Pearl Harbor: The Seeds and Fruits of Infamy - Ludwig von Mises ...

Foreign Relations in an Election Year 41
the cipher. It was thanks to a suggestion by Navy communications
expert Captain L.F. Saff ord that one of his subordinates in
the Army Signal Corps, who had been struggling with the problem
for some time, was fi nally able to solve the puzzle. 27
After the Japanese diplomatic code was deciphered, the U.S.
government was able to read all of Japan’s diplomatic messages to
and from Tokyo and her representatives in all the capitals of the
world. We referred to Japan’s diplomatic code as “Purple” and to
the information derived from reading it as “MAGIC.”
Destroyers-for-Bases Deal
Th e fi rst of Churchill’s several requests in his May 15, 1940,
letter was for “the loan of forty or fi fty of your older destroyers.”
27 Captain Saff ord spent many hours with this author, sharing insights gained
from his pre-Pearl Harbor work in communications and security, and talking
about his experiences and his knowledge of the Japanese intercepts. He played
an important role, not only in deciphering “Purple” in 1940, but also, as we
shall see, in the post-Pearl Harbor investigations.
According to David Kahn (Th e Codebreakers: Th e Story of Secret Writing,
London: Weidenfi eld & Nicolson, 1967, pp. 10, 388, 503–04):
Commander Laurence F. Saff ord . . . founded the Navy’s communication-intelligence
organization. . . . One of his principal accomplishments
before the outbreak of war was the establishment of the
Mid-Pacifi c Strategic Direction-fi nder Net and of a similar net for
the Atlantic, where it was to play a role of immense importance
in the Battle of the Atlantic against the U-boats. . . . He [Saff ord]
built up the communications intelligence organization into what
later became OP-20-G and, by adding improvements of his own
to Edward Hebern’s rotor mechanisms, gradually developed cipher
machines suitable for the Navy’s requirements of speed, reliability,
and security. . . . [H]e is the father of the Navy’s present cryptologic
organization. . . . Th anks to Commander Laurance F. Saff ord head
of OP-20-G and father of the Navy’s communications-intelligence
organization, the United States had, upon its entrance into the war,
an Atlantic arc of high-frequency direction-fi nders to exploit the
U-boat garrulity.