From: U.S. Congress Joint Committee on Pearl Harbor Attack Hearings; Pt.
35, the Clausen Investigation, pp. 62-81.
 Exhibit "A"
U. S. PACIFIC FLEET RADIO UNIT
Box 103-Navy Yard, Navy Number 128 One Two Eight, c/o Fleet Post Office,
San Francisco, Calif.
18 APRIL 1945.
Received from Officer-in-Charge U. S. Pacific Fleet Radio Unit 42 pages
covering daily communication intelligence summaries for the period 1
November 1941 through 6 December 1941.
Select a date to view, or scroll through the file:
1 November 7 November 13 November 19 November 25 November 1 December
2 November 8 November 14 November 20 November 26 November 2 December
3 November 9 November 15 November 21 November 27 November 3 December
4 November 10 November 16 November 22 November 28 November 4 December
5 November 11 November 17 November 23 November 29 November 5 December
6 November 12 November 18 November 24 November 30 November 6 December
 Communication intelligence summary, 1 November 1941
General.-Traffic volume a little less than normal, receiving conditions
fair but a traffic rather slow. The first day’s yield of new calls not
very great. Fleet calls only changed, shore station calls and shore
addresses not changed. It is believed that tactical calls also remain
unchanged but not enough intercepted traffic to so state definitely. The
same garble table for calls is employed so the change amounts to a
reassignment of calls previously used. New calls have appeared but it is
thought that they were formerly assigned to obscure units or were in
reserve. All of the major Fleet calls are identified and a small amount
of individual calls were recovered today. Because the new calls are not
yet lined up save for the major Fleet Commanders and all time today was
spent in call recovery, this summary will deal only with general
Combined Fleet.-The FIRST FLEET was not very active today in radio
traffic. The CINC SECOND FLEET appears to have originated quite a bit of
traffic to addresses placed in submarine and carrier category. No
indications of movement of any of these units. COMBINED FLEET tactical
circuits were heard but little tactical traffic copied due to
interference by NPM.
Carriers-The COMMANDER CARDIVS was mentioned in dispatches from Tokyo
and he took a fair amount of traffic on the Fleet Broadcast.
Submarines.-Nothing to report. Calls of the Submarine Fleet not well
lined up yet.
Third Fleet.-This Fleet very active as before. The SECOND and FIRST BASE
FORCEs are still marshaling their MARUs and the CINC is very busy with
China.-The activity of HAINAN BASE continues. The KASHII sent several
messages from Saigon.
 Communication intelligence summary, 2 November, 1941
General.-Traffic volume normal for Sunday. Receiving conditions were
fair but bulk of traffic derived from the major shore circuits. Solution
of new call system progressing satisfactorily but volume of accumulated
traffic in new system not yet large enough to permit more than casual
identification of individual calls. The number of alternate calls for
major commands is increased over last system. So far there are seven
alternate calls for the Combined Fleet.
Third Fleet traffic is still on a very high level. The combined air
Force traffic is also very high with the Commander of the Combined Air
Force originating many dispatches. It appears that he is now in Taiwan.
Traffic to SAMA and BAKO is on a very high level. Tokyo and The China
Fleet Intelligence bureaus are originating periodic dispatches, these
from Tokyo being prefixed WIWI. There were several high precedence
dispatches from Tokyo with the major fleet commanders as addressees.
 Communication Intelligence Summary, 3 November 1941
General.-Traffic volume slightly under normal although fair for Monday.
Receiving conditions good but all circuits slow. General messages
continue to emanate from TOKYO communications. Such an amount is
unprecedented and the import is not understood. A mere call change does
not account for activities of this nature. The impression is strong that
these messages are periodic reports to the Major Commander of a certain
nature. Dummy traffic is again being sent in the TOKYO broadcasts. Naval
Intelligence TOKYO addressed two WIWI messages to Chief of Staff
Combined Fleet and to KUMI 8 (unidentified).
Combined Fleet.-Commander in Chief Combined Fleet sent an urgent message
to BUMIL information all Major Commanders, Combined Fleet, Naval
Intelligence Tokyo, the Chief of Naval General Staff, and Bureau of
Personnel. Commander in Chief, Combined Fleet also was associated in
traffic with offices in the mandates. principally RNO PALAO. The
Commander in Chief, Combined continues to be associated with the
Carriers and Submarines.
Third Fleet.-Third Fleet traffic continues at a high level. A movement
report by RATI 66 (unidentified) was addressed to Commander in Chief
Third fleet for information.
Air.-A WE address today broke down as "ITIKOUKUU KANTAI". The literal
reading of this as "1st Air Fleet" is correct it indicates an entirely
new organization of the Naval Air Forces. There are other points which
indicate that this may be the case. An old call (YOME7) while never
identified seemed to be in a high position with respect to the Carriers
and the Air Corps. Upon movement of air units to TAIWAN the association
of CarDiv 4 and CarDiv 3 with units of the Combined Air Force was
apparent. Their association in a command sense between shore based air
and fleet air had never occurred before but under the concept of an AIR
FLEET can easily be accepted. Traffic in the Air Force continues at a
 Communication Intelligence Summary, 4 November 1941
General.-Traffic volume normal with all circuits easily readable. More
tactical traffic copied than for past few days. Combined Fleet and
Carriers heard on tactical circuits. TOKYO Naval Intelligence sent four
messages to Major Commanders. One of these was for information Chief of
Staff China Fleet and one other for information of Chief of Staff Second
Air-High traffic level of air activities continues. Most significant of
the air dispatches were some in which various air corps were addressed
and BAKO included for information. One from Yokosuka Air was addressed
to SANCHOW Island radio for information TAKAO Air Corps. BAKO was also
noted as an addressee in several messages from SASEBO and originated two
messages to SASEBO and TOKYO. Commander Carriers also addressed a
message to two unidentified calls for information of Commander Combined
Air Force, Commander in Chief, Combined Fleet, CarDiv Collective, BAKO
and others. The Commander Combined Air Force addressed a messaged to
Commander in Chief Third Fleet.
Mandates.-The RNO PALAO was active today, being addressed by Commander
in Chief, Fourth Fleet and sent several messages to TOKYO and YOKOSUKA.
The PALOA weather station sent a long code message addressed to nearly
all the islands of the Mandates. MARCUS island appears as an originator.
No change in the location of Fourth Fleet units noted.
Submarines.-No activity noted.
 Communication Intelligence Summary, 5 November 1941
General.-Traffic volume above normal. All circuits heard and receiving
conditions were fair to good. TOKYO very active as an originator,
sending out many messages of general address. Two WIWI messages in Kana
Code sent by NGS to Chief of Staff CarDivs and TIYA 44 (unidentified)
respectively. The Intelligence Offices of China Fleet and TOKYO continue
active with many dispatches passing between the two.
Third Fleet.-Two units of the Third Fleet appear today in TAKAO area.
Since these calls are as yet unidentified (RISI4 and YOA2) it is not
known how much of this fleet they represent. It is fairly certain that
the Commander in Chief, Third Fleet has not yet left the Sasebo area
although it is expected that he will before long. One message which may
be a movement report from him was received late on the 5th. The present
state of call recovery on the Third Fleet does not permit of an estimate
of the movement involved.
