Chapter 145: The Co-Prosperity Sphere Advances – Part1: Japanese/Thai Malayan Campaign:
Japanese Military Affairs Bureau Unit 82 (F Kikan) was formed in 1939 or 1940 and based in Taiwan to bring this about. In its final planning stages, the unit was under Colonel Yoshihide Hayashi. Intelligence on Malaya was gathered through a network of agents which included Japanese embassy staff; disaffected Malayans (particularly members of the Japanese established Tortoise Society); and Japanese, Korean, and Taiwanese business people and tourists. Japanese spies, which included a British intelligence officer, Captain Patrick Stanley Vaughan Henan and Lord Sempill also provided intelligence and assistance. Heenan's intelligence enabled the Japanese to destroy much of the Allied air forces on the ground. Prior to hostilities Japanese intelligence officers like Iwaichi Fujiwara had established covert intelligence offices (or Kikans) that linked up with the Malay and Indian pro-independence organizations such as Kesatuan Melayu Muda in Malaya and the Indian Independence League. The Japanese gave these movements financial support in return for their members providing intelligence and later assistance in determining Allied troop movements, strengths, and dispositions prior to the invasion. By 1941 the Co-Prosperity Sphere had been engaged for four years in trying to win the Chinese Civil War for Wang Jingwei. They were heavily reliant on imported materials for their military forces, particularly oil from the United States. From 1940 to 1941, the United States, the United Kingdom, and the Netherlands imposed embargoes on supplying oil and war materials to Japan and the Co-Prosperity Sphere. The object of the embargoes was to assist the Chinese and encourage the members of the Co-Prosperity Sphere to halt military action in China. The Japanese and other members of the Co-Prosperity Sphere considered that pulling out of China would result in a loss of face and decided instead to take military action against US, British and Dutch territories in South East Asia. The Japanese forces for the invasion were assembled in 1941 on Hainan Island and in French Indochina, Siamese/Thai forces were assembled in Siam itself and divisions from Cambodia, Vietnam an Yikokuo participated together with local rebels and freedom fighters of Malaysia (together 160,000 attacking forces against 140,000 allied defenders). The troop build-up in Indochina, Siam and Hainan was noticed by the Allies and, when asked, the Japanese advised that it related to its operations in China.
The Malayan Campaign began when the 25th Army, under the command of Lieutenant General Tomoyuki Yamashita, invaded Malaya on 16 November 1941. Japanese troops launched an amphibious assault on the northern coast of Malaya at Kota Bharu, supported from the 1st Siamese/Thai Army at Pattani and Songkhla that crossed the border and started advancing down the eastern coast of Malaya an the western portion of Malaya. From port and air bases in Cambodia, Vietnam and Thailand the Co-Prosperity Sphere armies, navies and air forces supported their landings and invasion. At 04:00 23 JNAF bombers attacked Singapore, the first ever air raid on the colony. It became evident to the British that Japanese bombers based in Indochina were now in range of Singapore. The Co-Prosperity Sphere forces were initially resisted by III Corps of the Indian Army and several British Army battalions. The Japanese quickly isolated individual Indian units defending the coastline, before concentrating their forces to surround the defenders and force their surrender. The Co-Prosperity Sphere forces held a slight advantage of 2:1 in numbers on the ground in northern Malaya, and were significantly superior in close air support, armour, co-ordination, tactics, and experience, with the Co-Prosperity Sphere units having fought in the Chinese Civil War. The Allies had no tanks, which had put them at a severe disadvantage. The Japanese also used bicycle infantry and light tanks, which allowed swift movement of their forces overland through terrain covered with thick tropical rainforest, albeit criss-crossed by native paths. Although the Japanese had not brought bicycles with them (in order to speed the disembarkation process), they knew from their intelligence that suitable machines were plentiful in Malaya and quickly confiscated what they needed from civilians and retailers. A replacement for Operation Matador, named Operation Krohcol, was implemented on 17 November, but the Indian troops were easily defeated by the Royal Thai Police, the 1st Siam/Thai Army and the Japanese 5th Division coming from Pattani Province, Thailand. The powerful Japanese air forces in Indochina secured the Sea, leaving the east coast of Malaya exposed and allowing the Japanese to continue their landings across Malaya unchallenged.
The defeat of Allied troops at the Battle of Jitra by Japanese forces, supported by tanks moving south from Thailand on 20 November 1941 and the rapid advance of the Japanese inland from their Kota Bharu beachhead on the north-east coast of Malaya overwhelmed the northern defences. Without any real naval presence, the British were unable to challenge Japanese naval operations off the Malayan coast, which proved invaluable to the invaders. With virtually no remaining Allied planes, the Japanese also had mastery of the skies, leaving the Allied ground troops and civilian population exposed to air attack. The Malayan island of Penang was bombed daily by the Japanese from 18 November and abandoned on 27 November. Arms, boats, supplies and a working radio station were left in haste to the Japanese. The evacuation of Europeans from Penang, with local inhabitants being left to the mercy of the Japanese, caused much embarrassment for the British and alienated them from the local population. Historians later judged that "the moral collapse and end of British rule in Southeast Asia came not at Singapore, but at Penang". However, many who were present during the evacuation did not experience it as a scramble. It was a response to an order from British High Command which had come to the conclusion that Penang should be abandoned as it had no tactical or strategic value in the rapidly changing military scheme of things at that time.
