Bill Slim and the reasons for victory in India (1944) and Burma (1945)

A still from battlefield cinematography of an Indian Army combined arms attack on Pyinbongyi, Burma, April 1945

Tonight I’ll be attending a Burma Star Memorial Fund event in London to remember the end of the war in the Far East in 1945. I thought today was therefore the perfect opportunity to explain how Slim was able to secure victory against the Japanese in India in 1944 and Burma in 1945.

‘Burma and the Birth of Modern Warfare’ is the subtitle to my 2004 book and PhD about General Slim’s command of the 14th Army in Burma during the last war, titled ‘Slim, Master of War’, a use of Sun Tzu’s description of a ‘heaven-born’ commander. It may appear a rather grand claim, and perhaps it is, but the purpose of the subtitle reflects that fact that Slim's conduct of operations in India and Burma in 1944 and 1945 represented an entirely new style of warfighting to that experienced by the British Army during the war. Instead of looking back to the lessons of World War One, Slim's conduct of operations looked forward to reflect a style of warfare that would only be adopted as formal doctrine by the British Army in the 1980s. In the mid-1940s it remained alien to the vast bulk of similar British military experience and understanding.

My argument wasn’t not that Slim was the best general who had ever commanded men in the history of warfare. That may or may not be true, but for the sake of my argument is irrelevant. My proposition, rather, is that:

‘Slim was the foremost British exponent in the Second World War of the ‘indirect approach’ and that in his conduct of operations in 1944 and 1945 he provided a clear foreshadowing of ‘manoeuvre warfare’.

My idea, which first saw expression in my 2004 book, has been developed since then in my subsequent writings, including that of Japan's Last Bid for Victory, which deals with the great events in the Assam and Manipur in 1944 (2011) and A War of Empires (2021). A major reason for the continuing amnesia in British military thinking about the warfighting characteristics of the Burma Campaign – apart from the fact that it is a long way to go for a staff ride – seems to be the fact that Slim’s style of warfighting remained largely alien to the British Army’s doctrinal precepts until the late 1980s. Until then, Slim’s strategic conceptions had been considered an aberration, and Slim himself regarded merely as the epitome of a fine military leader, and nothing more. Then, in a doctrinal revolution which began in the 1980s, the old firepower-based foundations – which themselves were largely a product of Montgomery’s approach to war in 1944 and 1945 – in which the supreme military virtue was the effective and coordinated application of force, were replaced. This revolution in doctrine and thinking about warfighting exchanged the old foundations with new ones based on an entirely different conception, that of manoeuvre at the operational level of war, in which notions of subtlety, guile and psychological dislocation came to be emphasised in an entirely new and refreshing way. My belief is that it was the effective and pragmatic employment of manoeuvre at the operational level of war by Slim in Burma that was the direct cause of the extraordinary victories the 14th Army achieved in 1944 and 1945 and which led to the two greatest defeats the Japanese Army suffered in the field in the Second World War, the first at Imphal-Kohima in India in 1944 and the second at Mandalay-Meiktila in Burma in 1945. My argument I suppose is that Slim’s exercise of command in Burma makes him not merely a fine example of a ‘manoeuvrist’ commander but in actuality the template for modern manoeuvrist command.

One of the great things about being an historian is that we can tidy up history, by organising it into helpful epochs. The Burma Campaign can be broken down into four major phases. The first was the retreat from Burma in 1942. This was followed by a period of recovery during 1943 which saw the first Chindit expedition into Burma under Orde Wingate and extraordinary efforts to rebuild an army conditioned to defeat. The third period was the great turning point battles of Arakan, Kohima and Imphal in 1944 and the fourth, the recovery of Burma itself in 1945.

