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The 14-Part Message, Purple, and the Code-Breakers -- Some questions to ponder

Discussion in 'Pearl Harbor' started by CPL Punishment, Apr 26, 2011.

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  1. CPL Punishment

    CPL Punishment Member

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    :confused:The famous 14-part message that Japan thought would constitute a "declaration of war" and thereby avert the sneak-attack opprobrium (which they would have gotten in any case since the message doesn't even break off diplomatic relations), how was it sent? Short-wave directly to the IJ embassy's receiver? or by commercial telegram? I've always surmised Nomura had his own radio communications with Tokyo, but US ambassador Joseph Grew was dependent on commercial cable to communicate with Washington, in fact the Kempeitai often held up telegrams to the US embassy for up to a full day, either as harassment or in attempt to break the American code system. In any case embassies are usually established on a bi-lateral basis... if you get two acres for your grounds, I get two acres; if you get to have your own radio station, so do I, and so forth. Does anybody know the details?:confused:

    Here's another question. The "Purple" encryption system (formally the Type-B Cipher Machine) was built for the Japanese diplomatic service by the IJN Institute of Technology. It was a modified version of the IJN Type-97 cipher machine which used romaji (Japanese written in the Latin alphabet) rather than kana, phonetic Japanese using a simplified kanji script. Technically the two machines were very similar, but in practical use very different. I learned from readings from the U. S. Naval Cryptologic Veterans Association publication that code-key transmission of kana was very different from English in that there were more than twice as many dot-dash combinations as Morse code. Since the Purple system used the Latin alphabet I assume the dot-dash was standard Morse. Does anyone know details about how Purple traffic was transmitted, or why the difference between the Navy cipher machine (which they seldom used operationally) and the Japanese Foreign Ministry version?

    Finally I would love to talk about Japanese codes generally.
     
  2. Spartanroller

    Spartanroller Ace

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    Long-wave would be much more likely at those distances.
     
  3. CPL Punishment

    CPL Punishment Member

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    Not knowing at all what I'm talking about when it comes to radio I decided to research a bit. From the Wikipedia article on the subject it seems that shortwave radio was so efficient at inter-continental distances that the technology threatened the profits of trans-Atlantic cable operators. Also, it appears that shortwave needs only a relatively short antenna, whereas longwave antennae can be hundreds of meters high. I don't believe there was such an antenna on the roof of the Imperial Japanese Embassy.

    I could be wrong, however.
     
  4. Spartanroller

    Spartanroller Ace

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    it certainly could have been either - they tended to hide LW antennas inside chimneys, or using lightning dissipators and 'clothes lines' etc. For sure the SW made a better clandestine set, but an embassy isn't quite so limited in that way, not sure quite how well SW would have worked trans-pacific, but I guess they didn't have to be transmitting directly to Tokyo, could have been sent via Spain perhaps. Not sure.
     
  5. CPL Punishment

    CPL Punishment Member

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    Well, longwave or short, I suspect that the Japanese embassy in Washington had its own radio, and I suspect the Japanese consulate in Honolulu did not. I base this on the famous "flowers code" which was used to report ship movements in PH. As I recall the flower messages went by Western Union telegraph. If they had their own radio station and a cipher machine, then why not send the intel in Purple code along with the regular consulate traffic?
     
  6. brndirt1

    brndirt1 Saddle Tramp

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    You might find this section of interest, since it clearly refers to "shortwave radio" transmissions, code machines, and code books in the Japanese Embassies world wide as Dec. 1941 began.

    Goto:

    December 1941

    It seems pretty clear that it was high frequency/shortwave radio which was used. And since radio waves can be "heard" by anyone codes were needed.
     
  7. lwd

    lwd Ace

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  8. Takao

    Takao Ace

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    CPL Punishment,

    IIRC, Neither of the nations were allowed to have radio transmitters in their respective embassies, thus they all had to rely on commercial firms to get their messages out.

