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

Signifi cant Information Known in Washington 223
investigation was launched to discover who had been responsible
for the leak.
Japanese “Winds Code” Executed: War with
England; War with the U.S.; Peace with Russia
On November 28, we had intercepted the November 15
Japanese “Winds Code” setup (Tokyo Circular #2353), a message
announcing special weather code words to be used by the Japanese
“[i]n case of emergency (danger of cutting off our diplomatic
relations), and the cutting off of international communications.” 6
By introducing these weather words, each with a hidden meaning,
into daily Japanese language news broadcasts, the Japanese
would be able to communicate secretly to their diplomatic offi -
cers throughout the world, even if they could no longer transmit
via their cryptographic channels. Also on November 28, we had
intercepted a Japanese message with the schedule of Japanese
news broadcasts and the kilocycles on which transmissions were
to be made. 7 Th e signifi cance of the “Winds Code” message
became apparent when on December 1 we translated a Japanese
intercept ordering the Japanese diplomatic offi ces in some countries
to destroy their codes and code machines.
When Captain Saff ord, director of the Security Section of
Navy Department’s Communications, read the cable giving the
times and frequencies of Japanese news broadcasts in conjunction
with the Japanese “Winds Code” message, he put two and two
together. According to him,
6 79th Cong., 1st sess. Joint (Congressional) Committee on the Investigation of
the Pearl Harbor Attack. Pearl Harbor Attack, 39 vols. (Washington, D.C.: U.S.
Government Printing Offi ce, 1946), part 12, p. 154, Tokyo Circular #2353.
7 Joint Committee, Pearl Harbor Attack, part 34, p. 111.