If Lieutenant General Sir Bill Slim (he had been knighted by General Archibald Wavell, the Viceroy, the previous October, at Imphal) had been asked in January 1945 to describe the situation in Burma at the onset of the next monsoon period in May, I do not believe that in his wildest imaginings he could have conceived that the whole of Burma was about to fall into his hands. After all, his army wasn’t yet fully across the Chindwin. Nearly 800 miles of tough country with few roads lay before him, not the least the entire Burma Area Army under a new commander, General Kimura. The Arakanese coastline needed to be captured too, to allow aircraft to use the vital airfields at Akyab as a stepping stone to Rangoon. Likewise, I’m not sure that he would have imagined that a primary reason for the success of his Army was the work of 12,000 native levies from the Karen Hills, under the leadership of SOE, whose guerrilla activities prevented the Japanese from reaching, reinforcing and defending the key town of Toungoo on the Sittang river.  It was the loss of this town, more than any other, which handed Burma to Slim on a plate, and it was SOE and their native Karen guerrillas which made it all possible.

The potential of a Karenni-based resistance raised the possibility, long argued by old Burma hands, of a British armed and trained fifth column operating behind Japanese lines for the purpose of gathering battlefield intelligence and undertaking limited guerrilla action. Slim had long complained about the poor quality of the battlefield intelligence (as opposed to the signals intelligence, about which he was well provided) that he and his Corps commanders received. He was concerned, among other things, about knowing ‘what was on the other side of the hill’, the product of information provided – where it existed – by effective combat (ground and air) reconnaissance. There was no shortage of organisations attempting to assist in this task – at least twelve – but their coordination was poor and most reported to SEAC or parts of India Command, rather than to 14 Army. Slim dismissed most of these as ‘private armies’ which offered no real help to the task of defeating the enemy on the battlefield. One of the groups, part of Force 136 (i.e. Special Operations Executive, or SOE), which had operated in front of 20 Indian Division along the Chindwin between 1943 and early 1944 under Major Edgar Peacock (and thus known as ‘P Force’) did sterling work with local Burmese and Karen agents reporting on Japanese activity facing 4 Corps. Persuaded that similar groups working among the Karens in Burma’s eastern hills – an area known as the Karenni States – could achieve significant support for a land offensive in Burma, Slim (to whom Mountbatten transferred responsibility for Force 136 in late 1944 for this purpose) authorised an operation to the Karens. Its task was not merely to undertake intelligence missions watching the road and railways between Mandalay and Rangoon, but to determine whether they would fight. If the Karens were prepared to do so, SOE would be responsible for training and organising them as armed groups able to deliver battlefield intelligence directly in support of the advancing 14 Army. The resulting operation – Character – was so spectacularly successful that it far outweighed what had been achieved by Operation Thursday the previous year in terms of its impact on the course of military operations in pursuit of the strategy to defeat the Japanese in the whole of Burma. It has been strangely forgotten, or ignored, by most historians ever since, drowned out perhaps by the noise made by the drama and heroism of Operation Thursday, the second Chindit expedition. Over the course of Operation Extended Capital some 2,000 British, Indian and Burmese officers and soldiers, along with 1,430 tons of supplies, were dropped into Burma for the purposes of providing intelligence about the Japanese that would be useful for the fighting formations of 14 Army, as well as undertaking limited guerrilla operations. As historian Richard Duckett has observed, this found SOE operating not merely as intelligence gatherers in the traditional sense, but as Special Forces with a defined military mission as part of conventional operations linked directly to a strategic outcome.  For Operation Character specifically, about 110 British officers and NCOs and over 100 men of all Burmese ethnicities, dominated interestingly by Burmans (which now also included three-man Jedburgh Teams) mobilised as many as 12,000 Karens over an area of 7,000 square miles to the anti-Japanese cause. Some 3,000 weapons were dropped into the Karenni States. Operating in five distinct groups (‘Walrus’, ‘Ferret’, ‘Otter’, ‘Mongoose’ and ‘Hyena’) the Karen irregulars  trained and led by Force 136, waited the moment when 14 Army instructed them to attack.

