THE SINKING OF THE AUTOMEDON, THE CAPTURE OF THE NANKIN

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP90-00965R000605710002-4
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 8
• Document Creation Date: December 22, 2016
• Document Release Date: June 27, 2012
• Sequence Number: 2
• Publication Date: May 1, 1985
• Content Type: OPEN SOURCE

STAT
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May 1985
games Rusbridger
The Sinking of the "Automedon",
the Capture of the "Nankin"
New Light on Two Intelligence Disasters in World War II
THE CL?LEBRATIONS last year
and this-surrounding
the 40th anniversary of
the D-Day landings in Nor-
mandy and the VE-Day victory
eleven months later-pro-
duced many reminders of the
various stratagems the Allies
employed to deceive and con-
fuse the enemy as to our
intentions, and the associated
Intelligence operations that werr developed to eavesdrop
upon the Germans' innermost deliberations. Due to an
almost total absence of German archival material it has never
been possible to establish beyond Al doubt how many of
these schemes worked as well as we like to believe they did,
for in truth German Intelligence at operational levels-as
opposed to that at command level-was of a very high order.
In the euphoria of victory and with the passage of time it
is often forgotten that the Germans had their share of
Intelligence coups too, just as dramatic and with equally far-
reaching consequences as those the Allies perpetrated.'
Over the past ten years the release of archival material
regarding the role during World War II of "Signals
Intelligence" (SIGINT)-the art of eavesdropping upon the
enemy's radio traffic-has provided some public access
to the work of the ULTRA code-breaking organisation. This
was, to give it its official title, the Government Code and
Cipher School (the forerunner of today's Govern-
ment Communications Headquarters). which was located at
Bletchley Park, near London, and to a somewhat lesser
extent the Signal Intelligence Service in Washington, D.C.,
its US counterpart. The flow of hooks and television
documentaries based on this material have mainly con-
centrated on the penetration of German ciphers. As yet.
no Japanese ULTRA intercepts have been released by the
' See, on the European front, the articles in ENCOUNTER by the
Dutch historian Louis de Jong: Was 'Arnhem' Betrayed?" (June
1981). and "The 'Great Game' of Secret Agents" (January 1980):
and Robert Cecil. "Legends Spies Tell" (April 1978).
British Foreign Office into the Public Record Office at Kew,
and the latest information suggests that there is little chance
of this happening in the near future.
Because of the sensitive and controversial nature of Signals
Intelligence and code-breaking, there is still much
confusion-and a great deal of patriotic mythology-about
exactly what was achieved during the last War, how it
affected-. the outcome of individual battles, and-more
importantly-what successes the enemy had with their Signals
Intelligence and code-breaking activities against the Allies.
Not surprisingly, because of their love of secrecy, the
agencies involved have been only too happy to foster this
confusion especially in cases where the reputation of a famous
political leader or military hero is involved-e.g. Churchill
or Field-Marshall Montgomery.. whose apparent prescience
during the War has become part of our history. The years
pass, and those still alive who worked at Bletchley Park, and
have first-hand experience of what went on there, dwindle in
numbers and have been forbidden to publish their. stories (or
even to see their own wartime files, which are now kept at
GCHQ at Cheltenham). An official history of Bletchley Park
was,\vritten shortly after the War; but this has never been
published, and there appear to be no plans to do so in the
future.
Equally. there has been a surprising lack of definitive
accounts from German sources detailing their wartime
Signals Intelligence and code-breaking operations. Initially.
this was due to the unavailability of the relevant records
because, at the end of the War, all these were removed.
either to London or Washington, for inspection by the Allies.
It is clear that when these archives were repatriated to Bonn
in 1958 quite a number of files were retained under the
Anglo-American agreement, arranged immediately after the
War, that there was to be no public release of any wartime
material dealing with code-breaking, "double-agents", or any
of the variety of deception schemes (and other ruses) that had
been employed against the enemy.
Furthermore, it was not long after the War's end that the
political tide began to change and the US Central Intelligence
Agency started recruiting German Intelligence personnel
(with scant consideration for their wartime activities or
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James Rusbridger
behaviour) in order to prepare for the new Intelligence duel
with the Soviet Union. Not surprisingly, it was considered
inadvisable to encourage our past enemies to publish details
of their wartime successes against the Allies. These might
have a direct bearing on current operations not only against
the USSR and her allies, but also against other nations which
were still using variations of the Enigma cipher machine.
