Saharat Thai Doem สหรัฐไทยเดิม
Subdivision ofThailand
1943–1945
Flag Coat of arms
Anthem
Phleng Chat Thai
Capital	Kengtung
Historical era	World War II
• Japan hands over the territory toThailand	18 August 1943
• Thailand returns annexed territories to the United Kingdom	15 August 1945
Preceded by Succeeded by British Burma British Burma
Today part of	Myanmar

Saharat Thai Doem (Thai:สหรัฐไทยเดิม,lit. 'Unified Former Thai Territories') was an administrative division of Thailand. It encompassed parts of theShan States ofBritish Burma annexed by the Thai government after theJapanese conquest of Burma.

By means of thisannexation,Axis-aligned Thailand expanded northwards to the22nd parallel north and gained a border with China.Chiang Tung (Kengtung) was the administrative headquarters of the province.^[1] After the Phibun government fell in August 1944, the new Thai government communicated to the British that it renounced all claims to the Shan States and northern Malaya, and that it would immediately return the territories to Britain. The Churchill government did not accept the Thai overture, and was prepared to retaliate.^[2] The Thai army evacuated in August 1945.^[3]

The territory of the Northern Thai province was mountainous, except for a few small areas, such as theintermontane basin of Kengtung. TheSalween River marked the western border of the new province. The northernmost point was the frontier town ofPangsang.

There were few roads connecting the districts and most of the population lived in small mountain villages. The area was mostly inhabited byTai Yai people, but there were also sizable communities ofLahu,Akha andWa people, as well as those belonging to theKaren ethnic group, including theRed Karen and theKayan people.

Thai Prime MinisterPlaek Phibunsongkhram signed a secret agreement with theEmpire of Japan on 14 December 1941 and committed theThai armed forces to participate in the plannedMalayan Campaign andBurma Campaign. An alliance between Thailand and Japan was signed on 21 December 1941. On 25 January 1942, the Thai government, believing theAllies beaten, declared war on the United States and the United Kingdom. As a reward for entering into a military alliance with them, the Japanese agreed to return to ThailandKedah,Perlis,Kelantan, andTerengganu, the fourMalayan provinces ceded to the British in 1909, as well as parts of Shan State inBritish Burma that were deemed "lost territories" of Thailand.^[4][5]

In accordance with the Thai military alliance with Japan that was signed on 21 December 1941, the Japanese agreed that the area of eastern Shan State east of the Salween was to be under Thai administration.

In 1942, theImperial Japanese Army (IJA) accompanied by the ThaiPhayap Army invaded the Federated Shan States from Thailand. The defense of the Shan States had been left to the Nationalist Chinese forces, upon the request of the British. The 93rd Division of the Chinese Army defended Kengtung, while the 249th and 55th Divisions guarded from the Kengtung to Karenni States along the Thai border. The Japanese forces with superior air power went on to dislodge the Nationalist Chinese forces by November 1942.^[6] The IJA allowed the Phayap Army to occupy all ofKengtung State and the four trans-Salween districts ofMöng Tang,Möng Hang,Möng Kyawt andMöng Hta, ofMongpan State. Following the existing agreement between Thai Prime MinisterPlaek Phibunsongkhram (Phibun) and theEmpire of Japan, on 18 August 1943, the Japanese government agreed to the Thai annexation of Kengtung and part ofMongpan State (as well as the annexation of Kelantan, Trengganu, Kedah, Perlis states and nearby islands in Malaya.)^[7] The Thai government wanted the two districts ofMöngmaü andMehsakun ofMawkmai of the southern Shan states as well as part ofKantarawadi in the Karenni states, all east of the Salween River, but the Japanese assigned them to their clientState of Burma in September 1943.^[8]

Panglong, a Chinese Muslim town inBritish Burma, was entirely destroyed by the Japanese invaders in theJapanese invasion of Burma.^[9] TheHui Muslim Ma Guanggui became the leader of the Hui Panglong self defense guard created by Su who was sent by theKuomintang government of theRepublic of China to fight against the Japanese invasion of Panglong in 1942. The Japanese destroyed Panglong, burning it and driving out the over 200 Hui households out as refugees. Yunnan and Kokang received Hui refugees from Panglong driven out by the Japanese. One of Ma Guanggui's nephews was Ma Yeye, a son of Ma Guanghua and he narrated the history of Panglang included the Japanese attack.^[10] An account of the Japanese attack on the Hui in Panglong was written and published in 1998 by a Hui from Panglong called "Panglong Booklet".^[11] The Japanese attack in Burma caused the Hui Mu family to seek refuge in Panglong but they were driven out again to Yunnan from Panglong when the Japanese attacked Panglong.^[12]

The Thai army would remain there until the end of the war although the Thai government began to alter its position when the tide of war began to favor the allies. After the Phibun government fell in August 1944, the new government ofKhuang Aphaiwong communicated to the British government it renounced all claims to the Shan States and northern Malaya, and that it would immediately return the territories to Britain. The Churchill government did not accept the Thai overture, and was prepared to retaliate.^[2] The Thai army evacuated the two Shan States only in August 1945.^[3]

A rudimentary administration was set up early in the invasion with Kengtung as the centre. Made up mostly of small rural communities, during the occupation the Thai territory in Shan State remained a largely forgotten place. Wounded or ill Thai soldiers who were sent to Bangkok were shocked that there was no knowledge or concern about the hardships of the northern Thai Army in the newly annexed territory.^[13]

• Dec 1942–1945Phin Choonhavan (b. 1891 – d. 1973)

Saharat Thai Doem was divided into twelve districts(amphoe), to which later a further district was added. Mueang Phan was a special district.^[14]

• The Thai flag was hoisted in Kengtung on 5 June 1942. Kengtung (Chiang Tung) would become the capital city of the new Thai province.
• The Thai military reached as far as Mandalay, but the Japanese only sanctioned the annexation of part of the territories conquered. Thai tanks took part in the battles near Taunggyi.
• Thai and Japanese soldiers met in Mandalay (Burma Campaign 1942).

• Japanese invasion of Burma
• State of Burma
• Phayap Army
• Thailand in World War II

• Aung Tun, Sai (2009).History of the Shan State: From Its Origins to 1962. Chiang Mai: Silk Worm Books.ISBN 978-974-9511-43-5.

• WWII, Cold War and Thailand
• World War 2 campaigns in Burma (in Thai)
• The Land Boundaries of Indochina: Cambodia, Laos and Vietnam (archived)
• Annexed territories (in Thai)
• Manifesto for Greater East Asian Co-operation

19°15′N101°30′E / 19.250°N 101.500°E /19.250; 101.500

• States and territories established in 1943
• States and territories disestablished in 1945
• Former provinces of Thailand
• 1942 in Thailand
• 1942 in Burma
• Burma campaign
• Military history of Thailand during World War II
• Military history of Burma during World War II
• Japan–Thailand relations
• Kengtung State
• British Empire in World War II
• World War II sites in Burma
• World War II occupied territories

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