Lessons about Burdens on American Cryptology
The Winds message controversy does have lessons about burdens and pressures on pre-war American cryptology, say the authors of the West Wind Clear report.
“By December 1941 American cryptology was a system that was stretched to the limit and pushed in too many directions,” they write. The American intelligence people had “conflicting missions” and too “few resources.” The ordersto monitor commercial Japanese broadcasts for a Winds execute message was just one more burden—“one more apple of chaos tossed into an already turbulent crisis.”
“The result of this skewed emphasis was that many messages encrypted in cryptographic systems other than Purple [Japan’s high-level cipher machine used for diplomatic traffic] usually took days, even weeks, to get processed to the point where a translation could be produced. After Pearl Harbor, when American codebreakers got around to decoding and translating some of the pre-attack diplomatic traffic, they discovered that many messages carried important details about the Japanese intentions.”
An example was a Tokyo message sent December 6 to its diplomats in Bangkok. It noted that “X-Day,” or “Declaration Day,” was set for Sunday, December 7 (December 8 in Tokyo). “Notice” was to be given on that date. That message was translated on December 8.
This “X-Day” was never mentioned in any Purple messages to Washington intercepted and worked by the Americans.
The report is filled with many other examples of how potentially critical intelligence was missed due to delays in translation.