4.8. What the British and Dutch Radio Monitors Heard
The Americans had not been alone in scouring the airwaves listening for the Winds Execute message. It was known that the British and Dutch stations in Southeast Asia also had been listening for the Winds code phrases. Did they hear anything? The best evidence provided by the Dutch and the British indicated that neither had heard any transmission of the Winds Execute message prior to the attack on Pearl Harbor. However, two cases appeared that merited further investigation. One incident suggested there was some slight evidence that the British site in Hong Kong may have heard a Winds message at some point on 7 December. In another case, the Clausen investigation mistakenly concluded that such a message might have been sent days before Pearl Harbor.
In early November 1945, the Joint Congressional Committee considered the question of whether the British or Dutch may have heard the Winds execute message. On 5 November the committee requested that the U.S. Department of State query the governments of Great Britain, Australia, and the Netherlands if they had any records of the intercept of such a message. The next day the State Department sent a message to the U.S. embassies in London, England, Canberra, Australia, and the Hague, Netherlands, that the JCC was interested to learn if any of these countries had monitored a Winds Execute message between 19 November and 7 December 1941. The message also laid out the particulars of the Japanese Winds format and the code phrases and words. [Exhibit #36][]
In mid-November the Australian Department of External Affairs reported that it had no record of such a broadcast, though it noted that not all Japanese broadcasts were monitored "verbatim." [Exhibit #37][] Over the next six weeks, the American embassy in the Hague, Netherlands, similarly relayed three messages with the response from the Dutch that their Foreign Office could find no such records of any intercept of any such Winds Execute broadcast, though the note mentioned that the records of the East Indies government had been destroyed shortly after the Japanese attacked the Netherlands East Indies. [Exhibit #38][]Safford pointed out in testimony to the Hewitt Inquiry that, in a private conversation with the former U.S. consul to the Netherlands East Indies, Walter Foote, he had been told that the Dutch radio intelligence unit had listened for, but had not heard, the Winds Execute message.[]
The British Foreign Office, though, had a different story to tell. In its 4 December response, the British recounted that while no evidence of any such Winds message was received before the attack on Pearl Harbor, it noted that the station in Hong Kong relayed to Singapore a broadcast "by the Japanese that contained messages in code and which was received in Singapore six hours following the attack on Pearl Harbor." [Exhibit #39][] The Foreign Office reported to the American embassy that the text of the "code" currently was unavailable, but could provide it if asked. There is no record that the committee asked for any further information from the British.[]
The embassy in London did relay two further British responses on the matter. The first, dated 15 December 1945, merely stated that a Foreign Office "Japanese expert" had met with the embassy staff and repeated that no "such [winds] messages" had been heard prior to 8 December, but that the investigation was still ongoing. A final message from 31 January 1946 stated that the Foreign Office had completed its search and had "drawn a complete blank."[]
What had happened at the British sites in the Far East was this. At about 8:10 PM (GMT or 2010Z; 9:40 AM in Honolulu) on 7 December 1941, the British intercept station in Hong Kong heard a broadcast that it reported as signifying that "[a] severance of Japanese relations? admitted imminent." [Exhibit #51][] While the text of the actual intercepted broadcast is unknown, the vague wording of the Hong Kong report suggests it possibly was based on a Winds Execute code phrase – "West Wind Clear." A later history of the British Far East communications intelligence organization, The History of HMS Anderson, stated that it was the Winds broadcast that Hong Kong monitored and that references to both "East" and "West" were heard. (Singapore did not hear it due to "ionospherics.") The problem with this assertion is that this portion of the history was written without recourse to records, which had been destroyed when the FECB was shut down and withdrew from Singapore before its capture by the Japanese.[] The actual message relayed from Singapore to London carried no statement as to whose relations with the Japanese were being severed. The most reasonable assumption was that this warning referred to Great Britain.
Interestingly, almost three hours earlier, Singapore had notified London of an intercept in which Tokyo had informed "all Consulates that relations between Japan and Great Britain and United States are critical." Singapore added that the message was derived from codeword[s] from table for warning telegram." This was a reference to the table of codes for the "hidden word" message.[]
Singapore relayed the information about the severed relations intercepted by Hong Kong to London at 11:12 PM (GMT or 2312Z) on 7 December 1941. It was received in London at 1:13 AM (GMT or 0113Z) on 8 December 1941. The British had told the Americans at the London embassy in 1946 that the message had been heard six hours after the attack on Pearl Harbor. If we convert the time that London received the message to the time zones of Washington and Honolulu, then the broadcast was sent at 6:12 PM (Washington) and 12:42 PM (Honolulu) on 7 December, well after the attack. This time is within an hour and fifteen minutes of when the FCC heard the "West Wind Clear" code phrase.
