Our next campaign began on Sunday the 13th of May 1944 and it revolved around the Air Battle for Imphal.
This campaign had a different structure from our normal Sunday missions. Instead of flying with just one squadron and type we flew a different aircraft and mission each week.
All the missions were historic and completed in chronological order. We got to experience a flavour of the whole air battle from air defence in a Spitfire VIII to dive bombing in a Vultee Vengeance.
In 1942, the Japanese Army had driven the British, Indian and Chinese troops out of Burma. The retreat of the Allied Burma Corps stopped at Imphal, which lay in a plain on one of the few practicable routes through the ranges of jungle-covered hills which formed the border between Burma and India. Over the following year, the Allied troops slowly improved their training, equipment and morale, and increased the capacity of the lines of communication to the Assam front. At the start of 1944, the Allies were poised to invade Burma on several fronts. Imphal was built up to be a substantial logistic base, with airfields, encampments and supply dumps.
Origins of the Japanese Plan: In 1943 a new Japanese headquarters, Burma Area Army, was created under Lieutenant-General Masakasu. His natural instinct was to mount an offensive against Imphal. He may also have been goaded by the first Chindit expedition launched by the British under Orde Wingate early in 1943. Wingate's troops had apparently easily traversed terrain which Mutaguchi had earlier claimed would be impassable to the Japanese 18th Division which he commanded at the time. The Allies had widely publicised the successful aspects of Wingate's expedition while concealing their losses to disease and exhaustion, possibly misleading Mutaguchi and some of his staff as to the difficulties they would later face.
A spoiling attack to disrupt Allied plans was standard Japanese practice. Mutaguchi had larger ambitions. He planned to exploit the capture of Imphal by advancing to the Brahmaputra River valley, thereby cutting the Allied supply lines to their front in northern Burma, and to the airfields supplying the Nationalist Chinese under Chiang Kai-shek over "The Hump".
The Japanese Plan: Imphal was held by the Indian IV Corps. Because the Allies were planning to take the offensive themselves, its units were thrown forward almost to the Chindwin River and widely separated. Mutaguchi intended to cut off and destroy the Allied units in their forward positions and then capture Imphal.
All Mutaguchi's divisional commanders disagreed with the plan to some extent. Their main reservations concerned supply. Mutaguchi had assumed success within three weeks, but adequate supplies after that period could be obtained only if the Japanese captured Allied supply dumps, as the torrential rains that the spring season would inevitably bring would make supply routes from the east impossible to traverse. Gambles such as Mutaguchi was making had worked in the past, but could no longer be relied upon to work, given nearly total Allied air superiority in the area and the improvement in morale and training of British and Indian troops.
There were other weaknesses in the plan which were to be revealed as the campaign progressed. The Japanese assumed that the British would be unable to use tanks on the steep jungle-covered hills around Imphal. For the sake of ease of movement and supply, the Japanese were leaving behind most of their field artillery, their chief anti-tank weapon. As a result, the Japanese troops would have very little protection against tanks if these were in fact used against them.
Prelude to the Operation: In late February, a local Japanese counter-attack was launched against Indian XV Corps in Arakan. The attack failed when Allied aircraft parachuted supplies to cut-off troops, allowing them to stand firm while the Japanese ran out of supplies. The engagement became known to the British as the Battle of the Admin Box. From this point onwards, the Allies were to place increasing faith and reliance on their transport aircraft. Even as the Japanese prepared to launch their attack, on 5 March 1944 the Allies launched the airborne phase of the second Chindit expedition.
The Second Chinjit Raid: The Chindits were the brainchild of British Brigadier Orde Charles Wingate. The 77th Indian Infantry Brigade, otherwise known as the Chindits, was gradually formed around Jhansi during the summer of 1942. Half of the Chindits were British infantry soldiers from the 13th Battalion King's Liverpool Regiment, and men from the Bush Warfare School in Burma who were formed into 142 Commando Company. The other portion of the force was made up of the 3/2nd Gurkha Rifles and 2nd Burma Rifles. Wingate trained them as Long-Range Penetration units that were to be supplied through air. Usual armament was rifles, Thompson submachine guns, pistols, mortars, grenades and knives. A mule transport company carried their supplies. RAF sections were attached to each column for the purpose of air coordination.
The methods of the Chindits in 1944 differed from those of 1943. Wingate had decided on a method of creating fortified bases behind the Japanese lines which would then send out raiding columns over short distances. This change was in part forced upon him by improved Japanese patrols along the frontier making a repeat of the successful infiltration in 1943 unlikely. The lavish air support provided by the 1st Air Commando Group allowed also him this option.