The Japanese attack began in late December 1941, with the aerial bombardment of Rangoon, followed up by a decisive blitzkrieg-type thrust from Thailand by two fully formed, well-trained and aggressive Japanese infantry divisions of the Japanese 15th Army in February 1942. The tiny British garrison was driven north into India in what became the longest retreat in the long history of the British Army; some 1,100 miles to Imphal, which was reached at the end of May 1942. But there were a number of striking features about that retreat which are worth noting. First, whilst the period leading up to the loss of Rangoon in March – i.e. the first month of the campaign was an unmitigated disaster, involving the loss of most of the 17th Indian Division on the wrong side of the Sittang Bridge, the remaining period was, on reflection, not entirely awful. Badly outnumbered, with the civilian population largely against them, with roads clogged with thousands of Indian refugees, with virtually no air cover and in the desperate 120° heat of the Burmese summer, what had hurriedly become the 1st Burma Corps, formed itself quickly into a cohesive fighting whole and fought a vigorous and aggressive retreat. Major General Bill Slim was hastily flown in from Iraq to take command in the middle of March. The professionalism of the units involved – some British, some Indian and some Burmese – was without doubt the primary reason for the success of the withdrawal. True, the British had been thrown out of Burma, but in the process the Japanese 15th Army had been given such a bloody nose that it was unable to consider offensive operations into India from Burma for another two years. The retreat was a failure, but it was by no means a disaster, and certainly did not constitute a second Singapore. It also gave Slim, and others, a perfect schooling in Japanese tactics and an understanding of the Japanese military mind that was to stand him, and them, in very good stead later on.

The second period was 1943. Disaster still stalked British arms during the year, with a poorly planned and half-hearted offensive along the Arakan coastline, petering out in some ignominy in May 1943. Brigadier Orde Wingate’s first Chindit expedition, whilst also to all intents and purposes a desperate and unsuccessful venture, was spun very effectively by GHQ India into a propaganda story that still today holds many in its thrall. But 1943 was significant in a number of ways for the future of British military operations against the Japanese. A range of changes were made to the way in which the British thought about the task they faced. First, a combined joint HQ was established to take charge of all offensive operations against the Japanese across the whole of South East Asia. To be successful strategically, the theatre needed a joint and combined command structure. This was created in October 1943, without any template or precedent, and it proved to be a watershed in Allied fortunes in the Far East. Without it the American air resources necessary to enable Slim’s forces to move as far and as fast as they did, without the usual reliance on land-based lines of communication, would not have ever been made available. South East Asia Command, or SEAC, had a British Admiral - Lord Mountbatten - as ‘supremo’ and an American General - Stilwell - as his deputy. Responsibility for supporting SEAC with trained manpower and with the necessary administrative and logistical support to sustain operations across the theatre was given to GHQ India. It proved to be absolutely the right thing to do, and the benefits it brought were immeasurable.

Second, a single army was created – the 14th Army – with responsibility for confronting the Japanese on land, and command was given in October to the newly promoted Lieutenant General Bill Slim, who until then, and from the time of the retreat from Burma, had been the commander of 15 Corps, one of the two Indian corps facing the Japanese on the eastern Indian frontier. There were not a few at the time who were sceptical about the appointment. Slim was virtually untried. He had won no victories, was relatively unknown outside of the rather insular circles of the Indian Army, had been dismissed as second-rate by at least one of his superiors and had in fact been party to successive British defeats in the field since the retreat from Burma in early 1942. What is more, he now commanded an army that had been comprehensively and regularly beaten in two years of bitter experience at the hands of the Japanese. On the face of it, and to the uninformed observer, Mountbatten’s appointment of Slim to command the renamed Eastern Army could hardly have seemed more ominous.

But those who had the eyes to see had seen how Slim had already transformed 15th Corps, through the monsoon of 1943, into a formidably trained and highly motivated formation. What he had managed to do with 15th Corps, against all the odds and despite the predictions of the gainsayers – and there were many – was little less than remarkable. Amongst other things he had fully integrated his air and land headquarters; he had imposed a rigorous training regime on all his units, insisting upon live field firing in realistic conditions for all troops and he had radically improved the quality of the lines of communication and the administration of the system that supplied his corps. He also improved the quality of information given to the troops, the core of which was a framework – moral, intellectual and physical – in which soldiers were told what they were fighting for, the reasons for the commitment asked of them, and an honest-as-possible appreciation of how the army was going to help them to achieve this. Few British commanders at the time in India showed that they had the personal bottle to throw out what didn’t work, and without regard for prejudice or tradition, to get on and apply that which did. Slim was one such, and he surrounded himself with those who thought and acted likewise.