A unit of the First Fleet, identified today as CARDIV 4 appeared today
at BAKO. This Carrier Division was addressed as "less FUTA SHOTAI" (2nd
Section?) Whether or not these are other units at BAKO is not known. The
Commander CARDIVS has been associated with SAMA and BAKO in several
dispatches today. The following were also associated, SANCHOW ISLAND,
TAKAO AIRCORPS, CANTON (China) and YOKOHAMA Air. The RNO TAIHOKU
originated many dispatches to TOKYO and the French Indo China Forces. A
TAIWAN originator sent one to Lieut. Comdr. SHIBA at the Embassy
THAILAND for information to HANOI and the Commander French Indo China
BAKO originated numerous dispatches to the Empire and to the Major Fleet
The South China Fleet was also the recipient of many dispatches from
Despite the uncertainty due to the Change of Calls it is believed that
there is now being effected a concentration of naval forces in the BAKO
area which will comprise the Third Fleet as organized in SASEBO for the
past month and will be augmented by heavy air forces and Combined Fleet
units to an unknown extent.
 Communication Intelligence Summary, 6 November, 1941
General.-Traffic volume slightly above normal. Receiving conditions were
fair, regular strong but heavy static on night watches interfered
somewhat. Today the specific call-up on the Tokyo broadcast was
eliminated. Formerly Tokyo radio called the unit concerned when the
dispatch was addressed to a member of that unit. Beginning yesterday
afternoon all broadcast messages are addressed to a single call without
regard to the addressee of the message. The recovery of the radio
organization will be hampered by this new advance in Communication
Security. Moreover there were nine messages today on this broadcast from
which the address and originator were missing. This may be the start of
complete elimination of headings on broadcast circuits. Tokyo addressed
a WIWI message to the Chiefs of Staff of the Combined Fleet and
Takao-Bako Area.-It is now certain that there is a very heavy air
concentration on Taiwan. This comprises practically the entire Combined
Air Force including the Commander and his staff plus at least one
carrier division and an unknown amount of the fleet air arm. No
additional units of the Third Fleet were located there today but it is
believed that CinC Third Fleet is now en route BAKO from SASEBO. From
traffic association it is believed that some Second Fleet units are in
Takao area but this has not yet been proven. The South China Fleet
Command has been active in dispatches to Taiwan addresses.
Combined Fleet.-A large amount of Combined Fleet traffic is now
appearing with secret (tactical) calls in use.
Mandates.-The Mandates traffic has dropped off somewhat. The Sixth
Defense Force at Truk and the RNO PALOA continue to be the most active
 Communication Intelligence Summary, 7 November, 1941
General.-Volume of intercepted traffic larger than usual. Due to the use
of the general call "All Major Force Flags" on the UTU for delivery to
all Combined Fleet units, affiliation of unidentified calls with forces
to which at-
tached is very difficult. Use of large number of alternate calls for
major fleet forces, many of which have not yet been definitely
identified or associated with known calls, renders the picture more
confusing. Appearance of the prefix "JITSU" (authenticator for bona fide
traffic) in several messages indicates that a communication drill is
being held but without indication as to what units are participating and
therefore much of the traffic is suspected of being "drill." Jaluit
Radio is handling traffic direct with Yokosuka Radio probably due to
congestion of Mandate circuits from the Marshalls caused by heavy
concentrations in that area.
Air.-Continued high traffic level for all classes of air activities,
mainly centered in the Taiwan area, but also with all air activities in
the Mandates included in headings of messages. Dispatches originated by
Fourth Fleet Command included Air Forces, Base Forces, Air Stations, and
all types of Mandate activities in long headings.
Fleet.-Fourth Fleet Command remains in Truk area. There are indications
that portions of the First Fleet may be moving to the Takao area but
identifications are not sufficiently certain to confirm this.
Greatest effort is being made to increase the number of identified calls
to facilitate analysis of the traffic but Orange changes in methods of
handling fleet traffic renders this more difficult than had been hoped.
 Communication Intelligence Summary, 8 November 1941
General.-Normal volume of intercepted traffic with no "dummies"
appearing on the UTU. All UTU traffic was broadcast to the general call
only. The Staff Communication Officer of the French Indo-China Force
(So. Exp. For.) sent a dispatch *action* to S. C. O. Combined INFO. S.
C. O. Second Fleet, Combined Air Force, unidentified fleet unit, Radio
stations at Tokyo, Palao and Takao. This may indicate a contemplated
coordination of communications between the Indo-China-South China areas
and the Palao Island-Taiwan area. Secret calls were used very little as
compared to the past few days and only three circuits were heard using
them, including the Combined Fleet Commanders circuit and Air Station
Net. North Japan-Ominato circuits were quiet. All mandate circuits were
active, with heavy interchange of traffic involving all classes of
Mandate addressees in all areas, but with continued emphasis on the
Palao area at one end d the Jaluit-Marshall area on the other.
Chichijima Air Station was included much of the traffic between Empire
Offices and Saipan Air with Jaluit Base Force included for information.
Inclusion of Chichijima usually presages an air movement between
Mandates and Empire but the Units involved are unidentified. Commander
of unidentified shore activity (NEO 66) previously associated with the
Fifth Fleet, was addressed at Chichijima Air which tentatively
identifies him an air activity. Previous association of the Fifth Fleet
traffic with Fourth Fleet and Yokosuka tends to confirm the belief that
Fifth Fleet operations are, or will be, in the area adjacent to
Chichijima-Marcus, supplementing the Fourth Fleet in the lower island
Fleet.-Chief of staff First Fleet originated a dispatch through Kure
Radio. Batdiv Three of the First Fleet appears to be operating
separately from the main force, possibly in connection with Cardivs
Three and Four in the Taiwan-Naha ea. An apparent movement report from
Cardiv Four was addressed to CinC Combined Fleet, First Fleet, CarDiv
Commander, Combined Air Force Commander d to movement offices at Tokyo,
Yokosuka, Kure, Maizuru, and Sasebo. Traffic from the Commander Indo-
China Force is handled from the Japanese radio station Saigon rather
than from the KASHII, indicating that the staff is based ashore present.
No identifiable submarine activity was noted.
Air.-Takao and Mandates continue to be the center of air activities. The
area between Chichijima, Naha, Takao, Palao and Jaluit appears to-be
particularly concerned with movement of air forces and auxiliaries,
while the formation of force under Combined Air Commander in the Takao-
Bako area appears to be nearly completed as indicated by reports
addressed to CinC. Combined, Naval Minister, Commanders of CarDivs,
Combined Air Force, First  Fleet and shore addresses generally
associated with movements or organization changes. This force is
believed to include CarDiv Four, and possibly CarDiv Three, with a
number of auxiliaries and units of the Combined Air Force, also possibly
some its from the First Fleet. Lack of identification renders
composition of the force highly speculative and area of operations
obscure. Prior to change of calls, much traffic was exchanged between
China, South China and Indo-China while at present most traffic includes
 Communication Intelligence Summary, 9 November, 1941
General. Traffic volume heavy for Sunday. Receiving conditions fair but
heavy static caused numerous garbles and fragmentary messages. Navy
Minister sent several messages of general address including one to all
First and Second Class Naval Stations. Practically all of the general
messages carried SAMA as an information address. Carrier Division Three
arrived at Takao and there are indications that Carrier Division Four
will return to Sasebo from Takao. The Flagship of Carrier Divisions is
AKAGI and is in Sasebo area. Some tactical traffic today shows units of
Combined Fleet still operating. The associations of Batdiv Three and
Mandate addresses, especially Saipan may indicate operations of that
unit in the Mariannas. The JINGEI was communicating with SAMA, HAINAN
today. The Chief of Staff of the French-Indo China Force is in Tokyo.
