty could be sent to the front line: 30 Potez 25s, four Farman 221s, six Potez 542s, nine Morane-Saulnier MS406s and eight Loire 130s.

The Thai army was relatively well equipped. It consisted of about sixty thousand men, divided into four armies, the largest being Burapha's army with five divisions.

Independent formations under the direct authority of the Army High Command included two motorized cavalry battalions, one artillery battalion, one signals battalion, one engineer battalion, and one armored regiment.

The artillery had at its disposal a mixture of old Krupps, modern Bofors howitzers and field mortars (guns?), while sixty Carden-Loyd tankettes and thirty Vickers 6-Ton made up the armoured corps.

The Thai air force and navy had benefited from the attention of the Thai government in the 1930s.

The Royal Thai Air Force had approximately 200 combat aircraft and 120 trainer aircraft.

The American embargo of October 1940 had pushed Bangkok to supply itself more from Japan: during the winter of 1940, the country received 33 Nakajima Ki-27s and 9 Mitsubishi Ki-21-I bombers, as well as around thirty Mitsubishi Ki-30s.

However, it instead used older models, notably Martin B-10s.

The navy, for its part, comprised around thirty units, including two Japanese-built armored coastguards, the Thonburi and the Sri Ayuthaya (armed with four 203 mm caliber guns), nine Italian-built torpedo boats (equipped with six 533 mm torpedo tubes) and four coastal submarines (delivered in 1938 by Japan).

It also included a small anti-submarine aviation force and two battalions of marine riflemen.

The triggering of operations

Following nationalist and anti-French demonstrations in Bangkok, border skirmishes followed one another along the Mekong.

The numerically superior Thai air force bombed Vientiane, Sisophon, and Battambang during the day with complete impunity.

The French air force attempted retaliatory raids, but the damage to Thailand was much less.

Admiral Jean Decoux, Governor General of Indochina, also acknowledged that Thai airmen flew like men with several campaigns under their belt. In December 1940, Thailand occupied Pak-Lay and Champassak Province.

In early January 1941, the Burapha Thai and Isaan armies launched an offensive on Laos and Cambodia.

French resistance was immediately in place, but many units were overwhelmed by the better-equipped Thai forces.

The Thais quickly occupied Laos, while in Cambodia the French resistance was more effective.

On January 16, France launched a large-scale counter-offensive led by the 5th Foreign Infantry Regiment against the Thai villages of Yang Dang Khum and Phum Préav, where the fiercest fighting of the war took place.

The French counterattack was blocked and ended in a retreat, but the Thais could not pursue the French forces, their tanks having been pinned to the ground by French anti-tank guns.

The Battle of Koh Chang

While the situation on land was critical for France, the Governor General of Indochina, Admiral Jean Decoux, gave authorization to Admiral Jules Terraux, commander of the French Navy in French Indochina, to carry out an operation against the Thai Navy.

The French fleet in Indochina was then heterogeneous. An "occasional group" was formed with the light cruiser La Motte-Picquet as flagship, the Bougainville-class colonial cruisers Dumont d'Urville and Amiral Charner, and the old cruisers Marne and Tahure.

This fleet was placed under the command of Captain Régis Bérenger, commanding the La Motte-Picquet.

The French force has several seaplanes: 2 Loire 130s, one of which was left in Saigon by the Suffren for the needs of the operation, 3 Potez 452s, 2 of which were embarked by the La Motte-Picquet, 3 Gourdou 832s, 2 of which were launched by the colonial avisos.

Although obsolete, these seaplanes would play a key role in the battle by precisely locating Thai ships at Koh Chang.

Five river gunboats accompanied the fleet, but did not participate in the battle.

The light cruiser La Motte-Picquet

The Thai fleet is composed of two armored coastguard ships Sri Ayuthia and Dhomburi, ten torpedo boats, including nine modern ones of Italian manufacture, one old one of British manufacture, two avisos, one submarine, and two minelayers.

The order is given to available French warships to attack in the Gulf of Thailand.

An aerial reconnaissance was carried out on January 16 at Satahib (eastern tip of Bangkok Bay) and at Koh Chang.

The French fleet left Poulo Condor Island on January 15. It crossed the Gulf of Siam and surprised a squadron of the Thai fleet at anchor at dawn on January 17.

Thai ships attempted to take advantage of the multitude of islets protecting the Koh Chang naval base, but French units blocked the exit channels and bombarded them from several sides.