So, despite the failures earlier in the year, as 1943 came to an end it was apparent to many that the seeds of eventual success against the Japanese had been sown. Building on what Slim had achieved in 15 Corps huge changes were made to the army’s ability to fight effectively in jungle and plain, in monsoon rain and summer heat, despite the prevalence of diseases like scrub typhus and malaria. The most immediate difficulty lay in developing the confidence of the Army so that it would be able to take on the Japanese in battle, and win. The second was to overcome the enormous physical problems posed by geography and climate. Considered together, in their scale and complexity they posed in my view the greatest problem ever faced by a British commander in war. In 15 Corps Slim had shown that he had the mettle to overcome these issues. With Mountbatten at the helm of SEAC, Auchinleck of India Command, and Slim of the 14th Army, extraordinary improvements were made in virtually every area: of strategy, organisation and leadership, tactics, training and morale, changes that transformed the nature of the army in late 1943, from one that had previously been cowed in the face of the enemy to one that decisively defeated the Japanese in 1944 and 1945. It now needed to be seen whether these seeds would grow and produce fruit.

The third period saw, at long last, a series of great turning-point battles during 1944 in which the Japanese were bettered in the Far East for the first time. Some key characteristics of Slim’s approach to war first saw the light of day in the course of these battles, and it is worth dwelling briefly on them now.

First, along the Arakan coastline a major Japanese offensive was convincingly destroyed by Slim’s 15th Corps in February and March 1944. One of the questions facing Slim in 1943 was how to overcome the devastating Japanese tactics of envelopment and infiltration, tactics which in the past had exploited every weakness in the British Army’s doctrine of linear defence. The solution to this problem developed in detail during the monsoon of 1943. Slim’s plan involved the age old idea of a defensive area or ‘box’ which could be formed by units when they had been surrounded by the enemy. The difference now was that they would be resupplied by air. When surrounded, units were trained to withdraw immediately into a defensive posture that then formed the strong pivot of future action, and which struck back aggressively against their attackers. These tactics meant that the Japanese could themselves be attacked and cut-off from their own supply lines. All troops – from fighting formations to supporting units of every description without exception – were trained to turn themselves instantly into self-sufficient strongholds and to stand fast if bypassed. This ability to stand and fight in strongholds would provide the second element, namely an anvil against which the hammer of the army or corps reserves could smash in counter-attack and thus complete the destruction of the enemy that the strongholds had begun.

New tactics were also required for the attack. Slim appreciated only too clearly that the fatal errors of the past had included unimaginative attacks on narrow frontages, and the repeated use of conventional frontal attacks by infantry, even when fully coordinated with air and artillery, and well supported by firepower. At this stage he emphasised to his divisional and brigade commanders that frontal attacks were to be avoided in favour of attacks from the flanks and the rear, and that the best means of overcoming Japanese positions was by adopting the envelopment tactics so decisively exploited to that date by the Japanese themselves. This would have the effect of cutting off the defenders supply lines and thereby placing pressure on them where they were most vulnerable. In the development of these tactics two key principles stood out. First, attacks should be made at places where the Japanese were weakest and second, great rewards could be reaped by being unpredictable.

Envelopment and infiltration were, for many in the British-Indian Army in 1943, unconventional and even unsound notions. At the very least they entailed risk, unacceptably high levels of low-level command initiative, high levels of individual and collective training and an acceptance of operating without clearly defined supply lines.

Such tactics demanded a number of basic prerequisites. The first was for battalion, brigade and divisional commanders of high quality, men who would hold their nerve in times of acute crisis, and who could inspire their soldiers to give of their last ounce of commitment and energy. It was equally important for leaders to want to take the initiative from above and to encourage their subordinates to do the same. Officers who demanded freedom for themselves but refused to give it to their subordinates were simply nuisances on the battlefield. Leadership in battle became the sole determining factor in an officer’s selection for command, and the 14th Army – and Slim personally – exercised a ruthless weeding of individuals who were not up to the mark.

