The Japanese invasion of Thailand, 8 December 1941

[Pattaya One]

It is erroneously believed the war in the Pacific commenced with the Japanese surprise attack on the United States naval and air force base at Pearl Harbour in the Hawaiian Islands on Sunday 7 December 1941.

The reality is the attack on Pearl Harbour was in fact preceded by two events which took place in the early hours of Monday morning 8 December.

The date discrepancy is due to the International Date Line: Monday 8 December being the same time as Sunday 7 December in the eastern Pacific and the United States.

Japanese troops landing at Songkhla (courtesy Asianphile)

According to the London Gazette, possibly the first offensive action of the war in the Pacific took place on 7 December when the Japanese invasion fleet, led by Admiral Kondo, shot down a British Catalina flying-boat in the Gulf of Thailand.

What is not in any doubt is the first major offensive action was a landing by Japanese troops at Kota Baru on the north-east coast of British Malaya at 12:25 a.m. (local time) while the second act was the invasion of southern Thailand at 1:05 a.m. on Monday 8 December, despite the existence of a mutual friendship pact between the two countries. It wasn’t until 20 minutes later Japanese planes began bombing the United States Pacific Fleet in Pearl Harbour.

The Japanese military allocated a mere 138,000 men under General’s Yamashita and Lida, as well as two air divisions, to the conquest of Thailand, Burma, Malaya, and Singapore. The invasion forces were gathered together on Hainan Island in the South China Sea.

The slow-moving troop transports left Hainan under destroyer escort and headed south on 4 December. Admiral Kondo’s main force of two battleships and six heavy cruisers followed soon after.

By 6 December, the British in Malaya were aware a large Japanese amphibious force was heading towards the Gulf of Thailand. Bad weather prevented early detection and it wasn’t until the late evening of 7 December the Japanese forces were sighted anchoring off Kota Baru.

As early as July 1941, the British War Cabinet in London were painfully aware the Japanese occupation of northern Indo-China in September 1940 meant Malaya and Singapore were vulnerable to air attack.

With war almost inevitable the British military command in Malaya, commanded by Air Chief Marshal Sir Robert Brooke-Popham, drew up a contingency plan calling for a pre-emptive strike across the border into neutral Thailand to thwart any Japanese passage through that country. Codenamed Operation Matador the aim was to advance as far as the Kra isthmus and hope to deny the Japanese the use of the Pattani and Songkhla airfields.

In the months leading up to December, the strategic port of Songkhla and a few of the surrounding towns were a hive of foreign activity, filled with both Japanese and British spies. The Japanese posed as merchants, cameras slung over their shoulders as they photographed anything and everything. The British posed as simple tourists, some claiming to be journalists, others lawyers and accountants. It is suggested a couple pretended to be comedians and one, a circus acrobat. While the Japanese took their task seriously, the British ‘tourists’, most of whom were officers in various Malay-based regiments, treated the excursions as not much more than a lark. Given the relatively small size of the cities and towns and the few hotel facilities, it is no surprise that on a more than a few occasions both Japanese and British spies stayed at the same place.

Politically, Pibulsongkram, the Thai Prime Minister, faced a dilemma. With war between Japan and Britain almost certain and Thailand unlikely to be permitted to remain neutral due to its geographic position, Pibulsongkram knew he could not expect military support from either Britain or the United States.

After Japan moved troops into southern Indo-China in July 1941, he declared Thai neutrality. It was, as he well knew, an empty gesture, made more in hope than geopolitical reality. He said the Thai military would resist all incursions by foreign powers and publicly threatened to implement a scorched earth policy to deter invaders.

This was a public reversal of a private statement he made to the Japanese Naval Attaché in Bangkok in late September 1940 that he would not oppose Japanese landings in southern Thailand in return for an agreement on neutrality and a promise to help restore territory lost by the Thais to the French and British in the previous half-century.

Although the Japanese believed they had an agreement- albeit secret- to transit through Thailand unopposed, they nevertheless prepared for a resisted invasion.

Pibulsongkram knew the Japanese were too strong for Thailand to hold out for long, and protracted resistance would lead to his removal from power. He was not certain Japan would be victorious against the British and Americans and was therefore reluctant to commit wholly to Japan. It was his aim to see Thailand on the winning side.