At the end of the fight, which lasted just under two hours, the toll was heavy on the Thai side.

A third of its fleet was disabled. The torpedo boats Chonburi, Songhkla and Trad, built in Italy between 1935 and 1937, were sunk (the Trad was later refloated and returned to service).

The armored coastguard Dhomburi was seriously damaged and eventually capsized on the Chantaboum Bar. Her sister ship, the Sri Ayuthia, was torpedoed by the La Motte-Picquet.

Of the three torpedoes launched, only one hit, but forced the ship to run aground to avoid sinking.

These two armored units built in Japan in 1937 and 1938 were armed with twin 203 mm turrets.

The official death toll is 36 men (including the commander of the Thonburi) killed on the Thai side, but the figures are probably higher, probably 300 men died.

Several Japanese officers on board the Siamese ships were also said to have died in the clash.

The French fleet returned to Saigon virtually intact. It suffered no casualties, a few injuries, and only minor material damage.

Naval historian Jacques Mordal has noted that the Battle of Koh Chang is the only naval battle fought and won during both World Wars by a French naval force, on exclusively French plans and with exclusively French means.

In his War Memoirs, General de Gaulle recalls "the brilliant naval victory of January 17, 1941, during which the cruiser La Motte-Picquet and some French avisos sank the Siamese fleet."

Following this victory, Captain Régis Bérenger was promoted to Rear Admiral.

This feat of arms, however, remains little known in France, perhaps because it was won by the Vichy navy.

However, the name of this battle can be found on a few streets and squares and on a few memorials in Brittany and Vendée.

Conclusion and consequences of the Franco-Thai war

The death toll from the war varies according to different sources. Some mention around 3,400 deaths.

Japan, eager to secure Thailand's military collaboration, quickly intervened as a mediator in the conflict.

An ultimatum first imposed an armistice on the two belligerents, proclaimed on January 28. On May 9, France, under Japanese pressure, signed a peace treaty, by which it abandoned the provinces of Battambang and Siem Reap, taken from Cambodia, and Champassak and Sayaburi (taken from Laos, which thus ceded the territories on the right bank of the Mekong), a territory of more than 50,000 km2 inhabited by 420,000 people.

This treaty was followed by another between France and Laos on August 21.

This annexation led, in July 1941, to the imposition by the United States of an embargo on oil deliveries to Japan and the creation, with the help of the Anglo-Saxon secret services, of the Thai Seri (the Free Thais), a clandestine anti-Japanese organization.

The Thai government verbally promised the Japanese that it would allow them passage through its territory during the planned attack on Malaysia by the Empire.

On December 8, 1941, Thailand still not having responded to Japanese demands, Japan decided to ignore them and, in order to be able to pass into Malaysia, invaded the territory of Thailand.

This invasion ended with the Battle of Prachuab Khirikhan and a ceasefire a few hours later, then Thailand allied itself with Japan.

The territories annexed by Thailand were not returned to France until November 1947, but France did not retain them for long, as the territories of Indochina gained independence shortly afterwards.

The weakness that France has revealed is one of the factors of this decolonization.

The losses

The French army suffered a total of 321 casualties, 15 of whom were officers. After January 28, it had 178 missing (6 officers, 14 non-commissioned officers, and 158 enlisted men).

The Thais captured 222 men (17 North Africans, 80 French, and 125 Indochinese).

The Thai army suffered a total of 54 killed and 307 wounded. 41 Thai sailors and navy personnel were killed, and 67 wounded.

At the Battle of Ko Chang, 36 men were killed, including 20 crew members from HTMS Thonburi, 14 from HTMS Songkhla, and 2 from HTMS Chonburi.

The Thai Air Force lost 13 men. 21 Thai soldiers were captured by the French.

About 30% of French aircraft had been rendered unusable by the end of the war, some due to minor, unrepaired damage sustained during air raids.

The Vichy Air Force admitted the loss of one Farman F221 and two Morane-Saulnier MS.406 destroyed on the ground, but in reality its losses were greater.

During its first combat experience, the Royal Thai Air Force claimed to have shot down five French aircraft in the air and seventeen destroyed on the ground, for the loss of three of its own aircraft in the sky and five to ten destroyed in French air raids on Thai airfields.

Video on the Franco-Thai War

Contemporary news about the war:

Source: wikipedia.org/