One message today addressed to CinC. Combined Fleet was routed to
MAIZURU for delivery but this is believed a communication error. The
Third Fleet appears to be still in Sasebo area but it was noted that
considerable traffic passed between Hainan, Taiwan addresses and the
Third Fleet. The Fifth Fleet is still being organized with no
indications yet that it has assembled. The Eighteenth Air Corps at
Saipan originated much traffic to Yokosuka Air Corps.
 Communication Intelligence Summary, 10 November, 1941
General.-Traffic volume normal, receiving conditions good. There were
fewer general messages sent today than for the past few weeks. Tokyo
Intelligence still active and addressing dispatches to all Major
Commanders. The Mandates construction traffic has decreased
considerably. Call recovery is progressing but has been slowed down by
the general call-up used on Fleet broadcast.
Combined Fleet.-Believed to be mostly in Kure area. A staff officer of
Batdiv Three was addressed there today and it is likely that this whole
division is there also. The CinC. Second Fleet was located at Kure today
as well as two cruiser divisions.
Third Fleet.-The greater portions of this fleet still in Sasebo area.
Several movement reports have been noted by units of this fleet but none
have been noted other than individual ships. At least two units of this
fleet still at Takao. CinC Three originated one movement report for
information of CinC Fourth Fleet.
Fourth Fleet.-Little activity. CinC. Fourth remains in vicinity of Truk
with major portion of his command. The Staff Communication Officer of
Submarine force sent a message to the CinC Fourth for information of
Fifth Fleet.-One unit of this fleet located at Chichijima.
Air.-The Combined Air Force Command is still talking to Sama and the
South China Fleet. From one address it appears that the Commander of
Carrier Division Three is with the Combined Fleet. Several units of the
Carrier Divisions are in port at Kure and Sasebo. CinC Combined Air
Force is still in Takao.
[No entry for November 11th, LWJ]
 Communication Intelligence Summary, 12 November 1941
General.-Traffic volume normal for past two days with receiving
condition about average. The general character of the traffic has been
administrative With most of it being between shore logistic and
technical activities. The D. F. net was active today with very little
activity shown yesterday. Intercept operators have commented adversely
on the major shore network which comprises all of the major naval
activities in the EMPIRE. Traffic has been moving slowly over this
circuit. The reason is the non-cooperation of the operators and the
definite lack of control exercised by TOKYO radio stations. TOKYO
Intelligence is still sending messages to the major commands but the
remainder of TOKYO traffic has been mostly from the technical bureaus.
Combined Fleet.-The Fleets remain relatively inactive in the KURE area
The association of BATDIV 3 with the Fourth Fleet and several Mandates
stations is born out by a D. F. position on the flagship of BATDIV 3
which places him about halfway between CHICHIJIMA and MARCUS Island.
Their position was obtained on the 4th when this unit was not yet
identified. No subsequent bearings have been obtained. Also associated
with this BATDIV are a Submarine Squadron and possibly CARDIV 4 although
the association of this CARDIV (Lately returned from TAKAO) is not
positive. The Third Fleet remains at SASEBO with the only activity
exhibited in the Base Forces.
Air.-CARDIV 3 returned to KURE from TAKAO as reported by CAVITE. Most of
air activity confined to dispatches between carrier and shore
Fifth Fleet.-Nothing to report.
Fourth Fleet.-The Defense Forces of the Mandates fairly active. The
volume of construction traffic has definitely fallen off. The Commander
Submarine Force is still adding JALUIT and today COMSUBRON 2 addressed a
message there. AIRRON 24 sent a movement report but no indication of the
direction. Communication exercises were held by JALUIT and several
stations in that area. YOKOHAMA Air Corps was addressed at RUOTTO.
China.-The previous activity of SAMA and the French Indo China Forces
and bases continues.
 Communication Intelligence Summary, 13 November 1941.
General.-Traffic volume normal with receiving conditions good. Several
messages of high precedence intercepted, some of them are:
1. UNIWIWI dispatch in five numeral from TOKYO Intelligence to Chief
of Staff Combined-Air Force, INFO RNO TAIHOKU, BAKO Naval Station.
2. WIWI from N. G. S. to MAIZURU INFO Chief of Staff Fourth Fleet.
3. NIKAWIWI from N. G. S. to Commander in Chief Combined Fleet INFO
Commander in Chief South China Fleet, Commander Third Fleet and
4. UNIWIWI from N. G. S. to Secretary First Fleet.
5. (2 messages) WIWI to same address as 3 above.
6. A 3 part NIKAWIWI from N. G. S. to Commander in Chief Combined
Fleet, INFO Commander in Chief French Indo China Fleet.
7. One UNI message from Commander in Chief China Fleet to SAMA, INFO
Commander in Chief Third Fleet and Commander in Chief Combined
This is the only occurrence in some time of anyone save the TOKYO
intelligence activity using the WIWI prefix. Both TOKYO and the China
Fleet Intelligence Bureau were active all day with dispatches to the
The direction finder net was again active all day with CHINKAI, ORU 7
(near CHINKAI), JALUIT, SAIPAN, and TAIWAN sending in bearing reports.
Combined Fleet.-The activity of BATDIV 3 is not clear. The flagship is
operating and was located by D. F. as reported yesterday. The Commander
of BATDIV 3 is located in YOKOSUKA. The Division Communication Officer
is communicating with TRUK, SAIPAN and PALAO. The other ships in this
division remain unlocated but it is assumed, lacking evidence to the
contrary, that they are with the flagship. Other units of First Fleet
seem inactive. One Cruiser Division of Second Fleet is associated in
traffic with PALAO and may be in that area.
Third Fleet.-Still located in SASEBO, the Commander in Chief has been
active in the traffic, being addressed by both TOKYO and Commander in
Chief Combined Fleet. The First BASE FORCE Commander originated several
messages but no indication of change of location.
Fourth Fleet.-The Commander in Chief Fourth Fleet is in communication
with he Sixth BASEFORCE JALUIT. Several message were exchanged. He
appears o be preparing for a move from TRUK but no movement has yet
occurred. SUBRON 2 is again in communication with JALUIT and today
originated a movement report, but no indication of direction.
 Air.-Carriers remain relatively inactive. The SETTSU is still
with them and a few may be engaged in target practice near KURE. The
Combined AIRFORCE is still mostly located in TAIWAN and the usual high
traffic level between its component Air Corps still exists.
China.-The Commander in Chief China Fleet was addressed in one of the
RNO TAIHOKU. His Chief of Staff is still in SHANGHAI.
 Communication Intelligence Summary, 14 November 1941
General.-Traffic volume a little under normal due to poor to fair
receiving conditions throughout the day. The Naval Ministry originated
several AlNav dispatches. There were three WIWI messages originated
1. UNIWIWI from N. G. S. and BUMIL to Chief of Staff Fourth Fleet
information Chief of Staff Combined Fleet and YOKOSUKA.