Operation Thursday: Three landing zones, codenamed Piccadilly, Broadway and Chowringhee were selected. Calvert's 77th Brigade prepared to fly by glider into Piccadilly on the night of March 5. A last minute reconnaissance revealed Piccadilly to be covered with logs making landing impossible and the gliders were diverted to Broadway. Broadway was a worse landing ground and there were many casualties in crash landings, but Calvert's men were just able to make the strip fit to take transport aircraft. Chindit gliders landed on Chowringhee the next day.
Over the next week, 600 sorties transferred 9000 men to the landing zones. Chowringhee was abandoned once the fly-in was completed, but Broadway was held with a garrison which included field artillery, anti-aircraft guns and even Spitfire fighters for a brief period. Fergusson's brigade set up another base named Aberdeen north of Indaw, into which 14th Brigade was flown. Calvert's brigade established yet another, named White City at Mawlu, astride the main railway and road leading to the Japanese northern front. 111 Brigade set up ambushes and roadblocks south of Indaw before moving west to Pinlebu.
Ferocious jungle fighting ensued around Broadway and White City. At times, British and Japanese troops were in close combat, bayonets and kukris against katanas. On March 27, after days of aircraft attack, Japanese attacked Broadway for several nights before the attack was repulsed with flown-in artillery and the aid of Kachin irregulars locally recruited.
On March 24, Wingate flew to Imphal to confer with air force commanders. Returning, his aircraft is believed to have flown into a thunderstorm, and crashed in the jungle-covered mountains. All aboard were killed. Back to Top
Indian IV Corps in Imphal was commanded by Lieutenant-General Geoffrey Scoones, and was in turn part of the British Fourteenth Army under Lieutenant-General William Slim. When they received intelligence that a major Japanese offensive was impending, Slim and Scoones planned to withdraw into the Imphal plain and force the Japanese to fight with their logistics stretched beyond the limit. However, they misjudged the date on which the Japanese were to attack, and the strength they would use against some objectives. The Japanese launched their troops across the Chindwin River on 8 March 1944. Scoones only gave his forward divisions orders to withdraw to Imphal on 13 March.
The Indian 20th Division under Major-General Douglas Gracey withdrew without difficulty, mainly because two of Yamamoto's battalions from the Japanese 15th Division were delayed at Indaw in northern Burma by the Chindits and were unable to intervene.
The Indian 17th Division under Major-General Cowan was cut off by the Japanese 33rd Division. The Japanese 215 Regiment captured a supply dump at Milestone 109, twenty miles behind Cowan's leading outposts. The Japanese 214 Regiment seized Tongzang and a ridge named Tuitum Saddle across the only road, a few miles behind the Indian 17th Division's position.
At Tuitum Saddle, 214 Regiment were unable to dig in properly before they were hit by the Indian 48th Brigade on 18 March. The Japanese suffered heavy casualties and were forced away from the road. Fighting around Milestone 109 was even more severe, but Cowan had taken steps to secure the most vulnerable point in the rear of his division, the bridge over the Manipur River. 17th Division crossed safely, demolishing the bridge behind them, and recovered the depot on 25 March. They were forced to abandon large amounts of supplies, but removed most of the vehicles, food and ammunition. The Japanese were left only such items as clothing and blankets.
Scoones had nevertheless been forced to send the bulk of his only reserve, Indian 23rd Infantry Division under Major-General Ouvry Roberts, to the aid of 17th Division. The two divisions, now supplied by parachute drops from Allied aircraft, made their way back to the Imphal plain, which they reached on 4 April.
Meanwhile, Imphal had been left vulnerable to the Japanese 15th Division. The only force left covering the base, Indian 50 Parachute Brigade, was roughly handled at Sangshak by a regiment from the Japanese 31st Division on its way to Kohima. The 31st Division had also blocked the main road south of Kohima by the start of April, cutting off IV Corps. However, an earlier diversionary attack launched by Japanese 55th Division in Arakan had already failed. Slim was able to move the battle-hardened Indian 5th Infantry Division, including all its artillery and transport, by air from Arakan to the Central Front. The move was completed in only eleven days. Two of its brigades went to Imphal, and their leading troops were in action on 3 April.
Stalemate: From the beginning of April, the Japanese attacked the Imphal plain from several directions. 33rd Division attacked from the south at Bishenpur, where they cut a secondary track from Silchar into the plain. Yanagida, its commander, was already pessimistic and depressed by the failure to trap the Indian 17th Division. He had also been rattled by a garbled radio message which suggested that one of his regiments had been destroyed at Milestone 109. He therefore advanced cautiously. By doing so, he may have lost a chance to gain success while the Indian 17th Infantry Division was resting after its retreat and Bishenpur was held only by Indian 32 Brigade (from 20th Division). Mutaguchi removed him from command.
