The entire Assam Line of Communications was a complex system to overcome the logistical
crisis created when the Japanese cut off the Burma Road.
Here are the key components:
Brahmaputra River barge route - Moved supplies from Calcutta upriver to Assam
Bengal and Assam Railway - Connecting Calcutta to Ledo/Assam
"The Hump" airlift - Air transport from airfields in Assam across the Himalayas to China (primarily Kunming)
Ledo Road (later Stilwell Road) - A new land route from Ledo, Assam through northern Burma to connect with the old Burma Road.
Construction began in December 1942. Its first section (Ledo to Shingbwiyang) was completed around December 1943.
The connection to the old Burma Road near Mong-Yu was achieved in January 1945
:: Area under Japanese control since June 1942 ::
By June 1942, Japanese forces controlled all of Burma (Myanmar) following their December 1941 invasion, the capture of Rangoon
in March 1942, and Allied resistance collapse by May 1942.
The occupation included expulsion of British and Chinese forces, though Allied guerrilla activity (notably
Chindits) persisted throughout.
Japan also occupied the Andaman and Nicobar Islands in the Bay of Bengal in March 1942, seizing them from British control, later
nominally transferring them to the Provisional Government of Free India (Azad Hind) in late 1943, while maintaining military control.
Japanese-occupied territory reached near the Burma-India border, with brief incursions into northeastern India, but no full control of
Indian territory as of June 1942. Their 1944 Imphal and Kohima offensives into India ended in defeat.
In August 1943, the Japanese established the State of Burma as a nominally independent puppet regime under Dr. Ba Maw, with the title
of Naingandaw Adipadi (Head of State). However, real power remained with the Japanese military, particularly the Burma Area Army.
Conditions under occupation were often brutal, with forced labor used for military logistics projects such as the infamous Burma-Thailand
Railway (also known as the Death Railway), which caused the deaths of tens of thousands of Asian laborers and Allied POWs.
The Japanese also supported the creation of the Indian National Army (INA) under Subhas Chandra Bose, formed
from Indian prisoners of war and civilian volunteers from Southeast Asia. After mid-1943, the INA's
headquarters moved to Rangoon, with training and recruitment throughout
Japanese-occupied territories (Malaya, Singapore, Indochina), but Burma became the main base of operations. The INA participated in the 1944
U-Go offensive, notably in the battles of Imphal and Kohima, as mentioned above.
As of mid-1942, Japanese influence extended across most of Southeast Asia, including:
Thailand (ally functioning as client state)
French Indochina (Vietnam, Laos, Cambodia), under Vichy French administration but effectively controlled by Japan
Malaya and Singapore, both captured by February 1942
The Dutch East Indies (modern Indonesia), mostly under Japanese control by March 1942
The Philippines, largely occupied after the fall of Bataan (April 1942) and Corregidor (May 1942)
Large portions of New Guinea, the Solomon Islands, and Micronesia
Manchuria, Korea, and Taiwan (under Japanese rule prior to WWII)
By 1943-1944, Japan's control weakened due to overstretched supply lines and mounting resistance from Allied forces and local guerrillas —
such as the Karen and Kachin fighters in Burma, and Viet Minh in Indochina.
Control along the India-Burma frontier was particularly contested.
:: The "Hump" Airlift Over the Himalayas to China ::
"The Hump" was the treacherous aerial supply route over the eastern Himalayas connecting Allied airbases in Assam, India , to
Kunming and other destinations in Yunnan Province, China. Launched April 1942 after Japan severed the Burma Road, it was the
first sustained, long-range, around-the-clock, all-weather military airlift in history.
Initially called "India-China Ferry," the operation began under the Tenth Air Force and later transferred to Air Transport
Command (ATC), specifically its India-China Wing (renamed the India-China Division in 1944). Flights officially operated
July 1942 to November 1945.
Flying "The Hump" required altitudes of 15,000-16,000 feet over extreme terrain with unpredictable weather, including
turbulence, ice, monsoons, and hurricane-force winds. Pilots faced limited navigation aids, primitive maps, and
initially, Japanese interception threats. Early airfields were rudimentary with frequent mechanical failures.
Under Major General William H. Tunner (late 1943), the operation expanded dramatically.
By July 1945, monthly deliveries reached 71,000+ tons. Total airlift: approx. 650,000 tons of supplies supporting
Chinese Nationalist forces and General Claire Chennault’s Fourteenth Air Force.
The operation cost over 500 aircraft lost and 1,200+ personnel killed or missing. Despite this heavy toll, the airlift
kept China in the war, diverted Japanese resources, and established a precedent for future strategic airlifts like
the Berlin Airlift (1948-1949).
:: Air Transport Command (ATC) airfields in Assam ::
The ATC operated numerous Assam airfields for "The Hump" airlift after Japan closed the Burma Road.
Chabua served as sector headquarters and main logistics point, especially critical during monsoons
when other fields became unusable. Other key bases included Mohanbari, Sookerating, Jorhat, Dinjan, Tinsukia,
and Ledo, with Ledo supporting southern shuttle routes after Myitkyina's capture.
Shingbwiyang (Burma) marked the initial Ledo Road terminus and had an airstrip but wasn't a regular ATC cargo hub.
The Hump airlift succeeded strategically through this network of Assam airfields serving as staging points for
one of the war's most dangerous supply routes.
Credits
Courtesy of the United States Military Academy Department of History.
