The Treaty of Tokyo ends the Franco-Thai War

On the morning of 9 May 1941 in Tokyo, representatives of France, acting on behalf of French Indochina, and of Thailand signed a peace convention ending the Franco-Thai War. An executive protocol was attached to the convention, and alongside it two protocols involving Japan were signed: a Japanese-French one and a tripartite one in which the Japanese government guaranteed that the settlement would be carried out. The Japanese information bureau announced it that same day, and the United States ambassador in Tokyo, Joseph Grew, immediately cabled the news to Washington.

Some accounts speak of a peace treaty “negotiated through Japanese mediation”. The documents of both sides show, however, that it is hard to speak of mediation in the ordinary sense. The fighting had stopped on 28 January, and from March the peace terms were a foregone conclusion. Japan drew the borders and imposed them on both parties, above all on France. The May treaty merely gave legal form to a settlement reached two months earlier.

From the Natori to Tokyo

The war broke out in the autumn of 1940, when the Thailand of Prime Minister Plaek Phibunsongkhram, known as Phibun, decided to exploit France’s defeat and recover the lands in Laos and Cambodia that Siam had ceded in 1893–1907. After border fighting and air raids, in January 1941 the Thai army occupied the Laotian territory on the right bank of the Mekong, but in western Cambodia it got bogged down. On 17 January a French squadron routed the Thai fleet off Ko Chang. Japan, which since September 1940 had had troops in Tonkin, wanted neither a Thai defeat nor a prolonged war. On 21 January it again offered its good offices. Phibun accepted at once; the government of Marshal Philippe Pétain did so a day later, without illusions: a refusal might give the Japanese army a pretext to seize the colony by force, and France could count on no help from the United States or Britain. A ceasefire came into force at 10 a.m. on 28 January, and on 31 January an armistice was signed aboard the Japanese cruiser Natori in the roads off Saigon.

Japan was no impartial arbiter. As early as the end of November 1940 the authorities in Tokyo had decided to support the award to Thailand of the Laotian territory on the right bank of the Mekong, and Phibun, as historians have established, had secretly offered the Japanese in September 1940 the right of passage through Thailand in the event of a war between Japan and the British in Malaya. The Japanese army and navy were after more than a border on the Mekong: mediation was to open the way to binding Indochina and Thailand to Japan militarily, politically and economically, including access to bases in the southern part of the peninsula.

A conference under dictation

The negotiations took place in Tokyo from 7 February to 11 March 1941 (some Japanese sources date the opening of the conference to 2 February). The host was the Foreign Minister, Yōsuke Matsuoka. The French delegation was led by René Robin, a former Governor-General of Indochina, assisted by the ambassador in Tokyo, Charles Arsène-Henry; the Thai delegation by Prince Wan Waithayakon, adviser to the Prime Minister and Bangkok’s ablest diplomat. The Thais began with maximum demands, at one point extending to the whole of Laos and Cambodia. The French wanted to limit their losses to what Thailand had actually occupied, that is, Laos on the right bank of the Mekong and two small bridgeheads in Cambodia.

The French ambassador later told Grew what this “mediation” had looked like. In mid-February Robin agreed with the Japanese Foreign Ministry on a direct meeting between the two delegations. Before it could take place, the French were suddenly summoned to the minister’s residence and handed a ready-made Japanese “plan”, drawn up, as they believed, at the dictation of the military. According to the French historian Éric Gojosso, who studied the archives of the French Foreign Ministry, the division of territory that later went into the treaty had been settled by Matsuoka alone on 13 February, without even consulting his own officials. On 24 February the Japanese presented their final proposal, and Vichy rejected it. Two milder variants then appeared, one from Matsuoka and the other worked out by Robin with the Japanese diplomat Jun Matsumiya, but both were shelved. The Japanese went back to the original plan, adding only the demilitarisation of the ceded territory, and presented it, as Grew put it, in the form of a “categorical ultimatum”. The government in Vichy, whose foreign affairs had been in the hands of Admiral François Darlan since February, gave way.

On 11 March an exchange of notes was initialled. The Japanese note began with the words: “We submit the following terms for unconditional acceptance.” The French reply stated that, although neither the situation on the spot nor the fortunes of war required it, the French government “in the present circumstances yields to the insistence” of Japan. This wording, inserted deliberately, allowed France to argue after the war that the settlement had been extorted. The head of the Thai delegation is said to have called the settlement “devoid of all common sense”, because it gave the Thais less than they had demanded. Even so, when the news reached Bangkok, sirens wailed and temple bells rang across the country. The next day Matsuoka set off on a journey to Berlin, Rome and Moscow, from which he brought back the neutrality pact with the Soviet Union. Over the next two months the details were worked out in Tokyo, until the treaty was signed on 9 May.

The peace terms

The convention restored to Thailand the lands lost under the agreement of 1904: the Laotian territory on the right bank of the Mekong, that is, the part of the kingdom of Luang Prabang lying opposite its capital, Luang Prabang (today’s Xaignabouli Province), and the western part of Champasak opposite Pakxé. Of the lands ceded in 1907, Cambodia lost the whole province of Bătdâmbâng (Battambang), the protectorate’s most fertile rice bowl, as well as most of Siĕm Réab (Siem Reap) and slivers of the provinces of Kâmpóng Thum and Stœ̆ng Trêng. The town of Siem Reap itself and the ruins of Angkor, the foremost symbol of the Khmers, remained with France. On the river the border was to follow the navigable channel, but the island of Khong stayed French. The border on Lake Tonlé Sap was drawn conventionally, and fishing and navigation on the lake were to be free to both sides.

