"Roger Martin" write:
Message-ID:
Most amusing you posting this thru Berlin
I was always taught at school that the Brits had cracked the Japanese codes
in 1940 and had warned the US that they were to be attacked in 1941.
The warnings were ignored by Roosevelt's intelligence advisers as part of
Churchill's campaign to get the USA to join the war against the German Axis.

Lend-lease wasn't enough?
The Brits and the US cracked many codes.
I have 2 samples of raw Purple which I picked up for grins from NARA
(both about 2 weeks before Pearl Harbor).
I would not just say that there were warnings or that they were ignored.
Part of the problem is that US law until this past year does not allow
for pre-emption. There were indications of movements and a hole in
certain communications, but if definitive proof exists it has yet to be found.

The US was heavily hit by the Isolationist movement of the 30s
and wanted to avoid Imperial entanglements.


They explained how they broke the Japanese code.

The JN25 code was cracked by the Americans, at Pearl Harbor.

Perhaps a much lower level code, the Japanese Merchant's Code was
cracked at B.P.

Andrew wrote:
The Brits had been cracking the Japanese codes since the expansionist
activities threatened Singapore and the like, some time around the mid to
late 30's. The JN codes changed frequently and JN25 was the latest of many.

You refer to the recently published book The Emperor's Codes.
Yardley published his part of this in the 30s in the Saturday Evening
post and in his book The American Black Chamber. My honorable ancestors
apparently were not impressed.


The Enigma cracking was made a lot easier when examples the three wheel
enigma machines got back to the UK early in the war. That's 1939/40 and
not '41... There where different machines, not just different wheel's for
different services.

They would have saved a lot of grief were they able to talk to the US Army.

Admiral Canares suspected some of the uboat codes
Dornitz?
where being broken, in fact most where, and implemented a 4 wheel Enigma
which caused loads of grief. In the end a destroyer captured a U Boat
intact , 4 Wheel enigma machine and all and accelerated the process.
That was a British Destroyer by the way, in early '41 before Pearl Harbor
and not as Hollywood and U-571 would have you believe.

I have no idea why they chose the Nautilus hull number for that film.
571 gave credit to the various UK and US crews and the German hull numbers.
Having a machine didn't buy you much except confirming that they did it
was important. I have a a xerox from the National Archives of a memo
from England of one analyst's possessions after D-day and he had various
captured machines and code books some with blood. One of those German
code books is in the Archives complete with leaded binding for sinking.
You should write the writers care of the studio.


Mick Jagger produced the movie Engima. I think he owns one.
He certain owned the sub in the movie and he gave it to BP.


"Peter Reilley" wrote:
At Bletchley, the tour guide talked about this. When the Germans started
using 4 wheel Enigma machines, all code cracking began to fail and
the English did not know why. Then they intercepted a communication
between two German subs. The message was not encrypted and said
"Please resend your pervious message using a 3 wheel machine, we do
not have a 4 wheel machine yet". This was the clue that the English
needed. They realized that they needed to get their hands on a 4 wheel
machine.

The English had indications of the 4 wheel move. They knew it was
merely a matter of time.

4 rotor machines had to be backwards compatible as many continued to
have reasons to use 3-rotor machines. There were many of these kinds
of cribs. Some of this was covered in a Horizon/Nova special.
The real problem was resource, Bombes were in short supply.


Ian Sutherland ) wrote:
Hi folks, Just before I visited Bletchley Park in about June 2000,
No kidding, I was there in negotiations with them
at the same time. Tough budget problems for them.
Their Enigma was stolen, I think from memory on April the first. No
joke, there was quite a storm about how it could be stolen from there,
I'm sure I read that it was eventually recovered.

It was recovered.