The second was for well-trained, motivated and confident troops. Units that were able to infiltrate through and around Japanese positions at night, separated from their regular supply chain, and able to form quick defensive ‘boxes’ when threatened in turn by Japanese infiltration, needed to be exceptionally confident in their fighting skills, their tactics and their leaders.

Such could be achieved only as the result of hard and realistic training. Even administrative and support units had to be able to stand fast in the event of encirclement and defend their perimeter against attack. The means of securing this confidence was relentless practice, and a high casualty rate during training – both physical and psychological – was accepted as necessary if the point of the lance were to remain sharp.

The third was for an efficient air transport system. The success of Slim’s ‘pivot’ idea depended entirely upon the ability of the defended bastions to be supplied from the air with everything they required for their defence. This in turn required not just a substantial transport aircraft fleet but local air superiority as well. Until he had the aircraft he had no choice but to ignore them for planning purposes. But both Slim and Giffard worked hard during this period to inculcate in the minds of all troops a sense of what Slim described as ‘air-mindedness’. In this they were remarkably successful. In time all who served in Burma came to regard the supply of units from the air as no more unusual than resupply by rail or road. Commanders also came to regard the support provided by ground attack aircraft and bombers as indispensable – and as readily used – as they had traditionally regarded the use of mortars and artillery.

The Arakan battles in early 1944 were the first opportunity to put into practice Slim’s ideas. Following the initial Japanese attacks a British counter-attack by the Corps reserve began immediately, while units cut-off in the melee were ordered to congregate in divisional ‘boxes’. British drill had now changed, as Slim had planned. Units stayed where they were and, supplied by air, fought off ferocious and increasingly desperate Japanese attacks as the days passed.

Although they made frantic efforts the Japanese failed to breakthrough, Slim’s reserves moved down quickly from Chittagong and in weeks the Japanese supply system collapsed completely. The Japanese offensive in Arakan thus ended in serious failure. The Arakan battles were the first of the turning points in 1944: for the first time a major Japanese attack had been heavily defeated in pitched battle by British and Indian formations and their well-tried envelopment tactics successfully defeated by air supply and battle discipline on the ground. Heavy losses had been inflicted on the enemy on the ground and in the air, and the myth of Japanese invincibility exploded for ever. The effect of the victories on the morale of 14 Army was very marked; indeed, the Arakan battles steeled and gave confidence to the Army for the first time.

The offensive in Arakan was followed by a major invasion by the Japanese of Assam, which led to the battles of Kohima and Imphal. To cut a long story short, Slim adopted a strategy which many in India at the time regarded as risky and foolhardy. He decided to allow the Japanese to advance deep into India rather than to defend in forward positions along the Chindwin. His approach wasn’t conventional, but it was undoubtedly correct. Slim’s plan was to draw the Japanese 120 miles across the Chin Hills. Once there, they would be mauled in assaults on British prepared positions, attacked by mobile counter-penetration forces strong in artillery and armour and heavily supported from the air. Success was never guaranteed, however. Three months of vicious fighting raged across the mountainous terrain that skirts the north, east and south of the Manipur Plain, which included in the north the hilltop village of Kohima. But by May – two months after the initial Japanese advance had begun, Slim had the Japanese where he wanted them. By early June the Japanese offensive collapsed entirely. Tired, at the end of long and difficult lines of communication across mountain and jungle, and battered remorselessly by relatively fit and well equipped units, which now included a total of four Indian Divisions and two armoured brigades, Slim broke out of the Imphal encirclement and began his own counter-attack towards the Chindwin, pushing the Japanese back slowly but inexorably as he did so.

On 19 August the last organised enemy units quit India. During the battles at Imphal and Kohima, the Japanese suffered a crushing defeat. 15 Army sustained 53,500 casualties out of a total of 84,300 men – of these 30,000 were killed, missing or had died, many of starvation or disease. British casualties were under 16,700, of which a quarter had been incurred at Kohima. The Japanese defeat was decisive and the initiative in the Burma theatre now passed for the rest of the war to the allies. The way back to Burma had been uncovered.

