For Keith Willshaw...

"Denyav" wrote in message
...
told the receiver what random numbers were used. Helps explain why
the USN had less than 10% of the book after 4 months.

So that means in April 1941,at the latest,US had 10% of the book in the
hand.
Can you tell us the percentage of the book available to US on Dec.4,1941?


Of the 50,000 code groups used only 3800 had been cracked

Or did US stop recovery work in April and started hibernating?

Nope the Japanese imtroduced a new 50,000 group additive
book in August 1941 which set them back months

They also had low priority, Joe Rochefort recorded that his group had
little
equipment, the tabulating machines and teletypes needed had been
diverted to the efforts to break the German and Italian codes and
the Japanese diplomatic cipher

He didnt even have a secure comms line to the radio intercept
station. All intercepts had to be delivered by courier. It wasnt
until Febuary 1942 that the group began to read even a small
portion of messages in JN-25

Keith

Of the 50,000 code groups used only 3800 had been cracked

Nope,by December almost 1000 were cracked.

ope the Japanese imtroduced a new 50,000 group additive
book in August 1941 which set them back months

Question was about April not August.
They also had low priority, Joe Rochefort recorded that his group had
little
equipment, the tabulating machines and teletypes needed had been
diverted to the efforts to break the German and Italian codes and
the Japanese diplomatic cipher

After Pearl Harbor suddenly everything changed and US (and British)code
breakers broke all codes that they were unable to crack in 12 months prior to
Pearl Harbor within a few months .
I wonder how this miracle happened,maybe your famous outer space aliens ,this
time masquerading as US (and British) code breakers made it happen.

He didnt even have a secure comms line to the radio intercept
station. All intercepts had to be delivered by courier. It wasnt
until Febuary 1942 that the group began to read even a small
portion of messages in JN-25

Even according to Safford 7000 codes were enough to read the most JN25B coded
messages and many messages could be read with 1500 codes.
Lets remember US had recovered almost 10000 codes by Dec.4

Denyav wrote in message ...
Of the 50,000 code groups used only 3800 had been cracked

Nope,by December almost 1000 were cracked.

Wrong, the December 1941 figure for JN-25B code groups
assigned meanings was 3,800.

ope the Japanese imtroduced a new 50,000 group additive
book in August 1941 which set them back months

Question was about April not August.

The reality is Denyav is unable to cope with the fact the number
in April 1941 was 300 JN-25B code groups assigned meanings.

They also had low priority, Joe Rochefort recorded that his group had
little
equipment, the tabulating machines and teletypes needed had been
diverted to the efforts to break the German and Italian codes and
the Japanese diplomatic cipher

After Pearl Harbor suddenly everything changed and US (and British)code
breakers broke all codes that they were unable to crack in 12 months prior to
Pearl Harbor within a few months .
I wonder how this miracle happened,maybe your famous outer space aliens ,this
time masquerading as US (and British) code breakers made it happen.

Translation the massive increases in resources thrown at the problem,
Hawaii had all those unemployed sailors from the sunken ships for
example, add the greater use of radio by the IJN giving more text, then
the fact that the code breakers started from knowing 3,800 meanings
in December 1941, not zero in December 1940, (and as everyone
knows it is easier to figure out a missing word in a sentence than a
missing sentence with only one word). The fact the code had uppercase
(2 meanings per code group) and auxiliary tables was known, the fact
the "next x groups uppercase" markers were well known and used as
ways to crack the messages (the difference table) in December 1941,
versus not being known in December 1940 and so on.

JN-25 was the sort of code that the more you knew the quicker you
could learn the missing parts.

Yes folks, Denyav tries to announce that the code was compromised
in 2 months in December 1940 and January 1941, but now has to
turn around and say the allies, with more resources, starting from a
much higher level of knowledge, could not compromise the code in
6 months. You see for Denyav to be right the allies went backwards
in 1942 when it came to reading JN-25. Simple really, just invent facts
and delete the problems.

By the way one of the signals used as "proof" the allies could read
JN-25 when required is the following, British dd/mm/yy format.