All the available evidence does confirm, however, that in
the years leading up to the outbreak of World War II in 1939
the Germans had developed an extremely efficient Signals
Intelligence organisation (usually known as B-Dienst), which
was regularly reading British diplomatic, Naval. Army, Air
Force, and Merchant Navy ciphers with ease. The cause of
this was the British Government's reluctance to adopt the
principle of "machine enciphering." During the 1920s, this
had been progressively developed by three principal
inventors: Boris Hagelin and Arthur Scherbius on the
Continent, and Edward Hebern in the United States.2
In the mid-1930s, the late Lord Louis Mountbatten had
strongly recommended that the Royal Navy adopt machine
enciphering, using the Enigma, of which two had been bought
by the Admiralty in 1928. Unfortunately, no action was
taken. When the War started the Navy was still using the
cumbersome and outdated "book ciphers" which had hardly
changed since World War I. These tabular columns of four-
and five-figure groups, employed in conjunction with
subtractor tables, were time-consuming in use, and prone to
arithmetical error. In addition, the system suffered from a
primary disadvantage: if any one set of code hooks was
captured, new sets had to be issued to all the ships in that
particular group-and in wartime that could be a-very lengthy
procedure.
By contrast, the Enigma consisted of a machine about the
size of a portable typewriter, with a standard keyboard, three
(later, four) interchangeable rotors, and a number of plug
connectors. Together it offered 200 quintillion permutations,
and yet it could be used without difficulty by semi-skilled
operators under the most extreme battle conditions. The
rotor settings could be changed daily (or several times a day)
according to the number of messages transmitted; each
setting produced 17,576 different positions, after which the
rotors returned to their original setting.
Of these three. Arthur Scherbius is the best remembered
because he produced the Enigma cipher machine. Boris Hagelin
eventually supplied cipher machines to the US Armed Forces and in
the process became a millionaire (he set up his own cipher-machine
factory in Switzerland after the War. and today it leads the world in
cryptographic technology).
` The pilot of the plane. Hugh (--Jimmy--) James. managed to
crash-land in names, whereupon the German fighters, circling
overhead, dived in attack tune and again. General Gott survived the
landing, but was killed during these attacks (see Daily Telegraph,
London, 8 and 12.June 1984).
Less than a year later, in April 1943, American code-breakers
intercepted a message detailing the proposed inspection tour by
Admiral Yamamoto of the Solomon Islands: fighters from
Henderson Field attacked his aircraft and shot it down. causing a
terrible blow to Japanese morale at the loss of their great hero.
' Bernhard Rogge and Wolfgang Frank, Schiff /6 (Stalling Verlag,
Hamburg. 1955); Ulrich Mohr, Atlantis (London, 1955).
PART FROM RADIO INTERCEPTION and code-breaking,
Hitler's Intelligence Services had also captured large
quantities of secret cipher material from the various
British Embassies and Consulates in Scandinavia during
April-May 1940. A complete set of current Naval ciphers was
seized from the submarine HMS Seal, captured off the
German coast in 1940. There is still some mystery
surrounding this incident, because nearly an hour passed
between the submarine being forced to the surface and
surrendering, yet no attempt was made to throw the ciphers
overt s d. On 11 September 1942, a motor torpedo boat was
captured by the Germans which again yielded valuable cipher
material. Similar secret Naval documents were found in
Royal Naval vessels lost off Crete.
German Intelligence was also adept at exploiting specific
coups. For example, in August 1941 an Italian employee at
the US Embassy in Rome picked the lock of the safe used by
the Military Attache, Colonel Fiske, and photographed his
cipher (sometimes called the "Black Code"), which was then
passed on to the Germans. For the next 18 months or so, they
were able to read all American military attache traffic around
the world,
In particular, the "Black Code" enabled Field-Marshal
Rommel to monitor the daily reports from Colonel Frank
Fellers, the US Military Attache in Cairo, who sent back to
Washington detailed summaries of the military and
diplomatic plans of the British Middle East operations.
Churchill was anxious that President Roosevelt should he
apprised of what was happening in the Middle Gast, and
Colonel Fellers was invited to attend all the most secret
briefings. For it long time Rommel was credited with
possessing almost magical powers in anticipating our next
move in the Desert War-although, in fact, he was doing no
more than we were with our ULTRA intercepts of German
signals.
One result of this precious insight into our intentions was
that the Germans learnt of the appointment of General
William ("Strafer") Gott as Commander of the 8th Army,
and of his plan to fly to Cairo on 7 August 1942 to take up his
appointment. Gott's Bristol Bombay transport aircraft took
off from a small airstrip at Burg-el-Arab and was immediately -
attacked by six Messerschmitt 109f fighters which had been
lying in wait.3
The "Automedon" Windfall
0 NE PARTICULAR THEATRE of operations where the
Germans enjoyed spectacular success was in
the Indian Ocean where their surface raiders
intercepted, sank, or captured a vast tonnage of Allied
merchant shipping. German accounts of these operations'
appeared soon after the War but concentrated on the
buccaneering aspect of the raiders' exploits: and the full
extent to which they used Signals Intelligence and crypt-
analysis has come to light only recently.