The fourth and final phase of the Burma Campaign took the 14th Army from its pursuit of the Japanese out of India in 1944, across the Chindwin and Irrawaddy rivers in early 1945, the decisive battles around Mandalay and Meiktila in March 1945, and the armoured dash to Rangoon – a distance equivalent to that between Paris and Marseille – in one month in April and early May 1945. The subject of a brilliant new book by Jack Bowsher, it was an operation of staggering superlatives and extraordinary achievements, but despite this has been largely forgotten in the historiography of WW2. Until Jack’s book, for example, there has been no single authoritative account of either the great Mandalay-Meiktila battles, nor of the dramatic armoured and airborne advance on Rangoon. Far less dramatic operations in North West Europe boast an embarrassment of literary riches by comparison.

That, then, is the broad historical context through which we can judge Slim’s manoeuvrist credentials. My contention that Slim was the preeminent model of manoeuvrist command is easily proved, I believe, by comparing Slim’s exercise of command in India and Burma with current British Military Doctrine. A number of the characteristics of modern doctrine would, I hope, already be very clear to you from what I have said so far.

First, the 14th Army was the only truly joint formation in the British armed forces during WW2. Nothing else, in North Africa, Italy or North-West Europe came close to it. Slim insisted on nothing less than full integration. Not only were headquarters joint, but operational and tactic delivery was also joint. At every level of command air and land headquarters were completely interlinked. I became convinced of this fact when I discovered that the RAF and the Army even shared messes! Strategic air transport, winning the air war, the operational reach and flexibility provided by air power underwrote Slim’s conception of battle, to the extent that the senior RAF officer in the theatre ruefully concluded in 1945, and I quote, that:

‘Slim was quicker to grasp the potentialities and value of air support in the jungles of Burma than most Air Force officers.’

There was no snobbery and no shibboleths with Slim: if it worked, it was pressed into action.

Arguably the most decisive element in the whole air power equation in Burma was his successful employment of air transport to overcome the enormous problems posed by the poor ground lines of communication. Despite limited payloads, atrocious terrain and weather conditions, the effect of Japanese interdiction and limited range, transport aircraft provided 14 Army in Assam, the Arakan and then in Burma with the means to continue fighting when the physical constraints of terrain prevented re-supply by land. In fact without air supply victory could not have been achieved in Burma.

The long battles for Imphal and Kohima in 1944 demonstrate how essential the aerial dimension of warfare was to Slim’s plans. From April to June 1944, all resupply to the Corps box at Imphal and the beleaguered garrison at Kohima to the north, came by air. During this period some 12,550 reinforcements and 18,800 tons of supplies were delivered to Imphal and about 13,000 sick and wounded and some 43,000 noncombatants evacuated. During the second Chindit expedition in March 1944, 30,000 men and 5,000 animals were transported by air and maintained for three months in the largest airborne operation of the Second World War. Likewise in 1945 the divisional push from Meiktila to Rangoon – some 700 kilometres in 5 weeks – was also sustained entirely by air. The success of the airlift was made possible only by allied air superiority, which enabled transport aircraft to be used with relative safety close to the enemy.

Slim himself described air transport to be 14 Army’s distinctive contribution ‘towards a new kind of warfare.’ There was no doubt in Slim’s view that ‘Ours was a joint land and air war; its result, as much a victory for the air forces as for the army.’

A second characteristic of Slim’s approach to war is that he aimed always to apply strength, in the form of combat power, against weakness, rather than against strength. In everything he sought to exploit subtlety and guile. At the tactical level he berated those who in 1943 were still trying to solve the problems provided by Japanese defensive tactics by massing infantry for assaults on narrow frontages. At the operational level of war one of the best examples of Slim’s approach was Operation Extended Capital in Burma in early 1945. Because of the significance of this particular operation I will pause to describe it here in more detail. It was without doubt one of the classic accounts in the history of war of the power of manoeuvre to entirely destabilise the whole basis on an enemy’s plan. This isn’t just me saying so. General Kimura, commander of the Burma Area Army, described it as the ‘masterstroke of the war.’

