大象传媒

Message 1 - Re: Bob Biggs Codebreaker The day I helped the US gain revenge for Pearl Harbour

Posted on: 22 August 2005 by Peter - WW2 Site Helper

Dear CSV Kent

I am very much interested in cryptography and in intelligence gathering in general and I was intrigued by Mr Biggs reminiscences of his time spent at Bletchley. He refers to the Far East Desk, but I have never heard of that. The work on Japanese signals at Bletchley Park was done in Hut 7 and due to the secret nature of the work other staff at Bletchley were totally unaware of what went on in Hut 7, it would be simply referred to as Hut 7 rather than the 'Far East Desk'. So far as I am aware only part of the deciphering was done at Bletchley, much of the main work on Japanese signals was done in Kilindini, New Dehli and Colombo. All those involved, so far as I am aware, were top Japanese linguists, brought up to scratch by a six months' intensive course arranged by John Tiltman and run, initially at least, by Captain Tuck.

Mr Biggs mentions a message from the Solomon Islands which helped crack the Japanese code, the message beginning "Running short of ammunition and supplies ...". This almost certainly would have been encyphered in the Japanese Water Transport Code, an army code, and has no connection with the second message regarding Yamamoto, which was a JN-25 signal, used by the Japanese Navy. Could Mr Biggs comment on this?

If Mr Biggs has remembered correctly, then several specialist and popular books on intelligence gathering in WW2 are wrong and will have to be amended, and his will be a very important contribution to the Archive. In 1993 Oxford University Press published "Code Breakers - The Inside Story of Bletchley Park" edited by F. H. Hinsley and Alan Stripp. Harry Hinsley was at Bletchley Park from October 1939 and Alan Stripp was at BP in the Japanese codes section (Hut 7). Harry Hinsley was one of the editors of the five volumes on British Intelligence in WW2, first published in 1979 no mention was made of Ultra, and Hinsley did not break his silence until his 1993 publication, a decision which surprised some who worked with him at Bletchley. The section on Japanese codes (Chapter 27 - 'Bedford - Bletchley - Kilindini - Colombo') was written by Hugh Denim, himself heavily involved in deciphering Japanese codes both at Bletchley and at Kolondini. Of the work done on Japanese codes at Bletchley, he says:

"When we arrived at Bletchley in August 1942 the only available current Japanese naval intercept traffic was that from the station at Flowerdown near Winchester. It must have been forwarded by courier, because it took several days to arrive. In September 1942 we managed to have it teleprinted. Presumably this was done by land-line unencyphered. ... The Japanese Naval Section [at Bletchley] had virtually no current messages to work on, and was not in touch with customers. No desk in the section had contact with the operational world. ... The section was equally unfitted for research work - that is to say, for studying unsolved systems. ... it took us three months to get so much as a map of the Solomon Islands, where the fighting then was. ... Quite a lot of the effort was spent in editing signals from Washington and sending them to Kilindini. ... As far as I am aware, at that time we did not possess the means of transmitting teleprinter text securely by high frequency. Operational centres for signals intelligence, therefore, had to be near their point of intercept [hence the need for the Kilindini and Colombo stations]. With one exception, as far as I have discovered, none of those who worked there [Bletchley] remembers doing anything useful. In the words of one colleague, 'the recoveries that the section made and circulated were few, tentative and regarded with condescension'. This statement agrees with the impression which we formed at Kilindini and Colombo. The exception was study of the Japanese cypher machines, called Judy (Naval) and Coral (naval attach茅), which were only worked on at Washington and in the United Kingdom, and where it is understood that the section at Bletchley made contributions of value." (page 269 - op cit).

As to the message which proved fatal to Yamamoto, that wasn't in the army 'Water Transport Code', but in the far more inpenetrable JN-25 Japanese Naval code. In "Action This Day - Bletchley Park - from the breaking of the Enigma Code to the birth of the modern computer" edited by Michael Smith and Ralph Erskine. Michael Smith is a former codebreaker (he also wrote 'Station X' and 'The Emperor's Codes') and Ralph Erskine is acknowleged amongst academics as a leading historian of WW2 codebreaking, he contributes to two academic journals: "Intelligence and National Security' and 'Cryptologia'. Michael Smith himself wrote the section on the Japanese codes, this is an extract:

"Bletchley Park was not in any way involved in what was perhaps the most controversial use of the ability to break the high-level codes - the shooting down, in April 1943, of the aircraft carrying the Japanese Navy's Commander-in-Chief, Admiral Yamamoto Isoruku. A JN-25 message giving the itinerary of a tour by Yamamoto of the Solomon Islands was deciphered by the US Navy codebreakers in Hawaii ..." (page 146).

And in "Battle of Wits - The complete story of codebreaking in World War II" by Stephen Budiansky, a leading American historian of military classified studies and himself a contributor to "Action This day":

"The Japanese naval codes continued to undergo regular changes and improvements but OP-20-G [the American equivalent of Bletchley Park] had hit its stride and had little difficulty in keeping up. ... JN-25 carried about 70% of all Japanese traffic, and it too was read almost continuosly for the rest of the war. On 14 April 1943, a JN-25 decrypt landed on the desk of Edwyn Leyton, [Admiral] Nimitz's intelligence chief, and it at once electrified and disturbed him. ... It would be Admiral Isoroku Yamamoto's death warrant." (page 319).

Regards
Peter Ghiringhelli