Piercing the Fog - Air Force Historical Studies Office

Planning the Defeat of Japan
forces’ radio practices to detect possible faulty American tendencies that could
provide information to the enemy. Such overseas units, scattered across Europe,
the Mediterranean, CBI, and the Pacific, formed the basis of an AAF tactical Y-
Service. Other squadrons, like the 6th, assigned to Fourth Air Force at Hamilton
Field, and stationed in the hills above Daly City, California, immediately south
of San Francisco, worked on a more strategic level. This squadron intercepted
Japanese and other countries’ transmissions and forwarded them to Arlington
Hall Station in Virginia for decryption and analy~is.’~
On a more extensive plane, the A-2 increasingly drew radio intelligence
from MIS in Washington after the spring of 1943, when the Allies began to
have more success with Japanese Army cryptology. Most of the decrypted
message information, except for that read by the A-2 himself (who became an
ULTRA recipient), was in finished form, i.e., it came to the Air Staff as reports
or assessments of German or Japanese capabilities and intentions. Within the
A-2 office by war’s end was a small department, the Special Sources Section,
Collection Branch, that received and handled MAGIC diplomatic decrypts but
not the more general, operationally related ULTRA. Access to the MAGIC
material was tightly controlled. Although the Collection Branch’s chief and the
executive officer knew of the material’s existence, neither had authorization to
see it. The most important for the A-2 staff was, of course, ULTRA related to the
Japanese air war, as that part of the conflict was A-2’s main task. Despite the
increased use of the ULTRA source, the AAF’s intelligence analysts remained
frustrated throughout the final two years of the conflict, both because of the
method by which MIS conveyed Japanese ULTRA to them, and because of the
secrecy and restrictions imposed on its use.
MAGIC decrypts, rewritten for use by the A-2, tended to cover specific
topics extracted from regular diplomatic radio traffic, whereas the rest of the
ULTRA resembled that being taken by the British from German messages.
Because ULTRA was too fragmentary in its decrypted form, G-2 could not
prepare analyses or reports from a particular message or even groups of
messages. The best intelligence from Japanese Army ULTRA was very often
derived from the long process of decrypting, collating, analyzing, and refining,
very much like that which the MIS’s Anglo-American counterpart carried on at
BP. Final information, e.g., the OB summaries, thus reached A-2 without
notation of source, and without explanation of the reasons for restrictions on its
use and dissemination. Fueling their grumbling was not knowing the reasons for
the reports’ formats and the constraints on freedom to use the data as the A-2
staff saw fit. The worst part, of course, was that the normal air intelligence
officers could not be let in on the secret, even by the A-2 himself, who knew
the source?6 The A-2 analysts, not knowing the origin, could not trust the
product.
Still, secrecy and source protection alone did not explain entirely the
dissatisfaction, for Hodges and Quesada, themselves ULTRA readers, made
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