2. WIWI from N. G. S. and BUMIL to Chief of Staff Combined Fleet,
Chief of Staff Third Fleet, YOKOSUKA and SASEBO.
3. UNIWIWI from N. G. S. to ANI758 (Chief of Staff of an unidentified
unit), Information Chief of Staff Combined Fleet and Chief of
Staff Combined Air Force.
Direction Finder Net active with SASEBO station sending in bearings in
addition to the others. Tactical circuits heard during day with a fair
amount of activity.
Combined Fleet.-Little activity noted. The flagship of BatDiv Three is
still operating but no further information on this division. Two
Combined Fleet units appear active in the traffic. They are DesRon Three
(normally in First Fleet but has been operating with Second Fleet) and
CruDiv Seven of Second Fleet. Both of these units have been associated
in traffic with the South China Fleet and the French Indo China Force.
They may proceed to the South China area in near future.
Third Fleet.-Still in Sasebo area. The CinC. has been addressed by Tokyo
to a great extent and is still associated with South China activities in
traffic. It has been noted that the association between the Third Fleet
and units of the Combined Air Force is growing. Especially the Second
Base Force has been talking with several Air Corps among whom is the
Kure Air Corps. Will air units be embarked in ships of the Base Force?
Fourth Fleet.-No movement yet from the TRUK area. It appears that the
Fourth Fleet Staff is fairly well split up. Various officers of the
staff were addressed at Tokyo and at unidentified locations.
Submarines.-No particular activity. One unit evidently enroute PALAO and
Submarine Squadron Two (now in Kure area) still being addressed by Tokyo
and Yokosuka originators.
Air.-One Air Squadron of the Combined Air Force is at HOIHOW, HAINAN.
The Commander of the Air Force is still at TAKAO with a good
representation of his command. The Carriers remain in home waters with
most of them in port.
 Communication Intelligence Summary, 15 November 1941
General.-Traffic volume normal, with a number of general address
messages originated by Communication Division, Tokyo, to Radio Officers,
Ominato, U. E. 9 (D. F. Station in Marshalls), Jaluit, Palao, Truk,
Saipan, Takao and Sama Radios, Staff Communication Officers All Major
Flagships, Staff Communication Officer South Expeditionary Force and two
apparent collective shore addresses. Traffic from all stations mentioned
except Sama and Ominato to D. F. Control and Plotting Room Tokyo
information to Staff Communication Officer Combined Fleet was exchanged.
No messages of the D. F. type were detected so it is presumed that the
interchange had to do with arrangements for drill or organization of the
net. The Minister of the Navy originated one Alnav and one to all Major
Commands and collective shore. Tokyo Personnel and Tokyo Communication
Division originated several to collective fleet and shore. Significance
is not determined though it is believed possible that a further partial
change of shore and air calls may be in prospect. The Empire air station
net was normally active using tactical calls. Secretary First Fleet I
originated one Urgent Code to unidentified (MINI 55), Staff
Communication Officer Carrier Division Four (at Sasebo) and Commanding
Officer of Batdiv Three flagship.
Combined Fleet.-Same as yesterday, same units (Batdiv Three, Desrons One
and Three) associated through traffic with South Expeditionary Force.
CinC Second Fleet was the most active originator and appeared to be
arranging operations of units involving First, Second, Carrier and Air
Fourth Fleet.-Apparent movement of Fourth Fleet units in prospect or
underway with continued emphasis on the Marshalls Area. CinC. Fourth
traffic still being handled from the Truk area, with Airron Twenty-four
(Kamoi) and associated Yokohama and Chitose air units involved in some
movement direction undetermined. All Marshall Island activities,
including unidentified Army Forces, exchanging traffic freely.
Submarine Force.-Little activity detected. It is believed that some
submarine activity is operating or preparing to operate in the Marshall
area, from communication arrangements underway between Staff
Submarine Force and same Fourth Fleet, information to Jaluit. Jaluit has
been heard working on various frequencies, using tactical calls and
procedure associated with submarine operations, but no identifications
of calls used have been made.
 Communication Intelligence Summary, 15 November 1941
Air.-Continued air traffic to and from Takao area, with unidentified
Airron formerly YOME 7) including South Expeditionary Force and Sama
addressees n traffic. Composition of this force and purpose still
speculative but believed o be preparing to move southward to work with
the South Expeditionary Force.
The large number of alternate calls used by major forces renders
analysis of traffic headings very slow and difficult, but
identifications and recoveries of alternates are improving as a greater
volume of November traffic becomes available for research.
 Communication Intelligence Summary, 16 November 1941
GENERAL.-Traffic volume approximately normal for week-end period. A new
form of dispatch heading appeared in a series of dispatches broadcasted
on the regular UTSU series. Only the originator or the address of the
dispatch appeared; it is assumed that the other pertinent call or
address may be buried n the text. These dispatches were with one
exception (in 5 numeral text) all a the nine-Kana period separator
system and the single call in the heading fitted in each case Line seven
of the call garble table.
A dispatch was originated by the Navy Minister addressed to all Major
Fleets and general addresses to this effect:
"Today the House of Peers and House of Representatives by means of a
decision adopted the following resolution transmitted as follows:
1. Resolution of House of Peers-(Expressed deepest thanks and emotion
to Army and Navy for their glorious service over a long period to the
Empire and expressed condolences, etc., for those fallen in battle.
2. Resolution of House of Representatives-Expressed thanks, etc., to
all officers and men of Army, Navy and Air Force for their 4 1/2
years service (in China affair) and for their contribution to the
establishment of a permanent world peace. Gave prayers for well being
of all hands, etc. ."
First and Second Fleets.-Majority of First and Second Fleet Units remain
in the general Kure area. The units of these two fleets that have been
most active from dispatch heading viewpoint in the last ten days appear
Airon Seven (3 Chitose class)
Carrier Division Four
Destroyer Squadron Seven
Destroyer Squadron Three
Battleship Division Three
Cruiser Division Seven.
It is rather singular that the CinC. Second Fleet has assumed an
important role in addressing for action several first fleet and other
fleet units recently. In some of these dispatches the call identified as
Southern Expeditionary Force (Indochina Force) appears. Associations of
addresses in several dispatches have shown the Second and Third Fleets
with the Combined Air Force and in other dispatches, there appears to be
an association between First Fleet, Carrier Divisions and the Mandates.
 It is apparent that Destroyer Squadron One has been or is
operating with the Carrier Divisions and Battleship Division Three while
Cruiser Division Seven and Destroyer Squadron Three have been operating
together. Iwakuin [sic] Air sent short priority dispatch to the ATAGO,
Second Fleet cruiser and submarine units indicating some joint minor
exercises in that area.
Third Fleet.-Believed inactive in Sasebo-Kure area.
Fourth Fleet.-FUATU, a Tokyo address originated one UNI dispatch to an
unidentified fleet unit (MEN 33), information to CinC. Combined Fleet,
Communication Officer, Fourth Fleet, Saipan Base Force, Kure Movement
Officer, CinC. Fifth Fleet, Tokyo Intelligence, and NEO 66, believed to
be a shore based air activity in Chichijima-Marcus area.