    I'd have to go back and re-read "Combined Fleet Decoded", But I'm fairly certain that is how it was.
     
  9. CPL Punishment

    CPL Punishment Member

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    This is an observation and a speculation rather than a statement of fact: There were two distinct cipher machines based on the same switching technology developed by the IJN, the Type-97 which encrypted/decrypted kana, and the derivative Type-B designed to work with the Latin alphabet. Using the Type-B system a Japanese diplomat had a much more flexible communications system because he need not rely on Japanese-trained telegraphers, any commercial telegraph operator fluent in the ubiquitous Morse system could handle the transmissions both ways. In fact using the Type-B would allow a hybrid communications protocol, outbound messages from Tokyo sent via shortwave and inbound traffic from the embassies and consulates via the most convenient medium available. Admittedly this would be a clumsy system as it precludes realtime requests for re-transmits in case of garbled traffic, but it does allow at least partial independence from foreign telegraph services in countries where full two-way shortwave is forbidden or otherwise undesirable. For example, I suppose a full two-way shortwave would have been undesirable for a mere consulate, such as Japan's presence in Hawaii -- an outpost of the Imperial Foreign Ministry established to serve the interests of tourists, business travelers, merchant seamen, etc. -- to generate a lot of shortwave chatter. Just the volume of traffic might alert the Americans to inordinate Japanese interest in Hawaii. However with a Type-B cipher machine and a locally available commercial shortwave receiver the consulate could be alerted to sudden developments. In fact staff members of the Japanese consulate on Oahu were seen burning books, files and other things before 7 AM on the morning of 7 December 1941. They must have received some warning from Tokyo either earlier that morning or late the previous night that hostilities were imminent.
     
  10. brndirt1

    brndirt1 Saddle Tramp

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    I do believe that it should be kept in context that HF/shortwave receivers are not to be confused with transceivers. An embassy could receive a message "in code" and reply by what is now considered land-line in code through normal embassy channels.

    Or at least that is how I can see it happening. Any Japanese embassy (in a foreign nation) receives a coded message by radio-telegraphy, and replies by standard commercial cable using embassy code.
     
  11. Biak

    Biak Adjutant Patron  

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    I'm not sure but I think this may shed some light on the initial messages.

    "" From: Tokyo
    To: Washington date: 19 NOV 1941
    Regarding the broadcast of a special message in an emergency. In case of emergency (danger of cutting off our diplomatic relations), and the cutting off of international communications, the following warning will be added in the middle of the daily Japanese language short-wave news broadcast:
    1) In case of Japan-U.S. relations in danger: HIGASHI NO KAZE AME ("east wind rain")
    2) Japan-U.S.S.R. relations: KITA NO KAZE KUMORI ("north wind cloudy")
    3) Japan-British relations: NISHI NO KAZE HARE ("west wind clear")
    This signal will be given in the middle and at the end as a weather forecast and each sentence will be repeated twice. When this is heard please destroy all code papers, etc. This is as yet to be a completely secret arrangement. Forward as urgent intelligence.
    From: THE CODEBREAKERS; The Story of Secret Writing, David Kahn]""


    (bold mine) from the old standby HyperWar;
    HyperWar: Diplomatic Documents
     
  12. OpanaPointer

    OpanaPointer I Point at Opana Staff Member Patron   WW2|ORG Editor

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    Um, the "flowers" code was not a code, it was simply a case of paranoia. The interview between the Japanese newspaper(?) and the Hawaiian was legit, not "hidden meaning."

    As 14-part message, it would have come as Morse code broadcast in code, I think. Telegram was also an option, which would explain the fourteen parts, the max amount of text for any one telegram.
     
  13. OpanaPointer

    OpanaPointer I Point at Opana Staff Member Patron   WW2|ORG Editor

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    The Winds system was never implemented, it was only for use if the normal means of communication were broken before outbreak of war, and this didn't happen.
     

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