Map of the invasion points for the Japanese on 8 December 1941 (courtesy RTAF Museum)

With Japanese forces massing at his borders and an invasion force sailing into the Gulf, Pibulsongkram mysteriously left Bangkok and could not be contacted by Japanese officials, who came to ask if he would honour the secret agreement to allow their forces unhindered transit through Thai territory.

The invasion began with amphibious landings at Songkhla, Thepa, and Pattani just after 1:00 a.m. These landings were unopposed, unlike the earlier assault against the British in Kota Baru. By mid-morning, the Japanese had around 60 aircraft, mainly fighters, on the ground at the strategically important Songkhla airfield.

Japanese landings near the mouth of the Chumphon River, Nakhon Sri Thammarat, and Prachuap Khiri Khan were opposed by the Thai military, as was an invasion of the east from Battambang in Cambodia and an air assault against Don Muang airfield. Thai air force planes flew against superior Japanese forces, losing six fighters.

At Prachuap Khiri Khan, some 120 air force personnel battled with nearly 2,000 Japanese troops for control of the airfield. The battle began around 4:00 a.m.

Just over three and a half hours later, Pibulsongkram re-appeared in Bangkok and immediately ordered a ceasefire. For the Prime Minister the tactics of a brief resistance meant he could later claim the Thais had defended their territory against the Japanese but he had reluctantly ordered a ceasefire in order to save the country from destruction.

A telegram ordering a ceasefire and surrender did not reach the defenders at Prachuap Khiri Khan until 30 hours after fighting had begun. By that time, the morning of 9 December, they had lost 42 killed, including two women. Japanese losses were estimated at around 400.

A stylised painting of the defence of Prachuap Khiri Khan (courtesy RTAF Museum)

At 11:00 a.m. on 9 December, General Percival, the British commander-in-chief in Malaya, gave permission to push troops into Thailand. At 3:00 p.m. (other sources say 5:30 p.m.) two companies of the Indian 11th Division crossed the Thai border with the aim of blocking the Japanese advance from Songkhla. It had been hoped the Thais would remain neutral, but they resisted the British advance, sniping at it all the way. The Indians moved on to Sadao, dug in, and waited for the Japanese.

At the same time, an armoured train advanced into Thailand from Pedang Besar, aiming to interdict any Japanese move from Pattani. They destroyed an important bridge and then withdrew.

Around 9:30 p.m. an advance column of Japanese engaged the Indians around Sadao, forcing them to retreat back across the Malayan border. The British destroyed a couple of bridges, but by midnight, the Japanese were crossing the border.

On 9 December, Japanese forces moved into Bangkok after an agreement was signed with the Thai government giving them right of passage through Thailand. A Japanese air group moved into Lopburi, developing the airfield as a fighter base. The Japanese also took over the telephone line between Lopburi and Bangkok as well as the local radio station.

A Japanese light tank rumbles through Bangkok

That same day, Yamashita’s forces struck out from Pattani, crossing the frontier. The British launched an air strike against the airfield in Songkhla, but only one bomber managed to get over the target. The pilot, Flight Lieutenant Arthur Scarf was wounded, but managed to return to base, crash landing without injury to his crew. He died later in hospital and was posthumously awarded the Victoria Cross. A second attack against Songkhla by six British bombers saw three shot down.

When Japanese planes sank the British warships H.M.S. Prince of Wales and H.M.S. Repulse on 10 December, the die was cast in favour of a Thai alliance with Japan. Pibulsongkram made a secret agreement with the Japanese to commit Thai forces to the invasion of Burma and on 21 December signed a 10-year treaty of alliance with Japan. The Japanese gave an undertaking to help Thailand recover what Pibulsongkram considered lost territory. At his request, the promise was made in an annex to the treaty and not revealed to the public.

Despite the alliance, Pibulsongkram remained reluctant to declare war on Britain and the United States, but Japanese pressure finally compelled him to do so on 25 January 1942. South Africa and New Zealand declared war on Thailand on the same day. Australia followed soon after.

©Duncan Stearn

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