Fifth Fleet.-Prior to the change of calls on 1 November, the composition
of the Fifth Fleet was very indefinite but appeared to contain several
naval auxiliary type vessels. Since 1 November, little has been
recovered of the com-
position of this mythical fleet but it is definite that some units are
operating in the general Yokosuka Chichijima-Marcus.
Submarines.-Little activity. Communication Officer, Submarine Force
originated one priority dispatch to unidentified address, information to
Combined Fleet Communication Officer. Association of Submarine Force and
Fourth Fleet Commands continues.
 Communications Intelligence Summary, 17 November, 1941
General.-Traffic volume normal with receiving conditions good. More
traffic with single call heading appeared on the broadcast circuit.
These dispatches numbered serially and each call different but all
fitting the same line in the call garble table. Since these messages are
transmitted each hour on the hour and are of approximately the same
length it appears that they are drill messages. It is feared that they
constitute a test of straight broadcasting without a heading. Since none
of this traffic has been found going in to Tokyo it is probably
originated in the Navy Ministry. Very few messages of general address
were noted. Tactical circuits in the Mandates were heard during the day
with radio Saipan controlling.
Combined Fleet.-No movement from the Kure area of any major portion of
the First or Second Fleets. The CinC. Second Fleet very active as an
originator today. He continues to address units which are most normally
under his command. He also addressed the CinC. Third Fleet, Paloa
Forces, and the Chief of Staff Fourth Fleet.
Third Fleet.-Inactive at Sasebo. The Staff Communication Officer of
Third Fleet was addressed by the R. N. O. Paloa.
Fourth Fleet.-The greater part of the activity in the Mandate area
centered about the Third Base Force at Palao and the Sixth Base Force at
Jaluit. Both these activities originated traffic.
Air.-The Commander of the Combined Air Force remains in Takao and was
addressed frequently by SAMA, HAINAN and was in two instances addressed
by the Fourth Fleet. The carriers are mostly in the Kure-Sasebo area
with the exception of a few which are operating in the Kyushu area.
China.-Sama was again active today with dispatches to the Combined Fleet
Staff, Combined Air Force, Third Fleet and Bako. The R. N. O. Taimoku
addressed a dispatch to CinC. China, Sanchow Island Sama, Bako, CinC.
South China, and Chief of Staff Combined Air Force.
 Communications Intelligence Summary, 18 November 1941
General.-Traffic volume a little under normal with receiving conditions
fair to poor. Tokyo originators active with several messages of general
address emanating from the Communication Section. The double originator
BUMIL, and N. G. S. sent one NIKAWIWI to the Chief of Staff Combined
Fleet for information to all First Class Naval Stations. BUMIL also
addressed all urgent dispatch to SAMA, information to R. N. O. TONIC,
Chief of Staff South China Fleet and Chief of Staff Combined Fleet.
Another Tokyo originator, believed to be N. G. S., sent an urgent
message to Chief of Staff Combined Fleet, Chief of Staff French Indo
China Force and Chief of Staff Second Fleet. MAIZURU Naval Station also
sent an urgent message to Chief of Staff Combined Fleet, Second Fleet,
Combined Air Force, French Indo China Force and for information to N. G.
S. The Tokyo Direction Finder plotting section sent three long
dispatches to the entire Direction Finder Net which was very active
today with many bearings reported. The Vice Chief Naval General Staff
sent one to Chief of Staff Carrier Divisions and Chief of Staff French
Indo China Force.
Combined Fleet.-CinC. Combined Fleet very prominent as both an
originator and addressee. Since this officer is always included in the
address of every important message, he will no longer be mentioned as an
addressee unless he is the only addressee. The association between the
CinC Second Fleet and the French Indo China Forces and Combined Air
Force is very plain. He was addressed by CinC. French Indo China Force
today in an urgent NIKA dispatch. Several units of the Combined Air
Force also addressed several dispatches to him. Battleship Division
Three the Carrier Divisions and two destroyer squadrons have been
associated in traffic. Several dispatches occurred today, being
addressed by N. G. S. and the Commander Carrier Divisions in several
instances. The CinC. Third Fleet also addressed several dispatches
to him. These form the indication that CinC. Second Fleet will be in
command of a large Task Force comprising the Third Fleet, Combined Air
Force, some carrier divisions, and Battleship Division Three. No
movement from home waters has been noted.
Third Fleet.-The Commander Second Base Force originated what appears to
be a movement report. He also sent one to R. N. O. TAIHOKU, information
to CinC. Third Fleet. There were other units tentatively placed in Third
Fleet who sent dispatches in which the Tokyo movement report office was
an addressee. It is expected that the Third Fleet will move from the
Sasebo area in the near future. This Second Base Force was having quite
a bit of traffic with several Air Corps a while ago and may be
transporting air units or equipment.
Fourth Fleet.-Not much activity in this fleet. The amount of traffic
between this fleet and Palao is noticeable with the submarines still
interested in Jaluit.
 Communication Intelligence Summary, 19 November 1941
General.-Traffic volume normal. Traffic from Fourth Fleet and Mandates
was noticeably less than usual. Traffic on the northern circuits also
very light. Some tactical traffic received from Combined Fleet units.
There was been a noticeable increase in the afloat traffic over the
normal amount usually seen. Fleet units seem to have a great deal of
business with other Fleet units both within and outside of their own
organization. Staff Officers are frequently addressed at other than
their normal locations. The activity at Tokyo has subsided somewhat in
that there were fewer general messages than for the past few days. Tokyo
Intelligence sent out several messages addressed to Second Fleet,
Submarine Force and Carrier Divisions. One was sent to SAMA for
information to French Indo China Forces and South China Fleet. The Navy
Minister sent out two AlNavs. The Direction Finder net is still active
with all stations sending in reports and Tokyo plotting station making
reports to major commanders.
Combined Fleet.-The flagship of Battleship Division Three appears today
at Sasebo, its southern jaunt apparently having been completed.
Destroyer Squadron Four and Two appear associated with the Third Fleet.
CinC Second Fleet continues his activity, being still associated with
Combined Air Force, French Indo China Force, Third Fleet, and today with
Carrier Division Three. Carrier Division Three was in Takao and returned
to the Empire a week ago and has been associated with Third Fleet since.
A Bako activity addressed the Chief of Staff Second Fleet, Third Fleet
and Combined Air Force. The Chief of Staff Second Fleet addressed an
urgent dispatch to CinC. French Indo China Fleet information to Third
Fleet and Commander Cruiser Division Five.
Third Fleet.-Active as noted above. Several more units of this fleet and
of the Base Forces originated movement reports but no indication of
direction. CinC. Third Fleet is still in Sasebo.
Fourth Fleet.-Activity in Mandates still centers about the Third Base
Defense Force at Palao. Traffic between this force, Tokyo and the Second
Fleet was considerable. One call (SITI 4) appeals at Jaluit today. This
call has been identified as Carrier Division Four and if the one message
is correct it appears that this Carrier Division (ZUIKAKU) is in the
Jaluit area. This is *not* confirmed as no other indications have been
found and its presence at Jaluit is doubted, attributing the message to
be a communication error.
Fifth Fleet.-Flagship located at Yokosuka. The CinC. Fifth Fleet
appeared in a few dispatches from Tokyo but no other activity seen.
