The retreat from Kohima

On 31 May 1944 the commander of the Japanese 31st Division, Lieutenant General Kōtoku Satō, began withdrawing his units from Kohima in Assam. His men had been starving for weeks, the promised supplies had not arrived, and the monsoon rains had turned the mountain tracks to mud. Satō acted on his own responsibility, against the explicit orders of the commander of the Fifteenth Army, Lieutenant General Renya Mutaguchi. In the Japanese army this was unprecedented: a divisional commander had broken off the fighting on his own and withdrawn without his superior’s consent.

War chronologies record under this date that the Japanese withdrew from Imphal with heavy losses and that their invasion of India was over. This is a simplification. On 31 May the retreat began only from Kohima, and only by one division. At Imphal the Fifteenth Army’s two other divisions fought on throughout June, and Mutaguchi called off Operation U-Go only on 3 July. The departure of the 31st Division nevertheless decided the outcome of the battle: it opened the road south from Kohima to besieged Imphal for the British.

The last bunkers on the ridge

At the beginning of May the Japanese still held most of the Kohima ridge. The garrison, which had been under siege there since 6 April, had been relieved on 18 April, but the 31st Division’s left column under Major General Shigesaburō Miyazaki was sitting in deeply dug bunkers on Kuki Picquet, on FSD, DIS and Jail Hill, and around the ruined bungalow of the Deputy Commissioner. Divisional headquarters and Colonel Shiraishi’s centre column, four battalions in all, held Naga Village north of the ridge; to the south the Japanese held GPT Ridge and the wooded Aradura Spur.

The British 2nd Division under Major General John Grover, part of Lieutenant General Montagu Stopford’s XXXIII Corps, first tried to outflank these positions on both sides. On 4 May the 5th Brigade broke into the edge of Naga Village, but a counter-attack drove it out again. The same day the 4th Brigade, after a long march across the slopes of the Pulebadze massif, surprised the Japanese in a downpour and took part of GPT Ridge, but could not seize all of it; over the following days two successive brigade commanders were killed. Terrain and weather stalled both outflanking moves, so from 4 May the 2nd Division attacked mainly along the ridge itself, supported by the Indian 33rd Brigade of the 7th Division, which was just then being brought up from the Arakan.

Progress was slow and costly. Fire from Japanese positions on the reverse slope of GPT Ridge repeatedly took in the flank the men assaulting Jail Hill. Only on 11 May, under a smokescreen that blinded the Japanese machine-gunners, did British and Indian troops take Jail Hill, Kuki Picquet, FSD and DIS. The last point of resistance on the ridge was the tennis court and the garden above the Deputy Commissioner’s bungalow, where since April the two sides’ trenches had been separated by a dozen or so metres. On 13 May, after several failed attempts, sappers bulldozed a track up to the higher terrace, along which an M3 Lee tank was hauled. The tank drove onto the tennis court and destroyed the Japanese bunkers at close range, and the 2nd Battalion, the Dorsetshire Regiment took the slope on which the bungalow stood. The Kohima ridge was clear. The battlefield had become a wasteland teeming with flies and rats and full of half-buried corpses; British historians describe the conditions in which the Japanese soldiers lived and fought there as unimaginable.

Naga Village and the Aradura Spur

Losing the ridge did not yet mean the end of the fighting for Kohima. The Japanese still held Naga Village, Treasury Hill and Church Knoll to the north and the Aradura Spur to the south, and so continued to block the road from Dimapur to Imphal. The whole of Major General Frank Messervy’s Indian 7th Division now entered the battle; its headquarters and 114th Brigade arrived on 12 May, and together with the 161st Brigade it was to retake Naga Village from the north. The exhausted brigades of the 2nd Division were relieved for a time by the independent Indian 268th Brigade.

On 16 May the Allies attacked again, but the Japanese continued to resist fiercely. An attack on the hill at Naga Village on the night of 24/25 May gained not a metre of ground, and an assault on both ends of the Aradura Spur on the night of 28/29 May was repulsed even more decisively. Repeated failures, fatigue and the draining mountain climate told on the morale of the British 2nd Division. The monsoon, which arrived at the beginning of May, turned the slopes to mud, and every attack needed porters and mules to carry ammunition and the wounded.

The Japanese, however, were defending themselves with the last of their strength, and their units were dwindling day by day. Who would hold out longer was no longer being decided by further assaults, but by supply.