Slim’s original plan was to fight the main strength of the Japanese army on the Shwebo Plain, a dry, flat plain between the loops of the Chindwin and Irrawaddy. Not only would the terrain be well suited to the deployment of armour, for which the Japanese had little effective reply, but the Japanese would be trapped with the river-line at their back. Slim had assumed that the Japanese would be unprepared to make a voluntary withdrawal. The scene was set for Slim to be able to deploy his superior mobility and firepower to destroy the main Japanese army in Burma.

By the end of the year, however, it became apparent that the Japanese were not going to conform to Slim’s plan for the battle, and General Kimura had seen the trap which his forces would be caught in if they attempted to stand and fight in the Shwebo Plain. Showing unusual flexibility and moral courage Kimura promptly withdrew 15 Army behind the Irrawaddy. Kimura hoped, not without reason, to be able to smash Slim’s army as it attempted to cross the river, which in itself presented an immense obstacle to the British. He would then counter-attack and destroy Slim as the British withdrew during the monsoon to the Chindwin.

Kimura’s move behind the Irrawaddy destroyed at a stroke Slim’s plan. Undaunted, and recognising the supreme importance of destroying Kimura’s army rather than taking ground for its own sake, Slim came up with another plan. In basic outline, his new plan (Operation Extended Capital) entailed crossing the Irrawaddy and fighting the decisive battle in February in the plain around Mandalay and the low hills around Meiktila, the key enemy air and supply base in Central Burma. Both the road and rail links between Mandalay and Rangoon ran through Meiktila. If Meiktila fell, the whole structure of the Japanese defence of Central Burma would collapse.

But this meant that 14 Army had to cross a great river which the enemy were holding in considerable strength throughout its length. Since 14 Army did not possess enough equipment to make a strongly-opposed main crossing feasible and to avoid a frontal assault against strength, Slim proposed to make more than one crossing and then deceive the Japanese as to where the real assault in strength was to be made. This was a very audacious concept. Slim decided that if he made a sufficiently strong crossing north of Mandalay, this would draw in Kimura’s forces, whilst the main crossing could be made south of Mandalay, directed against the Meiktila base.

Slim intended secretly to switch 4 Corps from the left to the right flank of his army, moving it down the Gangaw Valley, building its own road through forest and jungle as it went. It would then mount a sudden, overpowering assault over the Irrawaddy and push an armoured strike force through to Meiktila. The capture of this focal communication area, with its dumps and airfields, would sever the lifeline of 15 and 33 Armies to the north.

Slim hoped that these moves would completely unhinge Kimura’s front and disrupt the balance of his forces. If successful, it would lead to the destruction of Kimura’s army. It relied for success upon secrecy, on speed and on taking huge administrative risks. He had to somehow get 4 Corps and its tanks the 300 miles to the Irrawaddy bridgehead, through difficult jungle country and without the benefit of a proper road, and when they got there, to cross one of the worlds greatest rivers. Somehow, 14th Army managed it, in the face of innumerable logistical difficulties, and throughout Kimura had no inkling that he was not faced with two corps north and west of Mandalay.

In the third place Slim’s sole interest was that of destroying the enemy at the expense of all else. He had no interest whatsoever in the capture of ground for its own sake. During the ill-fated Arakan operations in 1943 the British had a dangerous obsession with holding ground which led to the 14th Indian Division becoming hopelessly extended on a long line of communication, in difficult country, ripe for the inevitable Japanese outflanking, encirclement and disaster.

In the fourth place Slim’s primary object was to defeat the Japanese by destroying his will by seizing the initiative and by applying constant and unacceptable pressure at the times and places that the enemy least expected. Operation Extended Capital was focussed on persuading General Kimura that he was faced by insurmountable odds precisely where he was most vulnerable. Slim’s intent was to persuade his enemy that the battle was lost rather than necessarily to prove it to him through the physical destruction of his army. Slim did not confront Kimura with the bulk of his combat power in the teeth of the Japanese defence along the Irrawaddy to the north of Mandalay. Rather, Slim’s feint in the north and his bold attack in the south to seize Meiktila surprised and dislocated the enemy – at every level of command – so that the Japanese were finally forced to admit that the battle could not be won.