Yamamoto Force attacked the Shenam Saddle on the main road from Tamu into Imphal. The Shenam Saddle was ideal defensive terrain. Despite using heavy artillery and tanks, Yamamoto could not break through Indian 20th Division's well-sited defences. Detachments from two brigades of the Indian National Army fought on the Japanese side in this sector. The initial enthusiasm of most INA soldiers soon waned, and they deserted and straggled in increasing numbers. 15th Division encircled Imphal from the north. Its 60 Regiment captured a British supply dump at Kangpokpi (also known as "Mission" from a church there) on the main Imphal-Dimapur road, but once again, the depot had already been emptied of food and ammunition. 51 Regiment seized the vital Nunshigum Ridge, which overlooked the main airstrip at Imphal. This was a major threat to IV Corps, and on 13 April the Indian 5th Division counter-attacked, supported by massed artillery and the M3 Lee tanks of the 3rd Carabiniers. The Japanese regiment had no anti-tank weapons, and their troops were driven from the ridge with heavy casualties.
Allied Counter-Attacks: By 1st May, all Japanese attacks had come to a halt. Slim and Scoones now began a counter-offensive against the Japanese 15th Division. This division was the weakest of the Japanese formations, and success against it would break the siege. Progress was slow. The monsoon had broken, making movement very difficult. Also, IV Corps was suffering some shortages. Although rations and reinforcements were delivered to Imphal by air, artillery ammunition was by now rationed. The steep ridges held by the Japanese were almost impregnable.
However, the Japanese were at the end of their endurance. Neither their 31st Division at Kohima, nor 15th Division, had received adequate supplies since the offensive began, and their troops were starving. This allowed Indian XXXIII Corps to drive the Japanese from Kohima at the end of May, and advance south. The troops of Japanese 15th Division were forced to abandon their defensive positions to forage for supplies in local villages. The leading troops of IV Corps and XXXIII Corps met at Milestone 109 on the Dimapur-Imphal road on 22 June, and the siege was raised. Back to Top
By mid-1944, the Allied air forces controlled the skies over Burma. The last major effort by the Japanese Army Air Force had been over the Arakan and Imphal in February and March, when they had suffered severe losses. IV Corps enjoyed close air support from fighter-bombers and dive bombers. Allied fighter bombers and medium bombers shot up and bombed enemy concentrations, supply dumps, transport, roads and bridges all the way to the Chindwin river. The monsoon in no way diminished their activity. The Third Tactical Air Force (TAF) increased their sortie rate to 24,000 sorties during the worst four months of the monsoon, nearly six times the figure of the previous year's record.
The Allies could fly men, equipment and supplies into the airstrips at Imphal so although cut off by land, the town was not without a lifeline. Allied aircraft could also parachute ammunition, rations and even drinking water to surrounded units.
RAF Third Tactical Air Force: The RAF Third Tactical Air Force (Third TAF), which was formed in south Asia in December 1943, was one of three tactical air forces formed by the Royal Air Force during World War II. Third TAF was formed shortly after the establishment of South East Asia Command to provide close air support to the Fourteenth Army. It was first formed on 19 December 1943 designated the Tactical Air Force (Burma) and renamed as the Third TAF on 28 December 1943. Along with parts of the USAAF Tenth Air Force, it was subordinate to Joint Allied Eastern Air Command which was also formed in December 1943.
As the Air Force was formed, it was felt that at last British forces could go over to the offensive against the Japanese in the Burma Campaign. A start was made towards establishing a general offensive in Arakan in early 1943, but this was forestalled by a Japanese offensive. The Japanese were decisively beaten, but they shifted the focus of their attack to central Burma. Third TAF gave sterling service to Fourteenth Army during the Battle of Kohima and the Battle of Imphal, strafing and bombing the besieging Japanese troops, often at very low level.
After the defeat of the Japanese by Indian IV and XXXIII Corps in Assam, the monsoon intervened before many counterattacks could take place. After the enforced period of reduced operations, the Third TAF supported the advance of Fourteenth Army against the Japanese forces. However, command arrangement changes at the end of 1944 cutting short the life of the Third TAF. It was redesignated HQ RAF Bengal and Burma on 4 December 1944.
USAAF Air Commando Group: The British were substantially assisted in supply and Chindit operation by the US Army Air Force in Burma. Substantial numbers of C47's and gliders were used used during Operation Thursday and in the resupply of Imphal. US P51's and P38's also carried out strikes against Janaese airfields and communications as well as supporting their own drive south from the Chinese border at Ledo. Back to Top