 Communication Intelligence Summary. 20-21 November 1941
General.-Traffic volume for past two days has been higher than normal.
Tokyo originators active with messages addressed to all major
commanders. N. G. S. sent a UNI WIWI to Commandant BAKO for information
to Chief of Staff South China Fleet and Canton. The Personnel Bureau at
Tokyo become very active on the 21st sending out a series of long
personnel messages. The activity at Tokyo identified as R. D. F.
plotting stations increased his recent high volume of messages with a
long four part message addressed to all major commanders. He also
addressed several dispatches to the Direction Finder net, indicating the
employment and results being obtained by this activity. The traffic load
on the Tokyo-Takao circuit was very heavy on the 21st, so heavy that be
circuit was in duplex operation most of the mid-watch.
Combined Fleet.-Flags of both First and Second Fleets are in Kure area
and most of both fleets remain in Kure-Sasebo area. Battleship Division
Three still in Yokosuka area. Traffic to and from the CinC. Second Fleet
continues abnormally high. A list of units addressed by him or who sent
traffic to him and CinC. Third Fleet over the past two days follows:
MIRA 9 (Carrier Division Three) ENO 7 (Unidentified)
TAE 1 (Airron 7) AKU 8 (Air Unit)
KAME 5 (Airron 6) KUSU 7 (Unidentified)
YAWI (Crudiv 5) SATU 88 (Unidentified)
KENU 3 (Crudiv 7) KUNI 88 (Unidentified)
RESE 4 (Desron 3) OYU 9 (Unidentified)
AKI 0 (Desron 4) KONA 0 (Unidentified)
TIYA 7 (Comdr. 1st Base For) NOTU 6 (Unidentified)
SASE 3 (Comdr. 2nd Base For) NETE 5 (Unidentified)
YOMO 9 (Desron 5) NSI 3 (Unidentified)
REA 2 (Shiogama Air Corps) SUTE 1 (Unidentified)
KUNO 9 (Erimo) YAYU 1 (Unidentified)
MIMO 3 (Air Unit ?) MARE 5 (Unidentified)
TUE 7 (Unidentified) Plus 11 Marus.
This list is not the complete estimate of forces being assembled by him
but only the ones occurring in the past two days. Each one appeared not
only with the CinC. Second Fleet but with the Third Fleet and with one
of the units now in South China or Taiwan-South China Address. A
complete list is being made up but was not finished at this writing.
Assuming that the entire Second Fleet will be included in this
organization and that each unit addressed will either participate or
contribute somewhat to the Task Force it appears that it will comprise a
good portion of the navy. One item stands out-so far there has been
practically no submarine units mentioned by the Second or Third Fleets
in connection with South China activities. Commander Submarine Force has
not been included in traffic. He does appear in Tokyo Fourth Fleet and
 Communication Intelligence Summary, 20-21 November 1941
Mandates and Fourth Fleet.-The R. N. O. Palao and Palao radio stations
have remained active with the Fourth Fleet and 5 Yokosuka for days. This
is taken to indicate a coming concentration of forces in Palao which
would include the Fourth Fleet and some of the Second Fleet who has also
been active with the R. N. O. Since the activity of the Second Fleet
Commander has been so great it may be that he will assign some non-
Second Fleet units to that area but just which ones is not yet known.
From information from radio sources there is no indication of any
concentration now at Palao beyond the Third Base Force which is based
there. There has been no traffic for other fleet units routed there and
the Maru traffic to Palao is far less than the normal flow to that area.
With the arrival of Siti 4 (yesterday reported as either a carrier unit
or submarine unit and now identified as a submarine squadron of the
Submarine Fleet) the concentration of naval forces in the Marshalls is
far greater than that existing at Palao.
 Communication Intelligence Summary, 22 November, 1941
General.-Traffic volume somewhat greater than normal. Only one tactical
circuit heard today, indicating that Combined Fleet tactical exercises
are now completed. The Navy Minister originated several AlNavs and sent
two other messages, one to CinC, Fourth Fleet and one to Yokosuka and
Commander Submarine Squadron Five. Tokyo Intelligence sent out the usual
long messages to CinC Combined Fleet, CinC Second Fleet and CinC Third
Fleet. BuMil addressed Fourth Fleet, Truk, Pagan Civil Engineering
Section At Peleliu and Yokosuka Another unidentified Tokyo originator
sent a priority message to all major flags and China Fleet, information
to ANOS at Taihoku and Palao. Sasebo addressed one to Chief of Staff
French Indo China Force, information Chief of Staff Second Fleet, Bako,
Sama, Chief of Staff South China, Chief of Staff Third Fleet, commander
Cruiser Division Seven and Commander Destroyer Squadron Three Cruiser
Division Seven and Destroyer Squadron Three to South China Area soon
While the Direction Finder Net is still active, the station at Palao
sent in more bearings than usual for that station.
Combined Fleet.-CinC. Combined originated only one dispatch to two
unidentified calls, one a Maru, for information to CinC. Third Fleet.
CinC Second Fleet was again prolific with many messages addressed to
Third Fleet and Combined Air Force. The amount of traffic interchanged
between these three commanders was very great. One message addressed
many units as follows:
CinC. Second Fleet. To: NETE 5 (Crudiv?), KOO 2 (Subrons 5) TIYU 66
(CinC. Third Fleet), SUYO 44 (CinC. Comb. Air Force), MIRA 9 (Cardiv
3) RESE 4 (Desron 3), KORE 4 (Second Fleet) (Collective), less
Crudiv 8 and unidentified 2nd Fleet unit), SUTI 2 (BatDiv 3) (at
Kure and Sasebo), Airron 7 (at Kure), SUTI 1 (?) (at Kure), SATU 8
(?) (at Kure), META 0 (AKASHI) (at KURE) META 2 (ASAHI MARU), TUFU 2
(?), NARI 33 CinC. China Fleet), KAKE 66 (CinC. South China Fleet),
MISI 66 (CinC. Comb. Fleet).
Third Fleet.-CinC. Third Fleet received a dispatch from "RIKUGUN
SANBOUTEU MAEDATI SEUZEU (at Tainoku). This is translated as "Army Chief
of Staff General MAEDATI and indicates the linking of the Taiwan Army
Forces with Third Fleet. The CinC. Third Fleet continues his association
with Combined Air Forces.
Fourth Fleet.-CinC Fourth Fleet was mostly occupied with the Sixth Base
Force at Jaluit and AirRon 24 now in Jaluit area. The Third Base Force
at Palao and the RNO Palao are still addressing the CinC Fourth and
Yokosuka. He also received one from Commander Submarine Force.
China.-The Commander French Indo China Force sent one message to CinC.
Combined Fleet for information to CinC. Second Fleet. Bako sent one to
Secretary Fourth Fleet and Secretary Submarine Fleet, Secretary Carrier
Divisions, Secretary Fifth Fleet, Sama and French Indo China Fleet.
 Communication Intelligence Summary, 23 November 1941
General.-Traffic volume normal. High precedence traffic has increased.
Some of the high precedence dispatch headings are listed:
1. MAYURU (Tokyo address) to HORONO MUSEKU (Collective Shore Information
Chiefs of Staff Combined, 1st, 2nd, 3rd, 4th,
5th, and Southern Expeditionary Force.