Finally, the 14th Army made itself the master of the tempo of events. In May 1944, as victory edged nearer at Imphal and Kohima, Slim launched his forces in aggressive counter-action and pursuit, throughout seeking to prevent the Japanese from organising an effective defensive plan, and denying them any opportunity to recover. Indeed, throughout the battles for Meiktila and Mandalay the Japanese were out-paced in every respect. The commander of 7 Indian Division, Lieutenant General Geoffrey Evans, remarked:

‘No sooner was a plan made to meet a given situation than, due to a fresh move by Slim, it was out-of-date before it could be executed and a new one had to be hurriedly prepared with a conglomeration of widely scattered units and formations. Because of the kaleidoscopic changes in the situation, breakdowns in communication and the fact that [the Japanese] Burma Area Army Headquarters was often out of touch with reality, many of the attacks to restore the position were uncoordinated.’

So in every characteristic of manoeuvre warfare the evidence is clear that Slim fought his war in Burma using its principles. When setting out on my research a number of years ago, I compared the command characteristics of a manoeuvrist general, described in British Military Doctrine, with Slim’s exercise of command in Burma. In every instance the match was perfect.

First, the ability of Slim to remain calm and seemingly unperturbed in the face of the most acute crises, and at times when military crises seemed relentless and insurmountable, was astonishing. A staff officer of his who saw him at first hand during the desperate 1,100 mile retreat from Burma in 1942:

’Rock-like and imperturbable, he never lost his temper and when looking into the jungle of possibilities, he could disentangle the irrelevancies and select the vital one’.

His calmness in crisis acted to highlight Slim’s own extraordinary powers of leadership. He was a natural leader of men who possessed an ability to inspire them to do their utmost for the common cause.

Second, he thought quickly and acted originally. In Professor Norman Dixon’s classic book On the Psychology of Military Incompetence, he notes that key ingredients in military blunders by senior officers in war have been a predilection for frontal assaults, often against the enemy’s strongest point, a belief in brute force rather than the clever ruse, and a failure to make use of either surprise or deception. We have seen that Slim was not temperamentally or professionally disposed towards an attritional, or confrontational approach to warfighting, an approach he had eschewed from his earliest days of soldiering and which he had regarded with horror whenever he saw it applied. An anecdote from Slim’s early career pays testament to this. A Sergeant Major, noticing Slim’s perusal one day of the ‘Principles of War’ listed in a military manual, told him: “There’s only one principle of war and that’s this. Hit the other fellow, as quick as you can, and as hard as you can, where it hurts him most, when he isn’t looking!” Slim never forgot this simple lesson. Consequently, both deception and surprise were employed as the keynotes of Operation Extended Capital and acted decisively to attack the will of the enemy.

Slim’s style of command produced an unusual propensity to delegate. If they were up to the job, Slim allowed his corps and divisional commanders their heads, and they likewise their own subordinate commanders. Burma in 1944 and 1945 was a war of junior officer initiative unparalleled in British experience of war elsewhere between 1939 and 1945. Slim told his subordinates what to achieve and why, rather than what to do and how, believing correctly as it turned out that they could best achieve his requirements without him breathing down their necks whilst they were conducting operations. This was a lesson Slim had learned as a young officer. ‘Choose your subordinates and then decentralise to them.’ The result was an army with commanders able, in one memorable phrase, of being able to ‘shoot a goal when the referee wasn’t looking.’

Third, Slim’s knowledge of his enemy was unparalleled. He fought the Japanese continuously from early 1942, at the start of the retreat, until final and unequivocal victory was achieved over three years later. He regarded a full and comprehensive knowledge of the enemy to be a vital prerequisite for any commander because, as he argued, ‘battle is largely a struggle between the wills of the commanders.’ This was no mere sop to the theory of war: all of Slim’s key moves in India and Burma were made as a direct result of what he knew the enemy would do, and in every major case he was proved right.

