For Keith Willshaw...

"Denyav" wrote in message
...
000 is less than 3800

Obviously 10000,sorry for typo.

August comes after April
Right but still question was about April.


A change in August is clearly signifucant when considering
the situation in December

Thats what typically happens when priorities change

No,as soon as Japanese fleet assembled in early Nov.,OP-20-GY -1 was
alerted
and devoted almost all of its resorces to JN25B messages on 7/24 basis.


But had few such resources. There were only 36 trained cryptographers
available and at any one time only a small number (2 to 5) was assigned to
JN-25

Evcen had JN-25 been cracked Pearl Harbor attack plan was never broadcast
in JN-25 or any other cipher and the fleet maintained complete radio
silence.
All that could have been surmised was that an air attack somewhere
in the Pacific was likely. This had already been surmised which is why
the carriers of the USN were delivering extra aircraft to Midway
and Wake in early December 1941 and why Force Z which was
planned to include a carrier was sent by the RN to Singapore

Yamaoto's biographer (Hiroyuki Agawa) served under him in
the IJN and is quite clear that orders for the attack were
hand delivered and extreme precautions taken within the
navy to avoid compromising the plan.

Extra money, people and equipment made it happen, just as the
US armed forces increased in size rather quickly, this tends
to happen during a major shooting war.

Problem is that the US knew that it was going to happen almost one full
year in
advance.


No they knew AN attack was coming but the expected venue
was the Phillipines.

Safford is not a good source, but since only 3,800 had been cracked !

Safford is pretty good source if you add up monthly totals you will find
another number


Your misrepresenting his words isnt helpful.

Nope.

True sir US,(and Probably Brits) were able to read almost 90% of Jn25B
dispatches prior to Dec.7

No sir they were not, the data released from Bletchley Park
as written about in 'The Emperors Codes' by Michael Smith
makes it quite clear that neither nation was reading
JN-25 at that time. This is reinforced by the
"History of OP-20-GYP-1"


Keith