2. Third Fleet Chief of Staff to Second Fleet Chief of Staff Information
Combined and Southern Expeditionary Force
Chief of Staff.
3. KESANA EONO (Tokyo) to Chiefs of Staff Third Fleet and Southern
Expeditionary Force. Information "SANKUYUTI"
at Sama Hainan.
4. SUIFITE 1 (Unidentified Fleet unit) to Radio Takao, Hainan, Flagship
NWA 2, Information Tadio Tokyo and Second
5. Imakuni [sic] Air to Iwakuni Air Detachment at NAHA Information Kure,
Bako, and MINO 3 in Takao.
Personnel Tokyo also originated several priority dispatches to First
Fleet Third Fleet, and others. The following WE address was followed by
Sasebo Radio in the delivery of a personnel Bureau dispatch
"SAHOTI.RENGO.RI.SI." An unidentified fleet unit (SUTE 1) listed
recently in Kure appeared on radio circuit with Takao Radio. Also on
this circuit were the following:
KENU 3-CruDiv 7 Flagship?
HOWI 2-Fleet unit associated with Second Fleet.
EKE 8-Fleet unit associated with Second Fleet.
MUSE 5-Naval Auxiliary associated with Second Fleet.
The above units received delivery of the long NIKA dispatch originated
by CinC Second Fleet on the 21st of November and which appeared to
outline the forces expected to operate in the Indo-China general area.
Combined Fleet.-CinC Combined was included, as always, in all exchange
of fleet commander traffic, but no important messages originated by him
cepted. First Fleet was very quiet. Second Fleet messages mentioned in
summaries of 22nd were still being circulated but Third Fleet appeared
as the most active unit in today's traffic. Indications are that Third
Fleet units are underway  in a movement coordinated with the
Second Fleet, Combined Air Force and French Indo China Force. Commander
French Indo China Force (So. Exp. For.) was included in all important
traffic from Second, Third and Combined Air Commanders, Hainan
addressees were included in nearly all high precedence messages
concerning these forces and may indicate a rendezvous of forces in that
area. Palao appeared as an information addressee on a portion of the
traffic. Fourth Fleet activity involved Palao area on one end and
Marshalls on the other. With no means of substantiating the impression,
it is believed that more submarines are operating in, or from, the
Marshalls than it has been possible to definitely place from radio
interceptions. It is recalled that there was an exchange between Staff
Communication Officers of the Submarine Force and Fourth Fleet with
Jaluit included as either action or information around November 1st and
that Jaluit opened a direct circuit to Yokosuka early this month,
apparently to relieve traffic congestion from that area. Jaluit Radio
has been heard on various frequencies using and working with units using
tactical or secret type calls, while the main submarine frequency of
6385/12770 has been relatively inactive.
Air.-Combined Air Traffic remains associated with Taiwan area, while the
Mandate Air units continue high level of activity, covering the whole
Mandate area. Carrier Divisions were relatively quiet, but with Carrier
Division Three definitely associated with Second Fleet operations.
China-CinC. China and South China not included with the Second, Third
Air Force and Southern Expeditionary Force traffic and were quiet.
Bearings from Cavite and Guam place CinC. South China east of Taiwan,
but this is believed questionable.
Nothing was seen to contradict impressions gathered during the past few
days and summarized previously, that movement of forces is either
imminent or actually underway, at least in part, to the southward, with
covering forces operating from the Mandates, and possibility of a
striking force assembled or gathering in the Palao area.
 Communication Intelligence Summary, 24 November, 1941
General.-Traffic volume normal. High precedence traffic above normal.
Traffic analysis impresses are unchanged from yesterday's report. The
difficulties of identifications have prevented more definite information
of vessels (and fleets to which attached) that appear to be moving south
from Kure-Sasebo area. If the poor reception prevailing here the last
two days can be disregarded and the assumption made that Radio Heeia
intercepted their "share" of the total traffic, the following
impressions are worth something:
(a) The falling off of traffic to China addresses.
(b) The increased activity among third fleet addresses with a high
percentage of what appeals to be movement reports.
(c) The above normal activity in the Mandates both ashore and afloat
The association of Second Fleet, Third Fleet and Southern Expeditionary
Force continues as usual. Palao and Jaluit appear prominently in
dispatch traffic, the Second Fleet Commander with the former, and the
Submarine Force Commander with the latter.
First and Second Fleets.-Very little activity in First Fleet. The radio
call believed to represent the flagship of Cruiser Division Seven
originated a dispatch to Commander Cruiser Division Seven, CinC. Second
Fleet, Commander Southern Expeditionary Force, and Radio Sama, Takao,
Sasebo, and Tokyo. The CinC. Second Fleet continues to appear as the
Task Force Commander of a large number of units from First and Second
Fleet plus Carrier Division Three and Combined Air Force units.
Third Fleet.-Large number of dispatches involving Third Fleet units,
some of which appear to be movement reports. The fact that CinC Third
Fleet appears as information addressee on many dispatches to and from
Second Fleet units indicates that these two fleets will be closely
associated in any future operations. Yesterday, a large number of
dispatches associating Carrier Division Three with Cinc. Third Fleet.
Fourth Fleet and Mandates.-Fourth Fleet appears to be concentrated in
Truk area since all of the recent definite reports from Fourth Fleet
vessels have come from Truk. Air Squadron Twenty-four and perhaps a
large number of submarines from the Submarine Force are in the Marshall
Submarines.-Comparatively little activity.
Carriers.-No definite indications of location.
Combined Air Force.-Commander Kanoya Air appears in the Takao area.
Otherwise no change.
 Communication Intelligence Summary, 25 November, 1941
General.-Traffic volume normal. Receiving conditions much improved over
last two days. Tokyo personnel bureau active with messages to various
units. Tokyo originated one UNI WIWI to CinC. Combined Fleet, CinC.
Second Fleet CinC. Third Fleet, CinC. Fourth Fleet and CinC. French,
Indo China Force plus Yokosuka, Kure and Maizuru. The Navy Minister
originated several AlNavs. A Direction Finder Net, controlled by Tokyo
radio was active with secret calls being sent by the five stations. The
entire fleet traffic level is still high which leads to the conclusion
that organizational arrangements or other preparations are not yet
Combined Fleet.-Little activity by CinC. First Fleet. CinC. Second Fleet
remains highly active as an originator, addressing Third Fleet, Air
Forces and South China units. A Second Fleet unit and a submarine
division or squadron arrived in Takao communication zone today.
Crudivision Seven which previously arrived there has been associated
with Destroyer Squadron Three which indicates the presence of that unit
in Takao vicinity. Palao and Second Fleet still exchanging messages. Two
new units to be associated with CinC Second Fleet and the Task Force now
forming are the North China Fleet and Defense Division One.
Air.-Through the identification of a call made today Genzan Air Corps
has been in Saigon since the eighteenth. We believe that other units of
the Combined Air Force have moved from Taiwan to the French Indo China
Area although this is not yet verified. One or more of the Carrier
Divisions are present in the Mandates.
Fourth Fleet.-CinC. Fourth Fleet is still holding extensive
communications with the Commander Submarine Fleet, the forces at Jaluit
and Commander Carriers. His other communications are with the Third,
Fourth and Fifth Base Forces.