One of their early successes was the capture by the raider
Atlantis (on II July 1940) of the steamer City of Baghdad,
from which was taken current copies of the Merchant Navy
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10 The Sinking of the "Automedon", the Capture of the "Nankin"
cipher and secret call-signs that enabled the captain of the
Atlantis. Bernhard Rogge, to read messages for other Allied
merchant shipping, plot their likely course, and intercept
them without difficulty. On several occasions prisoners were
told by the Germans the name of the vessel they would
intercept the next day, and each time this proved correct.5
The raiders were practised at sending out false messages
which cancelled the distress calls of those ships they had
captured.
On 10 September 1940, using this technique, the Benarty
was secured and more secret mail seized; then, on 11
November, the Blue Funnel steamer Automedon (7,528 tons)
was intercepted by the Atlantis off the Nicobar Islands. In
order to stop her using her radio to send a "Raider Sighted"
report, the Atlantis shelled her with 28 rounds from her 5.9
inch guns (wrecking the vessel and killing Captain McEwen
and two officers and a steward on the bridge).
The German boarding party was led by Lieutenant Ulrich
Mohr, who had an excellent knowledge of English. Forcing
open the strong-room they seized some 60 packages of mail
including all the top-secret post en route for Far Eastern
Command, Singapore. Among their haul were the new Royal
Navy fleet ciphers; new Merchant Navy ciphers valid from
I January 1941; Admiralty weekly shipping intelligence
summaries; and a host of other sensitive documents. There
was also six million dollars of new Straits currency notes,
fresh from the Treasury printers in England.
THE SINGLlMOST IMPORTANT ITEM, packed in its own weighted
canvas bag marked "SAFE HAND--BRITISH MASTER ONLY",
was a copy of the .War Cabinet Minutes for 8*-August 1940,
which included the highly secret Chiefs-of-Staff report on the
defence of Singapore and the Far East against Japanese,
attack. which was being sent to Air Chief Marshal Sir Robert
Brooke-Popham. C.-in-C. Far East.'
This document consisted of 87 detailed paragraphs, and
was most gloomy in tone. It flatly stated that Britain was not
in a position to resort to war if Japan attacked French Indo-
China or Siam, and that Hong Kong, Malaya, Singapore, and
the Dutch East Indies were indefensible since we would be
unable to spare sufficient forces from other theatres of war to
match the Japanese. It seems incredible that such a valuable
document should have been sent to the Far East on a slow,
vulnerable, merchant ship when the flying-boat service to
Singapore was still in operation. Lieutenant Mohr im-
mediately recognised its importance when he and captain
Rogge inspected their haul.
Having sunk the Automedon, the Atlantis immediately
' File 1/61/2/7 and MPI/587/22/153S. Australian Archives.
Canberra.
" CAB/65/8, Public Record Office (Kew). COS (40) 592. 31 July
1940, now CAB 66/10, Public Record Office. Letter from Squadron
Leader G. H. Wiles (Air Ministry. London. dated 15 July 1948) to
Air Marshal Sir Robert Brooke-Popham.
209/40-212/40 gKdos, Oberkommando der Kriegsmarine (OKM)
signal log, and SRNA 0020, RG 457 (National Archives.
Washington, D.C.).
sailed for the Mandated Islands where the Japanese had been
providing a safe harbour and refuelling facilities for German
raiders. The mail and prisoners were transferred to the
captured Norwegian tanker Ole Jacob which at once sailed
for Japan carrying 10,000 tons of aviation gasoline. When it
reached Kobe, on 4 December, the prisoners were taken
off at night-to avoid them being detected by the British
Secret Service who had the movements of German vessels
under surveillance-and transferred to the liner Scharnhorst.
MAIL FROM THE Automedon reached the German
Embassy in Tokyo on 5 December and was
immediately inspected by Admiral Paul Wenneker,
the German Naval Attachd. He photographed the most
important items, including the Chiefs-of-Staff report, before
sending them off to Berlin in the custody of a German Naval
officer, Paul Kamenz, who crossed to Vladivostok and then
travelled on across Russia, via Moscow, by train.
On 7 December Admiral Wenneker sent a long four-part
cipher telegram to OKM Berlin (Oberkommando der
Kriegsmarine). the German Navy headquarters, summarising
the main parts of the Chiefs-of-Staff report. Because this
message went by postal telegraph circuit across the Soviet
Union it could not be intercepted by the British code-
breakers at Bletchley Park. On 12 December the Japanese
Naval Attache in Berlin. Captain Yokoi, on the express
orders of Hitler, was shown a copy of Wenneker's summary.
Yokoi then sent his own shortened version back to Tokyo-
and this message was intercepted by the Americans .... 7
However, because it was in the Naval Attachd's cipher, it
could not be read (the signal was not decoded until after the
War, on 19 August 1945).
On 12 December Admiral Wenneker gave copies of the
Chiefs-of-Staff report to Vice-Admiral Kondo (then Vice-
Chairman of the Japanese Naval General Staff). At first he
could not believe that the documents were genuine,
suspecting that they had been deliberately allowed to fall into
enemy hands in order to mislead both the Germans and the
Japanese. However, when Wenneker explained how they had
come to be captured, and the loss of life involved, Kondo
accepted the authenticity of this almost incredible windfall.