The territory transferred to Thailand was to be demilitarised. French citizens, including the inhabitants of the colony, were to be treated there on an equal footing with Thais (except in acquiring real estate), and those living in the ceded areas could keep French citizenship within three years by moving to French territory. Thailand undertook to protect the tombs of the royal dynasty of Luang Prabang on the right bank of the Mekong and to pay France 6 million Indochinese piastres over six years. Disputes over the interpretation of the treaty were to be settled diplomatically and, failing that, submitted to the Japanese government for mediation. The border on the ground was to be demarcated by a commission under Japanese chairmanship.

The scale of the concessions is judged in different ways. Some studies, especially in English, say that the Thais had to settle for a small part of what they wanted. Gojosso, drawing on the French archives, states that France gave up nearly 70,000 square kilometres inhabited by almost half a million people, three times as much as Thailand had won on the battlefield (higher estimates of the area are also found in French literature). The two assessments can be reconciled: Thailand received far less than its maximum demands, but far more than its army had won.

The guarantee and its price

The real significance of the conference, however, lay, as Grew wrote in his March report, in the letters exchanged by Matsuoka with the heads of the two delegations. Japan guaranteed that the settlement would be carried out. France on behalf of Indochina, and Thailand on its own behalf, undertook not to conclude with third countries any agreements that would set them against Japan or harm its interests. Both sides also promised to develop “closer economic relations” with Japan. The American ambassador judged that Japan had thereby laid the foundations for political, economic and probably military control over Indochina and Thailand. His French colleague considered that for the colony this was a heavy blow but not a mortal one, whereas a sovereign state that accepted such a commitment was reduced to the role of Manchukuo.

Both sides paid a price. Three days before the peace was signed, on 6 May 1941, France and Japan concluded in Tokyo trade agreements and a convention on residence and navigation in Indochina. The colony granted Japan most-favoured-nation treatment, opened to the Japanese professions and mining and agricultural concessions hitherto closed to them, and undertook to deliver 700,000 tons of rice and 15,000 tons of rubber in 1941. The Governor-General, Admiral Jean Decoux, saved the French administration, but Indochina was increasingly working for the Japanese war economy. Thailand, for its part, paid for Japanese support with dependence. According to some historians Phibun gave the Japanese a verbal assurance that he would let their troops through in the event of a war between Japan and Britain. The border commission itself, which held its first meeting in Saigon on 21 August 1941, served, according to the account of a Japanese staff officer of the 25th Army, as cover for secret aerial reconnaissance of the Thai–Burmese borderland, for which the army had until then had no maps.

Winners and losers

In Bangkok the peace was celebrated as a great national victory: for the first time Thailand had taken land back from a European power, rather than having to give land up to one. Four provinces were created from the new territory: Phra Tabong (Battambang), Phibunsongkhram, named in honour of the Prime Minister, Nakhon Champassak and Lan Chang. On 24 June 1941, the anniversary of the 1932 revolution, the foundation stone was laid for the Victory Monument in Bangkok, dedicated also to those who fell in this war, and in July Phibun promoted himself to field marshal. At the same time fear of Japan was growing in Bangkok. Phibun, who owed his gains to Japan, began to seek arms and support in London and Washington, and assured the British minister that Thailand would defend itself against any aggressor, as Greece and Yugoslavia had done. The American minister in Bangkok did not believe it, writing that the country was “already in the Japanese trap”.

For the French in Indochina the treaty was a humiliation: a colony that had not been beaten on land and had won at sea was handing over the territory Tokyo had marked out. Battambang with its rice was regarded as the most painful loss. Cambodia lost its most fertile province and part of the old lands of Angkor, and King Sisowath Monivong died in April 1941 – embittered, according to some accounts, by the loss of territory. Decoux chose as his successor the eighteen-year-old Norodom Sihanouk, who was considered easier to manage than the other candidates. To compensate the Laotian king Sisavang Vong for the lost lands, France enlarged the kingdom of Luang Prabang by further provinces on the left bank of the Mekong in an agreement of 21 August 1941. Fear of further claims from Bangkok and of Japanese “Asia for the Asians” propaganda strengthened Decoux in his policy of courting local elites and fostering the separate identities of Khmers, Laotians and Vietnamese – a policy that turned against France after the war.

Place in the war

In Tokyo, for the first time in this war, Japan divided up the colonial possessions of a European state and acted as the arbiter of South-East Asia. The treaty strengthened its position in both Indochina and Thailand, and the commitments exchanged with Matsuoka limited both countries’ freedom of action towards Britain and the United States. In Washington and London it was read as a sign of a further advance southwards, and so it proved. In July 1941, under an agreement forced on Vichy, Japanese troops entered southern Indochina, occupying airfields and ports from which a few months later they could strike at Malaya. The United States, Britain and the Netherlands responded by freezing Japanese assets and imposing an oil embargo, which pushed Tokyo towards the decision for war.

On 8 December 1941 the Japanese landed in Thailand, which after a few hours of fighting agreed to let them pass through to Malaya and Burma, and soon concluded an alliance with Japan. Thailand kept the lands won in 1941 until the end of the war. France never recognised their loss, arguing that it had yielded under duress. In 1946, when Paris threatened to block Thailand’s admission to the United Nations, Bangkok, in an agreement signed in Washington on 17 November 1946, annulled the Treaty of Tokyo and returned all the ceded lands to Laos and Cambodia. The border reverted to its pre-war line, and the Victory Monument in Bangkok remains as a reminder of that short war and the Japanese peace.