Between 30 March and 10 April 1945, 14 Army drove hard for Rangoon, led by Lieutenant General Frank Messervy’s 4 Indian Corps in the van. Pyawbe saw the first battle of 14 Army’s drive to Rangoon, and it proved as decisive in 1945 as the Japanese attack on Prome had been in 1942. Otherwise strong Japanese defensive positions around the town with limited capability for counter-attack meant that the Japanese were sitting targets for Allied tanks, artillery and airpower. Messervy’s plan was simple: to bypass the defended points that lay before Pyawbe, allowing them to be dealt with by subsequent attack from the air, and surround Pyawbe from all points of the compass by 17 Indian Division before squeezing it like a lemon with his tanks and artillery. With nowhere to go, and with no effective counter-attack potential, the Japanese were exterminated bunker by bunker by the Shermans of 255 Tank Brigade, now slick with the experience of battle gained at Meiktila. Infantry, armour and aircraft cleared Honda’s primary blocking point before Toungoo with coordinated precision. This single battle, which killed over 1,000 Japanese, entirely removed Honda’s ability to prevent 4 Corps from exploiting the road to Toungoo. Messervy grasped the opportunity, leapfrogging 5 Indian Division (the vanguard of the advance comprising an armoured regiment and armoured reconnaissance group from 255 Tank Brigade) southwards, capturing Shwemyo on 16 April, Pyinmana on 19 April and Lewe on 21 April. Toungoo was the immediate target, attractive because it boasted three airfields, from where No. 224 Group could provide air support to Operation Dracula. Messervy drove his armour on, reaching Toungoo, much to the surprise of the Japanese, the following day. After three days of fighting, supported by heavy attack from the air by B-24 Liberators, the town and its airfields fell to Messervy. On the very day of its capture, 100 C-47s and C-46 Commando transports landed the air transportable elements of 17 Indian Division to join their armoured comrades. They now took the lead from 5 Indian Division, accompanied by 255 Tank Brigade, for whom rations in their supporting vehicles had had been substituted for petrol, pressing on via Pegu to Rangoon. The bold attack in depth that 4 Corps advance represented, the tip of 14 Army’s spear, as remarkable. Armour, infantry and tracked artillery worked in combined teams with intimate support provided in the air by continuous fighter-ground attack patrols linked by radio to the leading tanks. Each stage of the attack was undertaken to confuse Kimura; to act before he could respond to the previous threat, resulting in the Burma Area Army remaining in a state of command confusion for much of 1945. The single operational objective – to get to Rangoon before the rains fell – was prioritised before all else. Aerial resupply was a strategic function of SEAC, organised by Mountbatten in a single Air and Ground Supply Committee in March 1945 that prioritised air transport strictly in accordance with strategic priorities across the whole theatre. An additional strategic consideration needs to be recalled. Slim recognised that if the Japanese were able to hold Toungoo, and thus prevent 14 Army makings its way beyond this point, Kimura would not need to evacuate Rangoon. If Rangoon were defended, Operation Dracula would be opposed, with serious consequences in terms of casualties. Defeating the Japanese at Toungoo would, it was hoped, force Kimura to evacuate Rangoon beyond the Sittang to avoid being caught in a 14 Army/Operation Dracula pincer.