Fourth, Slim knew only too well the relationship between the various levels of conflict and was able to master each. In brief, the operational level is that which connects the strategic objectives of government with the tactical employment of forces on the battlefield. So, for troops to be usefully employed on the ground they need to be acting to achieve a strategic objective: it is the general and his staff in the middle who have to translate these plans into action to achieve these grand objectives. The nature of operational art therefore lies in the skill that a commander can bring to the allocation of military resources to meet strategic objectives. Slim in Burma succeeded in understanding the nature and requirements of operational art where many others consistently failed.

Professor Dixon argues that, unusually for a senior commander of his ilk in WW2, Slim was non-ethnocentric. He had no intrinsic prejudices about the virtues of one race over another. Slim, after all, was an officer of the Indian Army, and I have yet to come across any evidence that British regimental officers of the Indian Army regarded their soldiers in any way inferior to themselves. He was commonly known to those who served under him as ‘Uncle Bill’ from the special affinity British troops had to him: the remarkable fact, however, was that at least 87% of his Army of several hundred thousand men recalled him as ‘Cha Cha Slim Sahib’: 14th Army was, after all, very largely Indian, Gurkha and West and East African. I certainly cannot think of any other Indian Army general who had such an impact on British troops. He became, of course, Chief of the Imperial General Staff following Field Marshal Montgomery, in 1948, which securely establishes this feat. On that note, I cannot conceive of ‘Uncle Bernard’ when referring to Field Marshal Montgomery!

The Burma campaign was as much a struggle for mastery of logistics as it was a struggle for mastery on the battlefield, and it was about risk as much as it was about adherence to logistical principles. Slim had an implicit understanding of the constraints placed on warfare by the demands of logistics. Great efforts were made to increase the quantity of supplies to Burma. Railways were extended, roads built and surfaced, sunken ferries refloated and repaired, barges and rafts built for use on the numerous waterways. In this regard Archibald Nye, the VCIGS under Alan Brooke, regarded Slim’s mastery of logistics to be the most significant measure of his greatness as commander of 14 Army in Burma:

‘He never had enough to do what he had to do and this ... is the measure of his greatness.’

The practice of war in Burma by Slim was so startling in its modernity, and unlike any other pattern of warfighting by operational level British commanders in the war. My view of Slim as a commander can be interpreted at two levels. He was, first of all, a great commander and leader. Being a master of strategy, of logistics, of technical proficiency and so on are important in themselves when considering the nature of leadership in war, but by themselves they remain insufficient. Successful military command requires someone who can, through dint of personality and inspirational leadership, wield all of the components of fighting power together so that an extraordinary result transpires. What marks Slim out from the crowd was much more than just his winning of a succession of extraordinary battles. His strength lay in his ability to produce a decisive effect from scratch; to mould thousands of disparate individuals together into a single team with a single goal; to persuade a defeated army that it had the potential to turn the tables on their enemies; to master the complexities of terrain, climate and administrative deficiency so that self-help, resourcefulness and ingenuity could become as much prized as fighting skill. In these individual areas, and more, Slim proved the master. His genius for war was the consequence of his ability to bring together all of these elements to create an extraordinary result, the visible sign of which was the greatest defeat suffered by the Japanese on land during the Second World War.

This is not the whole story. The key factor in Slim’s military success was his espousal of the principles of what we today call ‘manoeuvre warfare’. Victory in Burma in 1945 was achieved by an army that applied, with absolute consistency and devastating effect, a manoeuvrist approach to warfighting. It was a victory not just for the moral over the physical but for the application of doctrine that stressed pre-eminently the need to hit the enemy where he was weakest and then, by the careful, selective and cunning use of force, to remove his will to win. The masterpiece of Allied strategy, as Kimura so rightly acclaimed, was the product of the calculated orchestration of a dynamic, skilful and victorious army; Slim was the maestro who conducted it all. His experience of command in war provides an almost perfect model for the study of manoeuvre warfare and bears out in full Mountbatten’s claim that he was the finest general the Second World War produced.