The 31st Division starves

The 31st Division had crossed the Chindwin in mid-March with food for about three weeks. Mutaguchi assumed that by then the Japanese would have captured British depots and that the army’s rear services would supply the rest. Before the operation Satō had obtained from the Fifteenth Army staff a promise of supplies – according to Japanese accounts, about 10 tons of food and ammunition a day. In practice these supplies never came. Two attempts to bring them up in captured jeeps delivered mainly artillery and anti-tank ammunition, not rice. A large rice store captured at Naga Village in early April was destroyed by British aircraft. The British 23rd Long Range Penetration Brigade – one of the Chindit brigades commanded until his death in March by Orde Wingate – operated in the division’s rear, cutting its supply routes and preventing it from gathering food in the Naga villages east of Kohima. The surrounding Naga villages were increasingly hostile to the Japanese, and many Nagas helped the British as porters, guides and scouts.

By mid-May Satō’s men were starving. Rations had fallen to a handful of rice and whatever could be found in the forest; malaria, dysentery and beriberi were spreading. For weeks Satō had been sending signals to Fifteenth Army headquarters demanding supplies and, in time, calling for the whole operation to be abandoned. Their tone grew ever sharper; copies also went to the headquarters of the Burma Area Army under Lieutenant General Masakazu Kawabe, who drew Mutaguchi’s attention to their insulting language. For two months the army staff sent no one to the division to see the situation on the spot. When a supply officer and an intelligence officer finally arrived on 18 May, Satō – according to Japanese accounts – greeted them with the cry that the enemy was not the British but the Fifteenth Army.

On top of this came conflicting orders. As early as April Mutaguchi, whose attack on Imphal had stalled, wanted Satō to give up part of his force for a thrust on Imphal from the north, even though the 31st Division was barely holding its positions at Kohima. Satō refused, and from then on regarded the army’s orders as divorced from reality. He believed the division was being squandered without a plan and without supplies, and that headquarters was doing nothing to get food through to it.

Satō’s decision

Satō had long distrusted Mutaguchi. In the 1930s the two had belonged to rival factions in the army, and Satō believed that Mutaguchi had already harmed his career then. Before Operation U-Go he had publicly declared that his division would get as far as Dimapur, but he had also told his officers that they might all die of starvation. At Kohima both predictions collided with reality: on one side stood the order to hold the positions to the last, on the other a division falling apart from exhaustion.

On 25 May Satō informed Fifteenth Army headquarters that unless he received supplies he would withdraw on 1 June. Mutaguchi replied with an order to hold the positions, couched in threatening terms. Satō judged it impossible to carry out and insulting, and the pressure an attempt at intimidation. According to Japanese accounts, in his last signal before leaving he wrote that after sixty days of fighting, “to the limit of human endurance”, the division’s “swords are broken and its arrows spent”. At the same time he was sending signals to Burma Area Army headquarters in which he called his superiors’ orders “mindless” and the Fifteenth Army staff incompetent, and suggested that it was the state of mind of the army command that needed a medical examination.

On 31 May the 31st Division abandoned Naga Village and its positions north of the road. According to Japanese accounts the main body set off east on 1 June towards Ukhrul, where the Fifteenth Army promised to gather supplies. On the road to Imphal Satō left Miyazaki’s exhausted detachment – according to Japanese sources only about 750 men – as a rearguard, tasked with delaying the pursuit. To avoid a collapse of the whole front and an open scandal, Mutaguchi on 2 June sanctioned the retreat after the event, while demanding that once it had replenished its supplies the division return to the attack on Imphal. Satō did not carry out this order.

For the British XXXIII Corps the departure of the 31st Division was the breakthrough. The abandonment of Naga Village made it possible to outflank Miyazaki’s positions on the Aradura Spur, and at the beginning of June the 2nd Division set off south down the road towards Imphal, while the Indian 7th Division advanced through the hills east of the road. The battle of Kohima, which since 4 April had cost the British and Indians more than 4,000 killed, wounded and missing and the Japanese at least 5,700 battle casualties, had been decided.

Imphal in May

At Imphal hard fighting was still going on in May. According to British accounts, by 1 May every Japanese attack on the plain had been halted, and Lieutenant General Geoffry Scoones’s IV Corps had gone over to the counter-offensive. It made slow progress: the Japanese 15th Division defended the steep ridges north of Imphal, such as the Mapao Spur, from reverse-slope positions that the artillery could not reach. To the east the Indian 23rd Division took over the defence of the Shenam Pass on the road from Tamu, where since April a detachment under Major General Tsunoru Yamamoto had been attacking with tanks and heavy artillery.

