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

U.S. Military Plans and Preparations 109
twice a week, so it took several days for an airmailed intercept to
reach Washington.
One J-19 message, sent from Tokyo on September 24 to
Honolulu, was picked up in Hawaii and mailed, undecoded to
Washington, where it was decoded, translated, and made available
to the top military personnel in Washington on October 9,
1941. 70 In that message, the foreign minister in Tokyo asked the
Japanese consul in Hawaii to set up a system for making regular
reports on the movements of U.S. ships in and out of Pearl
Harbor. Th is ships-in-harbor message became known as the
“berthing plan,” or as the fi rst of the “bomb plot messages.” Pearl
Harbor was not notifi ed.
On November 15 Tokyo sent a cable to Honolulu, translated
in Washington on December 3, which read, “As relations between
Japan and the United States are most critical, make your ‘ships
in harbor report’ irregular, but at a rate of twice a week.” 71 Pearl
Harbor was not advised.
On November 29 Tokyo cabled the consul in Honolulu: “We
have been receiving reports from you on ship movements, but in
future will you also report even when there are no movements.” 72
Washington decoded and translated this message on December
5. Pearl Harbor was not notifi ed.
Many other ships-in-harbor messages referring to Pearl
Harbor, some 39 in all, were transmitted back and forth between
Tokyo and Honolulu during the two months prior to the Japanese
attack. Due to the pressure of other demands on the decoders in
Washington, however, only 25 of these crucial intercepts were
deciphered, translated, and read before the attack. 73 Yet not a single
one of those 25 deciphered and translated messages was sent
70 Joint Committee, Pearl Harbor Attack, part 12, p. 261.
71Ibid., part 12, p. 262.
72Ibid., part 12, p. 263. J-19, #122. (Tokyo to Honolulu, November 29, 1941)
73 Ibid., part 12, p. 254–70.