"XXXXX NAVAL MESSAGE T.O.O.2339A/12 IN Received: 12.2.42

Addressed: B.A.D. Washington 234
From: Admiralty
Japanese aircraft carrier SHOKAKU intends
to leave Yokosuka and pick up aircraft 9th February

It is intended preparations of First and
Second aircraft Squadrons were to complete 7th
February, sail and embark aircraft 8th. E.T.A.
Palao 1200/12th

All above from special intelligence. 2339A/12

This is now mid February 1942, with two extra
months of work, more resources, with more messages to
work on, with forward feedback in action (the fewer missing
words the easier it is to figure out the missing words, with
more of the random number encypherments known the
easier to strip them out). Note it took until the 12th to decrypt
the message which talks about the 7th in future tense, in other
words about a week to crack a simple message.

This has been used to claim real time decodings of much
larger messages in 1941.

So in mid February 1942 the allies could crack relatively
small, standard, messages after about a week.

He didnt even have a secure comms line to the radio intercept
station. All intercepts had to be delivered by courier. It wasnt
until Febuary 1942 that the group began to read even a small
portion of messages in JN-25

Even according to Safford 7000 codes were enough to read the most
JN25B coded messages and many messages could be read with 1500
codes.

Safford never wrote the work being quoted, and the example
appears to be about a special case in 1943.

Lets remember US had recovered almost 10000 codes by Dec.4

No, the 10,000 claim is straight fiction. The real number was 3,800


Geoffrey Sinclair
Remove the nb for email.

"Denyav" wrote in message
...
Of the 50,000 code groups used only 3800 had been cracked

Nope,by December almost 1000 were cracked.


1000 is less than 3800

ope the Japanese imtroduced a new 50,000 group additive
book in August 1941 which set them back months

Question was about April not August.

August comes after April

They also had low priority, Joe Rochefort recorded that his group had
little
equipment, the tabulating machines and teletypes needed had been
diverted to the efforts to break the German and Italian codes and
the Japanese diplomatic cipher

After Pearl Harbor suddenly everything changed and US (and British)code
breakers broke all codes that they were unable to crack in 12 months prior
to
Pearl Harbor within a few months .

Thats what typically happens when priorities change

I wonder how this miracle happened,maybe your famous outer space aliens
,this
time masquerading as US (and British) code breakers made it happen.


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.

He didnt even have a secure comms line to the radio intercept
station. All intercepts had to be delivered by courier. It wasnt
until Febuary 1942 that the group began to read even a small
portion of messages in JN-25

Even according to Safford 7000 codes were enough to read the most JN25B
coded
messages and many messages could be read with 1500 codes.

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

Lets remember US had recovered almost 10000 codes by Dec.4



Nope.

Keith

000 is less than 3800

Obviously 10000,sorry for typo.

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

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.

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.

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

Nope.

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

"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

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

When Japanese fleet assembled during early Nov.JN25 became the top priority and
all resources,that included cryptographers too,were assigned to JN25 reading.

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.

They did broadcast it indeed on Nov.25.
Japanase Task force broke radio silence at least 28 times during its voyage to
Hawaii.

n 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


Thats the reason why Washington cancelled Halsey's plan and removed carriers
from Pearl Harbor only a few days before attack.
Washington knew exact date and exact name of target.
WAshington was interested in producing an shock and awe event,but not
interested in losing war with Japan.
Events unfolded only a couple of months later around Midway proved that
US-British calculations were sound indeed.

By moving carriers away from Hawai just a few day prior to attack Washington
(Stark)accomplished several goals at one time.

1)The force that might deter Japanese from making the attack was no longer
available
2)Even if they were not deterred,an off shore naval battle using carriers would
not produce desired shock and awe.effect.
3)The carriers were in safety for later missions (for example Midway) whereas
Japanese were allowed to bomb useless WWI relics in Pearl Harbor.

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.

No,Sir attack order came by radio waves and it also included instructions about
how to proceed if diplomatic negotiations with US were concluded
succesfully.(No attack).
This dispatch read by British on Nov.25,Dutch by Nov.27.
When US read this message?
Its is still classified !!!.

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"


US intercepted acc.to NSA 26581 JN25B coded messages and were able to read 2413
of them.
Again according to 1946 naval inquiry 188 of them clearly indicated Pearl
Harbor as target.
Do you know a kind of radiowave that needs days or even weeks to reach
receivers a couple of thousand miles away?
Only problem now we mere mortals are not allowed to read them,except 30 or 40
of them as almost all of them were the subjects of NSA withdrawal notices.