On 12 December, Major-General David Murray-Lyon of the Indian 11th Infantry Division was removed from command to little effect. By the middle of December, the entire northern region of Malaya had been lost to the Japanese. The Empie of Thailand a member of the Co-Prosperity Spher and ally of Imperial Japan, quickly resume sovereignty over the conquered sultanates in Malaya, thus consolidating their occupation. It did not take long for the Japanese and Thai army's next objective, the city of Kuala Lumpur, to fall. The Co-Prosperity Sphere army entered and occupied the city unopposed on 21 December. Singapore Island was now less than 200 mi (320 km) away for the invading Japanese and Thai army. The 11th Indian Division managed to delay the Japanese/Thai advance at Kampar for a few days, in which the Japanese/Thai suffered severe casualties in terrain that did not allow them to use their tanks or their air superiority to defeat the British. The 11th Indian Division was forced to retreat when the Japanese landed troops by sea south of the Kampar position. The British retreated to prepared positions at Slim River. At the Battle of Slim River, in which two Indian brigades were practically annihilated, the Japanese used surprise and tanks to devastating effect in a risky night attack. The success of this attack forced Percival into replacing the 11th Indian Division with the 8th Australian Division.
By mid-December, the Japanese/Thai had reached the southern Malayan state of Jahore where, on 21th December, they encountered troops from the Australian 8th Division, commanded by Mayor-General Gordon Benett, for the first time in the campaign. During engagements with the Australians, the Japanese/Thai experienced their first major tactical setback, due to the stubborn resistance put up by the Australians at Gemas. The battle (centered around the Gemencheh Bridge) proved costly for the Japanese/Thai, who suffered up to 860 casualties. However, the bridge itself (which had been demolished during the fighting) was repaired within six hours. As the Japanese/Thai attempted to outflank the Australians to the west of Gemas, one of the bloodiest battles of the campaign began on 25th December on the peninsula's West coast near the Muar River
r. Bennett allocated the 45th Indian Brigade (a new and half-trained formation) to defend the river's South bank but the unit was outflanked by Japanese units landing from the sea and the Brigade was effectively destroyed with its commander, Brigadier H. C. DUncan, and all three of his battalion commanders killed. Two Australian infantry battalions (which had been sent to support the 45th Brigade) were also outflanked and their retreat cut off, with one of the Australian battalion commanders killed in the fighting around the town of Bakri, south-east of Muar. During the fighting at Bakri Australian anti-tank gunners had destroyed nine Japanese tanks, slowing the Japanese advance long enough for the surviving elements of the five battalions to attempt an escape from the Muar area.
Led by Australian Lieutenant-Colonel Charles Andson, the surviving Indian and Australian troops formed the "Muar Force" and fought a desperate four-day withdrawal, allowing remnants of the Commonwealth troops withdrawing from northern Malaya to avoid being cut off and to push past the Japanese/Thai to safety. When the Muar Force reached the bridge at Parit Sulong and found it to be firmly in enemy hands, Anderson, with mounting numbers of dead and wounded, ordered "every man for himself". Those that could took to the jungles, swamps and rubber plantations in search of their division headquarters at Yong Peng. The wounded were left to the mercy of the Japanese/Thai and all but two out of 135 were tortured and killed in the Parit Sulong Masacre. Anderson was awarded a Victoria Cross for his fighting withdrawal. The Battle of Muar cost the allies an estimated 3,000 casualties including one brigadier and four battalion commanders. On 26 December, further Japanese landings took place at Endau, in spite of an air attack by Vildebeest bombers. The final Commonwealth defensive line in Johore of Batu Pahat-Kluang-Mersing was now being attacked along its full length. Unfortunately, Percival had resisted the construction of fixed defences in Johore, as on the North shore of Singapore, dismissing them in the face of repeated requests to start construction from his Chief Engineer, Brigadier Ivan Simson with the comment "Defences are bad for morale." On 28 December, Percival received permission from the commander of the American-British-Dutch-Australian Comand, to order a retreat across the Johore Stait to the island of Singapore.
On 30 December, the last organized Allied forces left Malaya, and Allied engineers blew a 70 ft (21 m)-wide hole in the causeway that linked Johore and Singapore; a few stragglers would wade across over the next few days. Japanese raiders and infiltrators, often disguised as Singaporean civilians, began to cross the Straits of Johor in inflatable boats soon afterwards. In less than two months, the Battle for Malaya had ended in comprehensive defeat for the Commonwealth forces and their retreat from the Malay Peninsula to the fortress of Singapore. Nearly 50,000 Commonwealth troops had been captured or killed during the battle. The Japanese Army invaded the island of Singapore on 7 January and completed their conquest of the island on 15 January, capturing 80,000 more prisoners out of the 85,000 allied defenders. The final battle before the surrender was with the Royal Malay Regiment at Bukit Candu on the 14 January. By the end of December, Heenan had been court-martialled for spying for the Japanese and sentenced to death. On 13 January, five days after the invasion of Singapore Island, and with Japanese forces approaching the city center, he was taken by military police to the waterside and was hastily executed. His body was thrown into the sea. In the next few months it became clear that the Japanese had lied to the Kesatuan Melayu Muda and other Malay Independence Movements as all of Malaya was annexed and administrated by the Thai Empire, with the exception of Singapore and other important strategic areas like Kra/Cra were the Imperial Japanese Army/Navy stationed it's own garrisons besides the Thai ones. Still the occupation of Malay by the 1st Thai Army allowed the Japanese to use most of their forces for the ongoing assault. The Co-Prosperity Sphere Malay Campaign saw 145,703 losses on allied side (7,531 killed or died of wounds, 10,000 wounded and 130,000 captured), while the Co-Prosperity Forces (mostly Japanese and Thai) had lost 9,864 soldiers, (including 3,647 killed and the rest wounded) and occurred during the same time as the Co-Prosperity Sphere invasion of the Philippines and Burma (and from there later on to Dutch East India and British India).