But the British report was mistaken. The trouble was that Hong Kong had heard the broadcast at 8:10 PM (GMT or 2010Z). If we take this time as the correct time of the intercepted broadcast, then the concurrent times in Washington and Honolulu would have read 3:10 PM and 9:40 AM, respectively. Still, even with the difference accounted for, the intercept of the possible broadcast of the Winds Execute occurred more than an hour and forty-five minutes after the attack on Pearl Harbor had begun.
There was one more claim that the British may have heard a Winds Execute message prior to 7 December. This one arose during the investigation conducted by Henry C. Clausen, the counsel from the Judge Advocate General Division, for Secretary of War Henry Stimson from 23 November 1944 to 12 September 1945. During his investigation, Clausen had received some material from the British Secret Intelligence Service (S.I.S. or MI-6). One of the items was a 3 December 1941 message from the S.I.S. representative in Manila, Philippines, Gerald H. Wilkinson, a businessman who worked for Theodore H. Davis & Company, to the S.I.S. agent in Honolulu, Henry Dawson. [Exhibit #52][]
The message consisted mostly of intelligence about military developments within Indochina. Item "C" was the important point which caught Clausen's eye:
C. Our considered opinion concludes that Japan invisages (sic) early hostilities with Britain and U.S. Japan does not repeat not intend to attack Russia at present but will act in South. (our italics)
You may inform chiefs of American intelligence and naval intelligence Honolulu, cc: Col. Bicknell, Mr. Shivers, Capt. Mayfield[]
Clausen, who had recently been cleared to view Ultra material as part of his investigations was curious about the source of information behind Item "C," that projected Japanese operations to the south while avoiding any action against Russia. Clausen was familiar with Safford's story, especially that the purported Winds Execute message also meant peace with Russia. Was the British statement based on ULTRA information, possibly either the Winds Execute message or any of Tokyo's orders to destroy codes?[] The issue remained unresolved for Clausen in late July 1945. In his interim report to Stimson dated 1 August 1945, he had stated that British sources had never intercepted a [Winds] implementation message.[]
Sometime in early August, Clausen interviewed Gerald Wilkinson and asked him about the source of intelligence in that passage from the 3 December message. Wilkinson had no idea; he merely passed along the information he had received. Clausen then queried the British government about the source. His question produced a response on 31 August from the GC&CS that stated "Colonel C[lausen] anxious to know basic source of Para. C of telegram of December 2nd [3 December in Hawaii], and in particular whether this was in 'special category.' In point of fact Para. C was based on a B.J. Wilkinson was unaware of source..." [Exhibit #53][] A 'B.J.' stood for "Blue Jacket" and was the British shorthand way of referring to translations of decrypted diplomatic messages.
Armed with this reply, Clausen amended his previous interim report which then appeared in the Army's Judge Advocate General's Supplementary Statement of 12 September 1945. It read: "The source of this intelligence was a British intercept of a Japanese diplomatic message which could have been based (our italics) upon a Japanese execute message to the 'Winds Code,' or some equivalent message."[] The Statement later repeated the comment, but referred to Clausen's finding as a "possible inference" that the Winds code would have formed the basis for the British Intelligence Service dispatch from London to Manila and then on to Honolulu.[]
There was a problem, though, with Clausen's conclusion: the British message occurred well before the date of 4 December, when Safford claimed the Winds Execute had been sent. The Wilkinson message had been sent to Honolulu on 3 December, a full day before Safford's purported Winds Execute was heard. Furthermore, the information from Wilkinson probably originated in London. Either the GC&CS or MI-6 probably composed the message, which means that, at the very least, the intelligence was available no earlier than 2 December. This is what the congressional hearings concluded after reviewing the record of translations. The source of the British information most likely was a 1 December Japanese diplomatic message from Tokyo to Hsinking, China, that read in part, "great care shall be exercised not to antagonize Russia." [Exhibit #54][]