Yet, another WWII question

[dcunning30]

I think this may be quite easy or quite hard, I'm not shure which it will be.


How did the Japanese aid the allies in the preparation of the Normandy landings?

[Theis]

Hmm..
no idea on this one..

[ozzy72]

Was it by having really naff codes that we could read easily?

[dcunning30]

Was it by having really naff codes that we could read easily?

That sounds like a guess.  If it was, it was a really good guess.  By the time of planning for operation Overlord, the Japanese JN-25 code had been broken and was routinely read.  However the Japanese  never knew that, although some lower-level officers suspected JN-25 was cracked after the Yamamoto ambush, but the powers-to-be dismissed that notion.

Anyway, the Germans were sharing with the Japanese Embassy in Berlin it's disposition of defenses along the French/Belgium coast to defend against an allied invasion.  And the Japanese Embassy was dutifully  sending to Tokyo that information.  And the allies were eagerly reading those messages.

[Hagar]

LOL Mark's not as silly as he makes out. Well, not quite as silly anyway.

[Flt.Lt.Andrew]

Ah dang! I knew the answer to this one! I remember reading about it in The Wotan Mission by Leo Kessler (Charles Whiting). They had a big submarine and helped with supplies and codes!



A.

[Woodlouse2002]

[quote]


That sounds like a guess.

[Hagar]

I am somewhat sceptical of this as by 1944 the British code breakers at Bletchly Park were reading German signals almost quicker than the Germans themselves.

Just to point out that not all the codebreakers at Bletchley Park were British by any means. At its peak it was staffed by thousands of people from all walks of life & many different nationalities. There was a Japanese decoding section at Bletchley staffed by a large proportion of American codebreakers. Due to the large number of characters in the ordinary written language I've always thought that decoding Japanese messages must have been far more difficult than German or any other European language. Come to that I could never visualise a standard Japanese typewriter or keyboard.

makes me extremely dubious that the British highcommand had to get their infomation from Japan.

The D-Day Invasion of Normandy in 1944 was a combined Allied operation planned by American & British military experts with an American general in overall command. Every piece of intelligence would have been vital to its success wherever it came from.

[myshelf]

Due to the large number of characters in the ordibary written language I've always thought that decoding Japanese messages must have been far more difficult than German or any other European language. Come to that I could never visualise a standard Japanese typewriter or keyboard.

that actually sounds like a good research project.

a novel i once read was based on a drowned japanese sailor was found drifting somewhere around the admirality islands in '39 or '40
the code book he carried in a pouch enabling the american codebreakers to build the purple machine.

anyone knows if that was based on fact?

[Hagar]

a novel i once read was based on a drowned japanese sailor was found drifting somewhere around the admirality islands in '39 or '40
the code book he carried in a pouch enabling the american codebreakers to build the purple machine.

anyone knows if that was based on fact?

I don't know the 'purple machine' you refer to but this might be similar to the Enigma codes. The Allies already had a working example of the machine at Bletchley Park by 1940 but this wasn't much use without the codes. These were changed every day & had to be planned in advance so both the sender & receiver could use the correct daily code without which the coded message could not be deciphered by anyone except the person who sent it. This is where those codebooks come into it as the Enigma machine itself was automatic. I got most of my knowledge on this subject from a recent visit & guided tour of the once top secret 'Station X' codebreaking establishment at Bletchley Park where most of this work was done throughout WWII. http://www.bletchleypark.org.uk/

[myshelf]

I don't know the 'purple machine' you refer to but this might be similar to the Enigma codes. The Allies already had a working example of the machine at Bletchley Park by 1940 but this wasn't much use without the codes. These were changed every day & had to be planned in advance so both the sender & receiver could use the apporopriate code. This is where those codebooks come into it as the Enigma machine itself was automatic. I got most of my knowledge on this subject from a recent visit & guided tour of the once top secret 'Station X' codebreaking establishment at Bletchley Park where most of this work was done throughout WWII.

a description of the purple machine and the code can be found here:
http://mad.home.cern.ch/frode/crypto/simula/purple/

[Hagar]

a description of the purple machine and the code can be found here:
http://mad.home.cern.ch/frode/crypto/simula/purple/

Interesting. At first sight it has certain similarities to the Enigma machine but the principle it works on is not quite as easily understood, not by me anyway. The Enigma machine is beautiful in its simplicity & also very effective. I'm no cipher expert & have enough problems doing a crossword myself.

[myshelf]

well, the enigma code had severall flaws, some from the layout of the machines, some from operation procedures.

additionally, there were some big mistakes made, like "the message without L", giving the codebreakers a helping hand in breaking the enigma code.

also, the prinziple of the enigma machine was widely known, as civilian variations were manufactured in sweden and in use for encryption of buisness telegrams.
the only operational difference was the wiring of the rotors.

now for the japanese purple code the obstacles was not only the language barrier, but the use of a completely different alphabet.
the code itself was somewhat weaker, even if the theoretical numbers indicated a stronger encryption.

[myshelf]

but yes, the basic principle of all the cryptographic gear used at the time was the same.

[dcunning30]

I am somewhat sceptical of this as by 1944 the British code breakers at Bletchly Park were reading German signals almost quicker than the Germans themselves.

You're free to be sceptical, but scepticism doesn't change the facts.