There is no doubt that possession of these documents
profoundly affected Japanese war planning in January 1941.
This intimate view of Churchill's War Cabinet decisions and
opinions enabled the Japanese to dismiss any serious fears
that the British could make a worthwhile military inter-
vention in the Far East. It also provided the Japanese with
a clear picture of British knowledge of their armed forces (for
example, that we were unaware that the Japanese Air Force
possessed torpedo-carrying aircraft).
It is fair to argue. therefore. that the capture of the Chiefs-
of-Staff report from the Automedon was the catalyst that sent
the Japanese on the path to Pearl Harbour and precipitated
the ruinous attack on America's Pacific fleet.
After the fall of Singapore in 1941, Captain Rogge of the
Atlantis was presented with a samurai sword by the Japanese
Emperor in recognition of his achievement. Only two other
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James Rusbridger 11
Germans received such an award-Hermann Goering and
Erwin Rommel. Later, Admiral Kondo was to tell Wenneker
on several occasions how valuable this particular document
had been in planning the attacks on Pearl Harbour, the
Philippines, and Singapore, on 8 December 1941, thus
opening the war between Imperial Japan and the USA.
Despite the heavy shelling the Automedon had managed to
send out a "Raider" report which, although incomplete, was
intercepted by at least two ships, the Matara and the Helenus.
On 30 December 1940, British Naval Intelligence in
Singapore learned from a member of the Norwegian crew of
the Ole Jacob that the Germans had seized all the mail on
board the Automedon, and advised the Admiralty in London
accordingly."
The surviving members of the crew of the Automedon were
brought back to Europe in the German blockade-runner
Storstad, arriving at Bordeaux on 5 February 1941. After
being held in a PoW camp for a month, they were taken (on
March 12) to the railway station for transfer to another PoW
camp near Munich.'
THE END OF THE WAR the British Government
AT considered the Automedon affair so sensitive,
bearing in mind the effect ihhad had on the outcome
in the Far East, including the fall of Singapore-that all
reference to it was to be withheld from the public. As a result.
no files about the incident are to be found in the Public
Record Office at Kew. "'
Public knowledge of the loss of the Cabinet documents
came to light quite accidentally when, in 1980, the US
" Stephen Wentworth Roskill, The War at Sea 1939-45: Vol. 1, The
Defensive (HMSO, London), p.282. Common Services Records
(London), and Modern Records Centre (Liverpool), 20 September
1984.
While travelling across France, the Automedon's Fourth
Engineer. Samuel Harper, jumped from the train during the night
and started to make his way across France to freedom. By a series of
fortunate coincidences he met with friendly and helpful Frenchmen
who passed him on from one town to another until on 18 March he
finally reached Marseilles. On 4 April he was taken by a party of
smugglers across the Pyrenees, eventually reaching Spain on 13
April; he was promptly arrested and taken to a prison in Barcelona.
The British Embassy secured his release on 29 May and, after being
taken to Madrid for a medical check-up. Harper finally reached
Gibraltar on 31 May 1941. (Modern Records Centre. Blue Funnel
Line Archives. Liverpool.)
"' Search Department, Public Record Office (4 September 1984),
on821.
John Costello, The Pacific War (Collins. 1981), p.614.
= Historical Section, Cabinet Office (London). 23 August 1984.
Letter from Squadron Leader G. H. Wiles. 15 July 1948. Permanent
Under Secretary's Department. Foreign and Commonwealth Office
(London), 2 February 1984.
" Letter from Lord Dacre to Mac Keen, Assistant Managing
Editor, Daily Mail, London, January 1984.
" Private correspondence (August 1984) with Colonel Brian
Montgomery, author of Shenton of Singapore (Seeker & Warburg,
1984), and Hugh Humphrey, CMG, OBE, who in 1940 was Sir
Shenton's private secretary.
National Security Agency declassified over 130,000 pages of
wartime MAGIC decrypts, (the word MAGIC being equivalent
to the British ULTRA). Among these was the intercepted
message from Captain Yokoi and, when this first publicly
appeared in 1981,11 it became possible to trace the lost papers
back to the Automedon.
Even today, after nearly 45 years, the incident is evidently
considered so embarrassing that the Foreign Office will not
admit that the loss ever occurred, despite the fact that the
captureg4ocuments were found in the German Foreign
Minis6archives in Berlin in 1945. In 1983 1 asked the Prime
Minister, Mrs Margaret Thatcher, to inquire into the matter.