The bloodiest fighting was in the south, near Bishenpur, where the Japanese 33rd Division had come within a dozen or so kilometres of Imphal. In the first half of May there were battles for the village of Potsangbam, in which the British lost 12 tanks. Major General David Cowan’s Indian 17th Division tried to encircle the enemy: on 18 May Gurkhas of the 48th Brigade cut the road in the Japanese rear, but could not link up with the rest of the division and had to fight their way back, taking heavy losses. At the same time the Japanese broke in between the Indian positions and on 20 May seized hills near the headquarters of the 17th Division; over the following week their cut-off groups were wiped out. Mutaguchi, angered by the caution of Lieutenant General Genzō Yanagida, removed him, and on 22 May Lieutenant General Nobuo Tanaka took command of the 33rd Division and ordered attacks to be renewed until the battalions were destroyed.

Senior Japanese commanders were beginning to understand that the operation would fail. On 25 May Lieutenant General Kawabe set out from Rangoon for the front to see the situation for himself, but the men he spoke to concealed the scale of the losses from him. Neither he nor Mutaguchi was willing to take responsibility for ordering a retreat: when they met on 6 June, according to accounts, both understood that success was impossible, but neither said so openly. On the Allied side Admiral Louis Mountbatten, Supreme Allied Commander of South East Asia Command, had already in mid-March, at a critical moment of the battle, diverted on his own responsibility some of the transport aircraft from the airlift to China for use at the front. Throughout May, despite the rains, besieged Imphal received food, ammunition and reinforcements by air, although rations and artillery ammunition had to be husbanded.

What ended on 31 May

The claim that on 31 May the Japanese withdrew from Imphal and that their invasion of India was over runs a month ahead of events. That day only the 31st Division at Kohima began to retreat – and against orders at that. At Imphal the Japanese 15th Division held out north of the town until the second half of June, and the 33rd Division, reinforced by a regiment of the 53rd Division and by tanks, was still renewing its attacks near Bishenpur in June. Mutaguchi was still planning new offensives. Operation U-Go was formally called off only on 3 July, and only then did the whole Fifteenth Army begin to fall back towards the Chindwin. It is true, however, that by the end of May defeat was already certain – and that Satō’s decision sealed it.

Place in the war

The departure of the 31st Division opened the road to Imphal. Miyazaki’s rearguard delayed the pursuit for nearly three weeks, but on 22 June the leading troops of the British 2nd Division met the Indian 5th Division, coming from the direction of the town, at Milestone 109, about 16 kilometres north of Imphal. The siege of Imphal was over. The 31st Division’s retreat proved no less gruelling than the fighting: at Ukhrul, which it reached around 20 June, there was no food, and the small supply convoy that arrived a few days later at Humine lasted only a few days. The withdrawal of soldiers of the Japanese 15th Division, who were leaving their positions in search of food out of hunger, also exposed the Japanese 60th Regiment on the Imphal road; caught between two fires, the regiment lost most of its strength in the battle.

Satō was relieved of his command at the beginning of July. Instead of committing suicide, as Mutaguchi reportedly suggested, he demanded a court martial, at which he intended to accuse the Fifteenth Army command. No trial took place: the Burma Area Army preferred to hush the matter up by sending him for psychiatric examination, and in November it placed him on the reserve list and immediately recalled him to service far from Burma. His retreat is still judged in different ways – some see it as an act of courage that saved the lives of thousands of soldiers, others point out that he left his rearguard and neighbouring units to their fate without warning them of his departure.

From 3 July the whole Fifteenth Army retreated towards the Chindwin at the height of the monsoon. Units, often broken up into loose groups, abandoned their artillery, vehicles and wounded, and men died of hunger, malaria and dysentery along the tracks that came to be called “the road of white bones”. According to the most frequently cited British tallies, the Fifteenth Army lost about 55,000 men, including about 13,400 killed in action; many historians estimate that, counting those who died of starvation and disease, some 30,000 Japanese died in all. British and Indian losses at Imphal and Kohima together came to nearly 17,000 killed, wounded and missing. It was the heaviest defeat the Japanese army had yet suffered on land.

The Japanese invasion of India, which had begun in March with the crossing of the border in Manipur, thus ended not on 31 May but at the beginning of July – yet its fate was decided at Kohima in the last days of May. For Lieutenant General William Slim’s Fourteenth Army it was the turning point of the war in Burma. The shattered Fifteenth Army could no longer hold the line of the Chindwin, and in the following months it was the British who went over to the offensive, which in 1945 took them to Mandalay and Rangoon.