Piercing the Fog - Air Force Historical Studies Office

Piercing the Fog
Africa. Interception and decoding of Japanese low-level radio messages played
a part in determining the AAF’s planning and tactics in the CBI from as early
as May 1942. At that time, the Americans learned of Japanese plans to move air
units north from Malaya and the NEI. They launched attacks on airfields in
Japanese territory. On October 25,1942, Chennault’s B-25s raided Hong Kong
in one of the heaviest strikes that the CATF had yet made. The MAGIC
Diplomatic Summary in Washington had reported ample Japanese shipping in
the harbor, and such information could have been sent to Chennault via the
United States’ military mission in China. An equally likely source was the
Chinese military. The precise origin of information was almost irrelevant,
because Japanese targets in Hong Kong, Canton, and Hanoi, French Indochina,
were plentiful. Hanoi had been the target for B-25s and P-40~ on September 25,
when CATF intelligence estimates warned of substantial Japanese fighter
defenses. On that attack, Chennault’s operations planners sent along extra
fighters for protection. The precaution proved wise when ten Japanese
interceptors had to be driven off; the Americans suffered no losses that day.’
While carrying the aerial campaign against Japanese shipping and airfields
in southeastern China and French Indochina, Chennault also pursued the
primary mission assigned him: defense of the aerial route from Assam, India,
to Kunming, China. Acting under instructions from Tenth Air Force, Chennault’s
air reconnaissance crews photographed and observed Japanese airfields
in northern Burma. That information, supplemented by the RAF in India,
allowed Chennault and Colonel Cooper to assess Japanese regional air
capabilities late in 1942. Based on these studies, Chennault and Bissell both
believed the Japanese threat to be increasingly dangerous, with Japan able to
operate as many as 350 aircraft in the area. Bissell reported his understanding
of the growing threat to Stilwell, who was engaged in trying to obtain British
approval and support for the training of 45,000Chinese troops in India. Stilwell
hoped to use these Chinese divisions for an offensive in conjunction with
British Indian forces beginning in February 1943. Bissell warned Stilwell on
October 8, 1942, that the AAF’s air reconnaissance fleet was too small in size
and too limited in range to be able to prevent a surprise should the Japanese
decide to move forcefully into the area. Despite the problems, the airmen kept
watch on Japanese troop increases west of the Salween River in November.’
To plan, execute, and evaluate these and other early missions in the CBI,
American air commanders relied on a variety of intelligence sources. Among
them, the most important during the first year of the war were British. The
official relationship between American and British airmen in the India-Burma
Campaign differed from the one that existed in North Africa and the United
Kingdom. No Allied air command such as NAAF existed until the creation of
EAC in December 1943. Nor were personnel integrated in the manner of the
British Air Ministry and HQ Eighth Air Force. From the opening stages of the
Japanese attack into Burma, Allied airmen operating from India engaged in
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