After a delay of seven months, the Foreign Office advised me
that it would be "improper" for me to know the facts of the
incident, but hinted that the documents had perhaps been
passed to the Russians, and thence to the Germans, by the
exposed Soviet spy Donald Maclean. 12 Lord Dacre, who as
Hugh Trevor-Roper was responsible for sifting through many
German archives after the War, expressed the view that any
suggestion that secret War Cabinet Minutes had been lost to
the enemy in 1940 was "highly questionable" and that no such
papers had been found among the German records. to
Although by the end of 1940 Churchill and his War Cabinet
were aware that their most secret plans for the defence of
Malaya and Singapore had fallen into enemy hands, neither
the C.-in-C. Far East, Brooke-Popham, nor the Governor of
Singapore, Sir Shenton Thomas, were told of the loss."' This
is particularly surprising because on I August 1940, while on
leave in London, Sir Shenton Thomas had put his case for the
defence of Singapore and Malaya personally to the Joint
Planning Sub-Committee of the War Cabinet and many of his
recommendations were incorporated in the ill-fated report.
After the War Sir Shenton was very critical of the manner in
which the official account of the loss of British possessions
east of India was prepared. Indeed, he was not even
consulted before the official history of the war against Japan
was written-although he had come in for a considerable
amount of criticism for the ease with which Singapore fell to
the enemy. Had Sir Shenton (or his C.-in-C., who died in
1953) known that our entire defence plans had been in enemy
hands for a year prior to hostilities commencing, he would
surely have made some pertinent comment before his
untimely death in 1962. One can only deduce that, for one
reason or another, Winston Churchill had decided not to tell
the authorities in Singapore.
J T ALSO APPEARS THAT neither the Australian nor the New
Zealand Governments were told of this catastrophe-
despite the fact that the British Chiefs-of-Staff report
had been specifically prepared to satisfy their queries about
Britain's intentions concerning the defence of the Far East in
the event of a Japanese attack. In 1941 the Chiefs of Staff
prepared another report on the defence of Singapore and
Malaya, again in reply to a query from Prime Minister Robert
Menzies of Australia. But this does not mention the loss of
the previous report, nor is there any comment about this in
the Minutes of the Defence Committee for 9 April 1941.
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12
The Sinking of the "Automedon", the Capture of the "Nankin"
when the defence of the Far East was also discussed in
detail .'s
The "Nankin" &
the Compromised Cipher
A Itrl -t-ii rill : it nto,nedon affair was disastrous, it
pales into insignificance compared to what happened
when the Australian steamer Nankin was captured
by the German raider Thor on 10 May 1942.
The Nankin had sailed from Fremantle on 5 May under the
command of Captain Stratford with a crew of 180. 162
passengers (including 38 women and children), and 18 naval
and 5 military personnel. Once again it is clearly evident that
the German raider had advance information of the Nankin's
movements.
In the early afternoon, an aircraft circled the ship (and then
made it very low pass in an attempt to tear away the wireless
aerial). Shortly afterwards the Thor was seen approaching,
and when the Nankin broke radio silence and attempted to
transmit a "Raider Sighted" signal, she opened fire. After an
hour-long engagement during which there were fortunately
only light casualties, Captain Stratford decided to
surrender-but not before throwing overboard the ship's
code-books and confidential papers." The Thor was then
joined by her supply vessel, the'Regensburg, and the three
vessels remained together from 12 May to 28 May while the
passengers, the crew, and the Nankin's valuable and useful
cargo welt transferred to the two German ships. (This clearly
demonstrates how good the Germans' Signals Intelligence
had become, for they evidently felt it quite safe to remain
together for a long period.)
Among the Nankin's cargo the Germans found a large
quantity of mail. There is some dispute as to how much there
was: one report mentions 400 sacks of ordinary mail and 56
sacks of secret courier post, while another report (which
seems the more likely), speaks of only 120 sacks.'? The bulk
of the mail was quite routine material, mainly consisting of
letters and packets from South Africa, New Zealand. and
Australia, destined for England; but there was also a small
amount of very secret mail from the Combined Operations
Intelligence Centre at Wellington, New Zealand. en roue to
C.-in-C. Eastern Fleet (Colombo).
COIC (sometimes known as the Central Intelligence
Bureau) was first established in 1940 in an office next door to
New Zealand's central War room in Stout Street, Wellington.
It was an offshoot of the Prime Minister's group called the
"Organisation for National Security", which began work in
" Secretary of War Cabinet, 5 August 1940, WP (40) 302. now
CAB 66/10 at Public Record Office. COS 230/41. Defence
Committee (Operations) 12/41. now CAB 69/2, PRO.
" Australian Naval Archives. 2026/10/1854. MPI/1185/8. Box 21.
" Paul Carell. "Gespenster auf Hoher See". Kristall Magazine
(Hamburg). Vol. 13. 1958. Foreign Ministry files. Berlin. Pol Vili.
1064/42. now at Bundesarchiv. Freiburg.
'x New Zealand Archives (Wellington). Navy Series List.
Series 11.
1938 keeping records on Japanese (and other aliens) in New
Zealand. COIC coordinated the Intelligence activities of New
Zealand's Army, Navy, and Air Force, and had close links
with the Police and Customs Service; it also worked closely
with the British, American, and Australian Intelligence
Services from which it received a great deal of very sensitive
information, much of which dealt with matters far outside the
Australasian theatre of operations.