"Denyav" wrote in message
...
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

When Japanese fleet assembled during early Nov.JN25 became the top
priority and
all resources,that included cryptographers too,were assigned to JN25
reading.


There are a couple of problems here

1) Which woud hardly give them time to crack the code by Dec 7
2) Your favorite source (Safford) reports that this happened
AFTER Dec 7th

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.

They did broadcast it indeed on Nov.25.

Feel free to prove this

Japanase Task force broke radio silence at least 28 times during its
voyage to
Hawaii.


See above

n 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


Thats the reason why Washington cancelled Halsey's plan and removed
carriers
from Pearl Harbor only a few days before attack.

The mission was real and Halsey, unlike Kimmel, put his command
on full alert.

Washington knew exact date and exact name of target.

Unsupported assertions are not facts.

WAshington was interested in producing an shock and awe event,but not
interested in losing war with Japan.

Washinton is either a city or a state and has no plans. The US government
didnt want war with Japan, it was planning to fight Germany and
unless the Fuhrer was stupid enough to declare war on the USA
a Japanese entanglement would be a serious problem.

Events unfolded only a couple of months later around Midway proved that
US-British calculations were sound indeed.


The battle of Midway happened 6 months after the Pearl Harbor
attack. Last time I checked 6 is not a couple.

By moving carriers away from Hawai just a few day prior to attack
Washington
(Stark)accomplished several goals at one time.

1)The force that might deter Japanese from making the attack was no
longer
available

The carriers were the main target as far as Yamamoto
was concerned and in harbour could neither launch
aircraft or recover them. Their presence would be
an incentive not a deterrent.

2)Even if they were not deterred,an off shore naval battle using carriers
would
not produce desired shock and awe.effect.

It was the Japanese who were pursuing shock tactics.
ANY attack would take the USA into war so there
was no advantage whatever to having Pearl harbor
not be on alert.

3)The carriers were in safety for later missions (for example Midway)
whereas
Japanese were allowed to bomb useless WWI relics in Pearl Harbor.


Trouble is the USN of the time viewed the Battleship as
the primary weapon of war and the carrier as an ancillary
vessel, it was the loss of the battlefleet that forced a
change of view.

Note those 'useless' WW1 relics went on to destroy the Japanese
fleet in the battle of the Surigao Strait in the sort of battle the
pre war planners envisaged

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.

No,Sir attack order came by radio waves and it also included instructions
about
how to proceed if diplomatic negotiations with US were concluded
succesfully.(No attack).

The message confirming the attack read 'Climb Mount Nitaka'
and was transmitted on Dec 2nd

This dispatch read by British on Nov.25,Dutch by Nov.27.
When US read this message?
Its is still classified !!!.


Ah one of your mysterious 'sekrits'

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"


US intercepted acc.to NSA 26581 JN25B coded messages and were able to read
2413
of them.

Not by Dec 7th 1941

Again according to 1946 naval inquiry 188 of them clearly indicated Pearl
Harbor as target.

The text of this inquiry is at

http://www.ibiblio.org/pha/pha/hewitt/hewitt-0.html

At no point does anything there support your claim, indeed it states

"The critical period commenced on 27 November 1941, when the Japanese
force, which was to attack Pearl Harbor, secretly left Tankan Bay,
Etorofu Island and, in radio silence, proceeded undetected toward Pearl
Harbor."

and

"Almost a complete blank of information on the carriers today. Lack of
identification has somewhat promoted this lack of information. However,
since over 200 service calls have been partially identified since the
change on the first of December and not one carrier call has been
recovered, it is evident that carrier traffic is at a low ebb."

This of course flatly contradicts your claim that the attack
force broke radio silence.

Do you know a kind of radiowave that needs days or even weeks to reach
receivers a couple of thousand miles away?

Nope but I know that coded dispatches are often only read
weeks or months AFTER their transmission

Only problem now we mere mortals are not allowed to read them,except 30 or
40
of them as almost all of them were the subjects of NSA withdrawal notices.


I am familiar with and disdainful of your claim
to sekrit information. Its an extremely childish
debating technique.

Keith