The British, Burmese, and Indian defense of Burma was hindered from the start. If there was ever a backwater to the British Empire, it was Burma (modern Myanmar). Traditionally, Burma was governed from India but in 1938 the British government chose (for various reasons) to administratively separate it from India and govern it directly from London. This change literally put Burma last in priority for defense spending leading up to war with Germany, and eventually Japan, and ham strung the defense of India, to whom Burma was inextricably linked. Only in late 1941 was Burma switched back to India, but by then the neglect was substantial. In any case, there was no thought of a Japanese land invasion: east of Burma lay Chiang Kai Shek’s Nationalist China, Japanese occupied French Indochina (specifically modern day Laos), and the (relatively) friendly Thailand (known as Siam until 1939) .
The Chinese relied on the Burma Road that ran from Rangoon in the south on the Bay of Bengal, north through Mandalay, and then to Wanting in China. The Burma Road was Chiang’s lifeline, virtually all of his foreign support in China’s decade long war against Japan came via that route. Though it was obvious that Japan wanted it cut, the only direct land approach was from Laos through the Shan States. This was where the bulk of the 1st Burmese Division was located, and it was populated by indigenous minorities intensely loyal to the British. When the 17th Indian Division arrived to reinforce Burma, the bulk went there. Air attack against the Burma Road was expected, and airfields lined it, running from north to south. When the Japanese attacked Malaya on 8 December, the airfields were extended further south, as the southernmost airfields on the “Tenasserim Tail” (the long narrow spit of land extending south down the Malay Peninsula) could still support Singapore. The defense of Burma had one fatal flaw: it relied on the assumption that Thailand would, at best, resist a Japanese invasion, and at worst, provide enough warning of Japanese forces crossing the country to shift forces southward. This was not the case.
Japanese forces actually invaded a small corner of neutral Thailand on 8 December, but only to quickly cross into Malaya from an unexpected direction. The Thai Army was overwhelmed, but gave a good account of itself and inflicted serious casualties on the Japanese. This was seen as definitive proof that Thailand would resist. But the Thai government knew that an invasion of Burma to cut the Burma Road was inevitable, and the Japanese were going to cross with or without Thai cooperation, and the neglected Burma would be of no help. A month later in a diplomatic coup, Japan signed a treaty of friendship with Thailand, and within days, Japanese forces were massed on the Burmese border. With no intelligence network in the until-recently friendly Thailand, the British in Burma were caught surprised.
The invasion began with air attacks all along the north/south string of airfields from Japanese airfields just a short distance to the east in Indochina. Two divisions of Japanese infantry and tanks crashed into the single Indian brigade that defended the border with Thailand along the Tenasserim Hills southeast of Rangoon. It was a surprise assault at the least likely spot along the least likely portion of the Burmese border for an attack.
The invasion of Burma was a repeat of Malaya: the road bound British would set defensive positions along the main avenues of approach, all the while looking over their shoulder and into the sky. The Japanese air superiority was complete, despite Chiang Kai Shek releasing a squadron of American Volunteer Group, better known as the Flying Tigers, for the defense of southern Burma and Rangoon. But “quantity has its own quality” works both ways, and a single squadron, no matter how good, is not enough to turn an air campaign around, particularly with the Japanese advantages in position, initiative, quality, and numbers.
Air strikes followed by banzai charges backed up by tanks would hammer the defending British, Burmese, and Indian positions while fast moving infantry columns supported by bicycle fueled logistics maneuvered on jungle tracks to establish blocking positions behind them. The first report of such a blocking position was enough to cause the forward defending unit to withdraw, lest it be cut off. Inevitably it had to conduct a hasty attack to break out. For a month the British did as much attacking to the rear as it did defending to the front.
On the 18th of February, 1942, the 17th Indian Division withdrew from the outflanked positions along the Bilin River to establish a hasty defense in depth along the last natural obstacle before Rangoon, the Sittang River, 30 miles away. There they would be reinforced by the Honey tanks of the 7th Armoured Brigade, the “Desert Rats” which were being unloaded in port after being released from the Eighth Army in the Western Desert. (the Brits had a habit in the MidEast of juggling units between theatres after a modestly successful operation, inevitably ensuring there would be no follow through. They did this after Compass, Brevity, and Crusader, all to disastrous results, though they probably had no choices at the time. It’s to Montgomery’s credit that he stood up to Churchill and the IGS and put a stop to it.) The plan was to hold the Japanese at the Sittang River, and counterattack.
However, orderly withdrawal while in contact with the enemy is the most trying of military operations, and the British had been doing it for a month. Command and control began to break down. Forward Japanese patrols were spotted nearly at the river, while 2/3rds of the 17th Indian Division was still on the far side. This created a panic at the Sittang Railroad Bridge as units clamored to get across before the main body of the Japanese arrived. On the night of 22/23 February, the division commander, who hadn’t slept for four days, was excitedly roused within minutes of putting his head down and told that the eastern bridgehead could hold no longer, and the Japanese were about to seize the bridge. This was not the case, but he didn’t know that based on the hurried and emotional reports. In order to keep the bridge from falling into Japanese hands, he ordered it blown, which trapped two full brigades on the east side of the river.
The thunderous explosion of the heavy railroad bridge was heard in Rangoon, and by every soldier and civilian within thirty miles. An eerie quiet descended on all of southern Burma, as both sides knew exactly what it meant. For the Japanese, there was no immediate reason to continue attacking, as a deliberate operation would be needed to cross the river, and the remaining Allies could be mopped up at their leisure. For the two Allied brigades, it meant there was no reason to defend: they were trapped, and their capture was inevitable… unless they swam the river.
British command and control broke down immediately and thoroughly: it was every man for himself. Thousands of British and Indian troops abandoned their equipment and streamed back towards the river bank in a rout. Only the units that were physically required to assault through Japanese roadblocks to get to the bridge retained any semblance of organization. And even they broke down upon reaching the river. Those men who could swim stripped off their uniforms and dove in. Those that couldn’t, emptied out water jugs and petrol cans to use as flotation devices or in improvised rafts. Hundreds drowned in the swift flowing water.
By the morning of the 24th, two thousand soaked men managed to make it to the far bank, few with equipment, none with boots, and most just in their underwear.
There would be no stopping the Japanese from taking Rangoon and cutting the Burma Road to China. Rangoon was ordered to be evacuated, and the remaining Allied troops withdrew north towards India.