Each week COIC issued a "MosT SFCRr:T ' intelligence
summary" which was distributed on an "Officer Only" basis
to 22 named recipients, including the C.-in-C. US Pacific
Fleet~:Admiral Chester Nimitz. A further warning inside each
sun rlhary stated that the contents came from "Most Secret
Sources", an expression coined by Churchill to denote that
the information was of ULTRA classification and had been
obtained from cryptanalysis.
Each summary was divided into four parts. The first,
dealing with 'information about the ANZAC theatre of
operations, gave details of Allied shipping, naval vessels,
convoys, and so forth. The second part concerned external
intelligence and appears to have covered any part of the
world (it included, for example, weekly convoy tonnages
arriving in the United Kingdom-which seems a strange piece
of information to send all the way out to New Zealand). Part
Three provided information on Japanese forces and general
comments about Japan's economy. while Part Four gave a
detailed list of the estimated disposition of Japanese naval
vessels in the Indian and Pacific Oceans and their likely future
movements. A separate appendix then gave the latest details
of every Allied vessel in the same area and their future
movements.
SOME OF THE INFORMATION in these summaries came from
normal sources such as air reconnaissance; interrogation of
prisoners; the coast-watcher service, which involved agents
living behind Japanese lines and radioing reports to the
Intelligence Services; and analysis of regular radio traffic
passing between ships at sea and their land bases. But it was
equally obvious that much of the very detailed knowledge of
the whereabouts of enemy ships and their intended
movements could only have come from code-breaking; and it
seems, therefore, that the COIC was receiving a great deal of
information from the US Navy's cryptanalysis organisation in
Hawaii.
This was known as the Fleet Radio Unit (FRuPac), which
had a subsidiary headquarters at Belconnen, in Australia.
These two teams of cryptographers had been intercepting.
analysing, and slowly penetrating the most complex Japanese
operational cipher, which the US Navy called JN2S. It is
outside the scope of this article for me to attempt to describe
in detail the principle of the JN2S fleet cipher, but it involved
an elaborate system of double-encipherment using a number
of different tables of figure-groups each of which was
regularly changed. Although it was not a machine cipher like
Enigma, or that used by the Japanese for their diplomatic
communications, it was still considered impossible to break.
The Americans naturally guarded the secret of their code-
breaking activities very carefully; and it is not yet clear
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lames Rusbridger
13
whether FRUPac was aware of how much information was
being passed to COIC, or to what extent COIC was
redistributing it. The late Admiral Layton USN (he died in
May 1984) was Nimitz's Fleet Radio Officer in charge of all
intelligence matters and in close touch with the code-breakers
at FRUPsc; and he has stated that there was always great
concern'tivithin the US Navy that such vital information was
being passed to organisations outside their control.t"
Additionally, there was the constant problem of the US press
which was subject to far less severe censorship than the
British press and often published articles that came danger-
ously near to revealing the truth of such matters.
Because of the sensitive nature of the COIC summaries it
would have been normal procedure, as laid down by the New
Zealand Organisation for National Security, for them to be
distributed by hand, using a courier, as with similar material
from Bletchley Park. One of the great problems about putting
the ULTRA material to use was how to impart its information
without compromising the source. Frequently a cover story
would be invented to pretend that it had come from a spy.
According to a surviving officer from the Nankin,2' no such
courier mail was handed to Captain Stratford. It seems,
therefore, that the COIC summaries had been inadvertently
included with the general mail-which, considering the large
number of vessels captured by German raiders in the previous
two years. was an appalling breach oielementary security.
It has been possible to establish from two of Admiral Wen-
neker's telegrams to Berlin that COIC summaries 12. 13.
14. and 15 (covering the period 21 March to 211 April 1942)
were on board the Nankin and were captured. These particu-
lar reports were of crucial importance. They clearly showed
the increasing extent of the US Navy's knowledge of the
Japanese battle fleet's movements in the weeks leading up to
the Battle of Midway (3-5 June). and this could only have
come from reading the JN25 fleet-cipher.
U NLIKE THE Atiwomedon incident, on this occasion the
Germans fortunately took much longer to get the
mail to Japan. The Regensburg first called at
Batavia. on 25 June, and only reached Yokohama on 18 July.
Wenneker immediately examined the mail; on 20 July he
began relaying to OKM Berlin summaries of what he had
found in the mail, and on 25 July and 28 July2' sent details of
some of the COIC summaries. However, it was not until late
August that Berlin authorised Admiral Wenneker to show
the COIC reports to the Japanese. On 29 August he had his
'" Various conversations with John Costello (New York) during
1983 and 1984.
-" Captain B. W. Dun (Ret'd) (Hawthorn. Australia). 19 June
1984.
2' 1417/42 and 1435/42 gKdos (National Archives, Washington.
D.C.).
22 Imperial War Museum (London) and Public Record Office
(Kew). ADM 223/51 Part I.