The contribution of Operation Character to the advance by 4 Corps to Toungoo and beyond was battle-winning. By April 1945 the Karen irregulars harried the 50,000 Japanese in the hills, directing air strikes, providing close reconnaissance of targets for No. 224 Group’s aircraft. Their attacks, beginning in early April, were coordinated by HQ 14 Army to coincide with the advances of elements of 4 Corps, and were focused on preventing the Japanese 18 Division from reaching and reinforcing Toungoo before the arrival of 5 Indian Division. To get to Toungoo, 18 Division had to pass through areas of jungle hills to the north-east and east entirely dominated by the Force 136. By means of repeated ambushes the Japanese were fought every step of the way. Large amounts of detailed target information was radioed through for use in attacks by the air force. The official historian of SOE observed that, ‘in the week before the fall of Rangoon [2n May 1945] almost all their long-range fighter-bombers were employed on Force 136 targets, and that so many high-grade reports came in that it was impossible to act on them all. There were many notable successes, the principal being an attack on the railway station at Pyu which coincided with the arrival of a troop train and caused over 1,000 casualties. No. 221 Group RAF was so impressed with Force 136’s later intelligence that they proposed that when operations began in Malaya at least one squadron should stand by to carry out immediate strikes when a mobile target was reported – something that had not been done in Burma.’ Roadblocks, ambushes and demolitions held up the Japanese 18 Division’s cross-country advance to Toungoo in the area of Mawchi, 50 miles east of Toungoo. In his immediate report on operations Slim described the operational effect of the Karen irregulars:

Our own levies led by their British officers were a most valuable asset and had a real influence on operations. They were tactically controlled by wireless from Army Headquarters, told when to rise, the objectives they should attack, and given specific tasks. They could not and were not expected to stand up to the Japanese in pitched battles but they could and did in places harry them unmercifully. Their greatest achievement was the delaying of the 15th Japanese Division on the Loikaw-Mawchi area, thus enabling IV Corps to reach Toungoo first, but they have rendered almost equally valuable services. They had an excellent jitter effect on the Japanese, who were compelled to lock up troops to guard against attacks on the lines of communication.

The work of Force 136, in particular in operations such as Operation Character, delivered exactly the sort of support Slim demanded of Special Forces, which was to assist the work of the main, or conventional forces, by gathering close target reconnaissance and mounting attacks on enemy rear echelons, lines of communications and other such ‘soft’ targets by means of ambushes and hit-and-run raids. Without the operations of these SOE-led Karen guerrillas in blocking the Japanese 56 Division’s attempts to defend Toungoo and 18 Division’s efforts to reinforce it, 14 Army would almost certainly have been stopped in its tracks. If this had happened, it is reasonable to surmise that Kimura would not have felt the need to evacuate Rangoon, with all the attendant difficulties for Operation Dracula of having to assault a defended capital just as the monsoon struck. The estimate of Japanese killed by Operation Character was 11,874, far more than those killed by the soldiers of 4 and 33 Corps. As the historian of SOE Richard Duckett rightly asserts, Operation Character achieved dramatic operational effect at ‘a low cost in terms of men and equipment’ by helping ‘to protect the flank of Slim’s XIV Army as it advanced into southern Burma … [By] raising the local population and operating in difficult terrain, the Character teams assisted regular forces by inflicting significant casualties upon the Japanese, as well as psychological damage.’

With Toungoo secured, 33 Corps pressed hard down the Irrawaddy, breaking the western end of Kimura’s defence line. With Kimura distracted by Toungoo, Evans’ 7 Indian Division struck at Yenangyaung on 22 April, before driving hard down the road to Prome. Simultaneously, Gracey’s 20 Indian Division took Taungdwingyi in a surprise attack, thwarting any escape by the remnants of Sakurai’s 28 Army over the Pegu Yomas, thus preventing their involvement in the battle for Toungoo. On 2 May, Prome fell.

It was the loss of Toungoo that persuaded Kimura that he could not hold Rangoon. He needed to get the bulk of his army onto the eastern side of Pegu to offer them any hope of fighting a battle for Sittang and Tenasserim. Accordingly, he rushed up troops of divisional strength to defend Toungoo just as 17 Indian Division and the Shermans of 255 Tank Brigade arrived. On 29 April, Cowan’s division reached the town and cut it off from the Sittang, two brigades crossing the river despite Japanese bridge demolitions and strong resistance. Cowan’s arrival in the town coincided with that of the monsoon rains. The Japanese defence collapsed, and Cowan’s triumphant division now turned right and made its way towards Rangoon.

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