The Japanese cross into India

By about 22 March 1944 units of the Japanese Fifteenth Army were on Indian territory across the whole width of the Imphal front – from the mountains north-east of Imphal to the Tiddim road in the south. Two weeks earlier Operation U-Go had begun: the 33rd Division had attacked the 17th Indian Division at Tiddim, and on 15 March the 15th and 31st Divisions had crossed the Chindwin. Now their columns were coming down from the mountains deep into Manipur – a princely state under British suzerainty with Imphal as its capital – and towards the Naga Hills and Kohima.

War chronologies place “the crossing of the Indian frontier along the whole Imphal front” under this date. The crossing was not a single event: in the north Japanese columns had entered Manipur as early as around 18–20 March, while in the south most of the fighting was still taking place on the Burmese side of the Chin Hills. In Tokyo the news of the “crossing of the frontier” was announced in a special communiqué of Imperial General Headquarters, issued, according to Japanese accounts, on the night after 23 March at the personal demand of Prime Minister Hideki Tōjō. The date of 22 March is therefore best treated as a conventional one.

Sangshak

The fastest-moving force was the left column of the 31st Division – the main body of the 58th Regiment under Major General Shigesaburō Miyazaki, which had the shortest route to Kohima. Around 18 March it approached Ukhrul, a hill village 40 kilometres north-east of Imphal. A few kilometres to the south stood Brigadier Maxwell Hope-Thompson’s 50th Indian Parachute Brigade – newly arrived, fighting as infantry, without barbed wire or prepared positions. On 19 March the Japanese overran one of its forward companies on Point 7378; only about 20 men of the company were left. Hope-Thompson concentrated the brigade and on 21 March withdrew it to Sangshak, a small hill by the village with a mission church at its northern end. The position was a few hundred metres long, had no water, and lay on rock beneath a thin layer of soil, so the trenches were shallow.

Sangshak actually lay in the sector of the 15th Division, but that division was lagging behind. Miyazaki decided to clear the way himself. On the night of 22/23 March a battalion of the 58th Regiment attacked from the north without artillery support and suffered heavy losses from the defenders’ mountain guns and mortars. On the body of one of the dead Japanese officers maps and orders were found containing the plan of the entire 31st Division. Hope-Thompson sent them through the Japanese lines to Imphal. Over the following days the Japanese brought up artillery, partly on elephants, and fresh battalions; on 25 March a battalion of the 60th Regiment from the 15th Division also attacked from the east. Much of the supplies dropped to the defenders fell on Japanese positions. On the evening of 26 March the brigade was ordered to withdraw and during the night broke out of the encirclement towards Imphal, leaving some of its badly wounded behind.

According to British figures the 50th Brigade lost about 650 men, and the II Battalion of the 58th Regiment alone over 400. Something else mattered more: the battle held Miyazaki up for roughly a week, and the captured documents showed Lieutenant General William Slim that what was advancing on Kohima was not a regiment, as he had assumed until then, but a whole division.

The withdrawal from Tiddim and the Shenam Pass

In the south, Major General David Cowan’s 17th Indian Division had since 14 March been fighting its way north along the Tiddim–Imphal road, more than 200 kilometres long. Lieutenant General Genzō Yanagida’s Japanese 33rd Division had set up blocks on it: the 214th Regiment on the Tuitum ridge and the 215th Regiment by the depots at Milestone 109. The 48th Brigade broke the block at Tuitum as early as 15 March, and the Japanese suffered heavy losses there. The depot at Milestone 109 fell on 18 March, but on 25 March Indian troops retook it and carried away most of the food, ammunition and vehicles. To help Cowan, Lieutenant General Geoffry Scoones sent two brigades of the 23rd Division from Imphal – most of IV Corps’ reserve. On 26 March the rearguard of the 17th Division crossed the bridge over the Manipur river and blew it up behind them. The division escaped the encirclement with its wounded and its equipment, and according to Japanese accounts Yanagida, to the fury of the army commander, Renya Mutaguchi, had already concluded that its destruction was impossible and did not press as hard as Mutaguchi demanded. On the 33rd Division’s left flank the Subhas Regiment of the Indian National Army reached the edge of the Chin Hills at the end of March.

At Tamu, Major General Douglas Gracey’s 20th Indian Division held out longer. On 20 March six M3 Lee tanks of the 3rd Carabiniers destroyed six Japanese Type 95 light tanks leading the attack of the Yamamoto Force. Gracey did not want to fall back, but on 25 March he had to give up part of his division to the corps reserve and withdrew the rest to the Shenam Pass, where the Tamu–Imphal road crossed a range of hills. The great depot at Moreh was burned.

The airlift and the threat to Kohima

The scale of the threat was grasped belatedly at Imphal and at Fourteenth Army headquarters in Comilla, but the response was swift. On his own responsibility Admiral Louis Mountbatten took several dozen transport aircraft off the Himalayan supply route to China, among them 20 Curtiss C-46 Commandos. From 19 March they were used to fly the 5th Indian Division from the Arakan to the central front – the same division that had taken Maungdaw in January and repelled the Japanese Ha-Go offensive in February. According to British accounts the whole division, with its artillery, jeeps and mules, was flown in within eleven days. Two of its brigades reinforced Imphal; the third, the 161st Brigade, was sent to Dimapur.

Dimapur, for its part, was the weakest point of the whole front. It lay on the railway to Assam and held depots stretching for a dozen or so kilometres, but had almost no defences. Slim asked General George Giffard for reinforcements; the British 2nd Division and the headquarters of Lieutenant General Montagu Stopford’s XXXIII Corps set off by rail from the interior of India, and the 23rd Chindit Brigade, detached from the forces of Operation Thursday, was sent to Jorhat on the Brahmaputra to threaten the Japanese flank. At the end of March – on 28 or 29 March, according to different accounts – the 60th Regiment of the Japanese 15th Division cut the Imphal–Kohima road a dozen or so kilometres north of Imphal. From then on IV Corps was cut off by land and supplied only by air.

The “Japanese retreat” of 28 March

Some chronologies state under 28 March that “Japanese forces are withdrawing in Burma”. On the Imphal front the exact opposite was true: at the end of March the Japanese were attacking, closing in on Imphal from the north and advancing on Kohima, and their retreat did not begin until July. They were, however, falling back on other sectors. In the Arakan, after the failure of the Ha-Go offensive, called off on 26 February, the British XV Corps took Buthidaung and the fortifications at Razabil in March. In the north the Japanese 18th Division was retreating down the Mogaung valley before the Chinese and the American “Merrill’s Marauders” of General Joseph Stilwell, who had been fighting in the Hukawng valley since December and at the end of March approached Shaduzup. The entry can thus be applied to those fronts, but not to Imphal.

What the end of March brought

In the last ten days of March it was settled that the Japanese would not destroy IV Corps’ forward divisions in the mountains, as their plan had envisaged. The 17th and 20th Divisions withdrew to the plain with most of their equipment, and the 5th Division was flown in from the Arakan. Imphal, surrounded on the north, east and south, became a great fortress supplied from the air. The delay at Sangshak gave the British time to reinforce Kohima, though not much: when the 31st Division reached the town at the beginning of April, the garrison numbered, according to British accounts, only about 1,500 men fit to fight. The siege of Kohima, the fighting for the ridge with the tennis court by the Deputy Commissioner’s bungalow and the battle of Imphal lasted until June. In July Mutaguchi called off the operation, and the retreat through the mountains in the monsoon turned into one of the greatest disasters of the Japanese army.