'-' OKW/Abwehr I M/TB 1663/43 gKdos (18 August 1943).
Bundesarchiv (Freiburg).
=' John Costello. The Pacific War. pp. 246-49.
first meeting with them, and for the first time the Japanese
became aware of the extent to which the Americans were
reading their fleet ciphers and that this had obviously been
responsible for their severe defeat at the Battle of Midway.
Nevertheless, despite the evidence from the Nankin, senior
Japanese Naval commanders were very reluctant to believe
their most important cipher had in fact been compromised.
The Seekriegsleitung, the war diary kept at German Naval
Headquarters in Berlin, refers to this meeting (3 September
1942) arecords that the Allied knowledge of the Japanese
fleet 11I positions showed that their communications were
insecure, and the Japanese requested the assistance of the
German Navy in improving their cipher security. As a result a
communications agreement was prepared between the two
Navies (11 September 1942), and subsequently 500 Enigma
cipher-machines vuere sent to Japan from Germany in 1943.
German cooperation with the Japanese in the field of
cryptology had always been cautious because, in late 1940,
they had learnt that the Americans were reading Japanese
machine diplomatic ciphers-although. ironically, it never
occurred to them that their own Enigma system might also be
vulnerable=22
There was ample evidence available that Enigma had been
penetrated by the British, but, as so often in such matters.
Hitler's senior commanders refused to believe it and junior
German intelligence officers soon realised that it was /
pointless to try to convince them. In 1943, Colonel Masson of
the Swiss Secret Service had told German Intelligence" about
an American contact working in the Navy Department in
Washington. who had several times visited London with US
Navy missions. He had reported that the British Navy had a
special department (actually the Admiralty's Operational
Intelligence Centre) which since the outbreak of war had
concerned itself exclusively with the decipherment of German
naval codes-and, for some months past, had succccded in
reading all orders sent by the German Navy to U-boat
commanders. Despite this startlingly accurate piece of
information, the Germans continued to use Enigma, albeit
with a few extra refinements, and refused to believe that the
codes had been broken....
As a result of the disclosures from the captured Combined
Operations Intelligence Centre summaries, the Japanese
Navy immediately introduced strict new security arrange-
ments to protect the JN25 fleet cipher. It also drastically
reduced the volume of radio traffic. and made significant
changes to the call signs. The two code books used for JN25
were due to be replaced on 1 April 1942. as part of routine
procedure. Due to logistical problems in circulating the new
tables to every ship and shore station, however, the change
had to be postponed twice, and the fleet did not switch over
to the new cipher until 28 May.'' Between then and August
the US Navy's code-breakers began the laborious task of
reconstructing the new cipher tables. But immediately after
Admiral Wenneker's meeting with the Japanese on 29 August
they experienced a sudden signals blackout, so total that until
well into 1943 the US Navy was unable to obtain any useful
information.
This loss of signals intelligence seriously affected the
outcome of at least three major naval engagements in the
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The.Sinkinj; of the "Automedon", the capture of the "Nankin"
Pacific: the battle of Cape Esperance (11-12 October); Santa
Cruz (26 October); and Guadalcanal (13-15 November)-all
of which resulted in unexpectedly severe losses for the US
Navy.
The Americans were never told about the loss of COIC
material on the Nankin and how this compromised their code-
breaking achievements at one of the most important moments
of the war against Japan. To this day there is no mention of
the Nankin affair in any American archive-for the simple
reason that the British and Australian authorities have taken
great trouble to conceal the facts.
In 1945 the captured COIC summaries surfaced among the
German naval archives (exactly where they were found is not
clear, but it may have been at Schloss Tambach). By the time
the German records were repatriated to Bonn in 1958. all
reference to the Nankin affair had been removed. The log of
the raider Thor (which is now in the Bundesarchiv at
Freiburg) appears to have been retyped since the War." The
entry concerning the Nankin's capture makes no reference to
any mail having been found on board; yet, a week earlier, the
entry for the capture of the Norwegian tanker Aust precisely
details the mail and other documents taken from her.
THE MOST CURIOUS ASPECT, indeed the greatest mystery,
of the whole affair is the missing portion of Admiral
Wenneker's war diary for-the period 1 June through
31 October 1942. This just happens to include the period
when the,(Vankin's mail reached Japan, and Wenneker had
his series-of meetings with the Japanese Naval Command.
According to the Naval Historical Branch in London, this
section was lost in transit between Tokyo and Berlin-
although the rest of his diary (from 25 August 1939 through
31 March 1943) is intact and available." The absence of this
section of his diary makes it impossible to know what else
Wenneker found among the Nankin's mail, what he told
Berlin about it, and what was discussed at his meetings with
25 1 am grateful to Dr John Chapman, University of Sussex. for
information supplied. I would also like to thank John Costello (New
York). Philip Reed (The Imperial War Museum), [an Brown
(Combined Services Records), Michael Montgomery. the late
Ronald Lewin. M. McAloon and R. M. Coppock (Naval Historical
Branch. Ministry of Defence), and Ellen Ellis (New Zealand
National Archives) for their valuable comments and assistance in
preparing this article. I am greatly indebted to Dr Henry Kent for his
expert translation of many of the German documents involved.
'' Paul Wenneker's diary, under the title The Price of Admiralty.
has been edited and translated by John W. M. Chapman (Saltire
Press. 1984).
the Japanese. From checking the serial numbers of
Wenneker's telegrams one can deduce that between 20-28
July 1942 he sent 52 messages to Berlin, most of which were
probably about the Nankin's mail. The incoming-signal log at
German Naval Headquarters in Berlin (in which all
Wenneker's messages would have been recorded) has also
vanished.
Wenneker's signals to and from Berlin after Hitler's
invasion of Russia in June 1941 went by direct-beam radio,
and were intercepted by the British code-breakers at
Bletchley Park; they called this material Seahorse.
Wenneker's special Enigma key (it is possible he was using an
8-r rr machine vastly more complex than the normal 4-rotor
machines) was not broken by Bletchley Park until late 1943.
At the end of the War, his earlier traffic would have been
retrospectively decoded (as the Americans did, for example,
with the Japanese Naval Attache's signals from Berlin).
Today, Wenneker's messages are kept in the "Japanese
ULTRA Intercept" archives, under the control of the Foreign
Office, which will not release them to the Public Record
Office. When I was carrying out research for this article, I
asked the Foreign Secretary. Sir Geoffrey Howe, if I could
see the 50 or 60 messages sent to Berlin by Admiral
Wenneker in July/August 1942; 1 was not only refused access
but also informed that none of this traffic would ever be
available for public inspection. It is just possible that the US
National Security Agency may hold copies of Wenneker's
signals among its as yet unreleased archives, without realising
that they contain the information that proved so'disastrous v
for the US Navy in 1942.
HAD DETAILS of the COIC mail from the Nankin reached
Japan more quickly there is no doubt that the outcome of
the Battle of Midway would have been very different. All
historians agree that the American victory turned the tide of
the Pacific war and set the United States on the road to
ultimate victory. The decisive victory very largely resulted
from the US Navy's ability to read the Japanese Navy's
ciphers and thus anticipate their intentions. As it was, the loss
of this material seriously reduced the US Navy's fighting
ability for many months at a most crucial point in the War,
and caused unnecessarily severe American losses in several
subsequent naval battles.
Just as the proverbial battle can be lost by "want of a nail"
in the horse's shoe, so too the events of the Automedon and
the Nankin illustrate that the most complex cipher system in
the world. taken to be infallible or unbreakable, can be
compromised by an accident, a far-away setback, or a single
moment of carelessness.
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 JITCOU1ITTII
MAY 1985 VOL LXIV No. 5 ISSN 0013-7073
CONTENTS
The Changeling (stogy) A. S. Byatt 3
STAT
The inking of the "Automedon",
the Capture of the "Nankin" ,James?usbridger 8V
Gutenberg & the Computer Daniel Bell 15
Column M 21
POEMS
Ruth Silcock 23, John Lancaster 24, Frank Ormsby 25, John Loveday, 36,
Robert Giui gs 74, Kim Baker 78
NOTES & TOPICS
The Candle of Dresden Edward Pearce 26
Of Secrecy & Intelligence Robert Cecil 28
A Polish Murder Trial Leopold Labedz 32
Paris Notebook Jean-Francois Revel 33
t
d
BOOKS & WRITERS
Interpreting the Past Joan Aiken 37
Whig Blank Verse & Tory Couplets W. W. Robson 43
Uncommonplace Books Gavin Ewart 50
Books Encountered R.M. 53
EAST & WEST
This Spy Business H. S. Ferns 54
POINTS OF THE COMPASS
Traveller in Albania Paul Lendvai 62
LANGUAGE
"A Clear Provocation" Werner Cohn 75
BOXES
The Mole Hunt (Chapman Pincher) 29, Tapping Wires (Bernard Levin) 31, "Security"
(Christopher Leake) 55, "Sedentary Intellectuals?" (Peter Hennessy) 57, Obscure Plaintext?
(Fames Rusbridger) 59, Welcome Disgrace (Peter Simple) 60, "Poppycock" (Reuters) 64,
Gold Fingers (New York Times) 67, Eagles & Stars (The Times/Amnesty International) 70,
Stalin's Black Magic (Michael Trend) 73, Definitions (Nigel Wade) 76, Russlish
(The Times) 77
LETTERS..... AUTHORS.._. LIFE & LETTERS
79 20 81
August and Septtnlber.Oct bey am sings inum1. Par copy: UK ri CA. Frew 11 5.. .. __ _ _
..
e
Inaia ?20.00 by atr. Elsewhere ?19.00.
I Martn,'s Lane, Londe. WC2N 47S (01436 4194): UK Trade Dismharen? rd?r... All c. 9-L_
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