 Communications Intelligence Summary, 26 November 1941
General.-Traffic volume normal. All circuits heard well except for
Tokyo-Takao circuit which faded early. Traffic picture about the same as
for the past week. Intra-fleet traffic still very heavy and Tokyo
Bureaus still dispatching AlNavs. The Tokyo Intelligence and Direction
Finder plotting units addressed a succession of urgent dispatches to the
major commands and to the CinC. Second and Third Fleets in particular.
The only MAM schedule was NR15 which was first broadcast on the twenty-
fifth. Takao and Bako originated more traffic today than usual, it was
addressed to Third Fleet mostly but the CinC. Second Fleet and the China
Fleets came in for their share. Tokyo radio is working the ISIZU
(flagship South China) SAMA and CAMRANH Bay radio stations directly
Takao is also working ITSUBA (Spratleys).
Combined Fleet.-Cruiser Division Seven today began receiving traffic via
SAMA, indicating the arrival of that unit in HAINAN waters. While no
indications were seen that Destroyer Squadron Three also arrived it is
probable that this unit is still in company with Cruiser Division Seven
and is also present at Hainan. The Takao, former flagship of the Second
Fleet became active in the traffic today being associated with the
Second and Third Fleets. The tanker HAYATOMO appeared in several of
CinC. Second Fleet's dispatches today as well as the SOYO MARU. No
movement is evident yet of any of the flags of the newly formed force.
The traffic between Second, Third, Fourth Fleets and the Combined Air
Force still continues at its high level.
Fourth Fleet.-No change in Truk location. CinC. held extensive
communication with Saipan forces as well as Palao forces. The KATORI and
CinC. Submarine Fleet appear to be at or near Chichijima.
Fifth Fleet.-The CinC. Fifth Fleet was included in some of the
dispatches of the Second Fleet and is associated with the new Task
Submarines.-As noted above Commander Submarine Force is in Chichijima
area. The Submarine Squadron NETE5's location is somewhat uncertain
today due to one dispatch being routed to MAIZURU. The routing of this
dispatch is doubted because of the indication of her arrival at Takao
yesterday and her previous association with Cruiser Division Seven.
China.-Two Marus of the Third Fleet left Bako for Sama today.
Third Fleet.-Active as above but no indication of large scale movement
from the Sasebo area.
 Communication Intelligence Summary, 27 November 1941
General.-Traffic volume a little below normal due to poor signals on the
frequencies above 7000 kcs. Tokyo-Takao circuit unreadable on mid-watch.
Some tactical traffic intercepted from carriers. Bako, Sama, and Saigon
active as originators, addressing traffic to each other and to the
Chiefs of Staff of Second, Third Fleets and Combined Air Force. Bako
addressed the Chief of Staff Third Fleet information Destroyer Squadrons
Four and Five and Chief of Staff Second Fleet. The main Tokyo originator
today was the Intelligence activity who sent five dispatches to the
major commanders. The Direction Finder activity was very high with all
stations sending in bearings including the Marshall Islands Stations
which has been silent for the past four days.
COMBINED FLEET.-No further information as to whether or not Destroyer
Squadron Three is in Hainan area but is believed to be still with
Cruiser Division Seven in that area. There is still no evidence of any
further movement from the Kure-Sasebo area. The Chief of Staff Combined
Fleet originated several messages of general address. He has been fairly
inactive as an originator lately. CinC. Second Fleet originated many
messages to Third Fleet, Combined Air Force and Bako.
THIRD FLEET.-Still holding extensive communication with Baka, Sama South
China Fleet and French Indo China Force. The use of WE addresses is
increasing, those occurring today were:
"DAIHATIFUTABUTAISANBOTEU" (in Taihoku)
"KIZUKEYAMASITABUTAI" (in care of RYUJO)
There is nothing to indicate any movement of the Third Fleet as yet.
FOURTH FLEET.-CinC. Fourth Fleet frequently addressed dispatches to the
defense forces in the Mandates. Jaluit addressed messages to the
Commander Submarine Force and several submarine units. The Saipan Air
Corps held communication with Jaluit and CinC. Fourth Fleet. The Civil
Engineering Units at IMIEJI and ENIWETOK were heard from after being
silent for weeks. Chitose Air Corps is in Saipan and Air Squadron
Twenty-four is still operating in the Marshalls. No further information
on the presence of Carrier Division Five in the Mandates.
AIR.-An air unit in the Takao area addressed a dispatch to the KORYU and
SHOKAKU. Carriers are still located in home waters. No information of
further movement of any Combined Air Force units to Hainan.
SUBMARINES.-Commander Submarine Force still in Chichijima Area.
 Communication Intelligence Summary, November 28, 1941
General.-Traffic volume normal. Communications to and from South China
and between Mandates and Empire very heavy. No tactical traffic seen. As
has been previous]y reported the suspected Radio Intelligence net is
very active and is becoming more so. The TOKYO plotting activity
addressed more messages to the Radio net than previously and most of
these sent for information to the Major Commanders. Much traffic also
was directed to NRE0 (the TOKYO D. F. Command) from all eight stations
in the Mandates and OMINATO. This Command also originated messages of
high precedence to the Major Fleet Commanders. This activity is
interpreted to indicate that the R. I. net is operating at full strength
upon U. S. Naval Communications and IS GETTING RESULTS. TOKYO
originators were active with messages of high precedence to the
Commander in Chiefs of the Second and Third Fleets and Combined Air
Force. The Navy Minister sent to Alnavs. The Chief of the Naval General
Staff sent one to the Chief of Staffs of Combined Air Force, Combined
Fleet, Fourth Fleet, Third Fleet, French Indo-China Force, Second Fleet
and RNO PALAO. The BUAERO sent one to Chief of Staff Fourth Fleet info
IMIESI and 11th Air Corps at SAIPAN.
Combined Fleet.-No indication of movement of any Combined Fleet units.
Commander in Chief Second Fleet originated his usual number of
dispatches to Third Fleet and Combined Air Force. The units paid
particular attention to by the Commander in Chief Second Fleet were
CARDIVS Five and Seven and
DESRONS Two and Four and SUBRON Five. No traffic today from the TAKAO
Third Fleet.-Little activity from Third Fleet units save for the
Commander in Chief. The impression is growing that the First Base Force
is not present with the bulk of the Third Fleet in SASEBO but it is not
yet located elsewhere. The Army Commander in TAIHOKU is still holding
communications with the commander in Chief Third Fleet. Two Third Fleet
units arrived at BAKO and are apparently returning to KURE from BAKO.
Fourth Fleet.-Bulk of Fourth Fleet still at TRUK. The Commander in Chief
Fourth addressed message to the Sixth Base Force at JALUIT and the
Fourth Base Force at TRUK. Yokohama Air Corps is at RUOTTO and WOTJE and
held communications with AIRRON Twenty-Four and KAMOI.
Sixth China.-SAMA sent several messages to shore addresses in the
Empire. SAMA also addressed the OMURA AIR CORPS in several messages
which went for information to SAIGON and TOKYO. TAKAO radio station
addressed the Chiefs of Staff Combined Fleet, Second Fleet, the French
Indo China Force and Combined Air Force. TAKAO Air Corps addressed
SUKUGAWA Air Corps and YOKOSUKA Air Corps. A representative of a HAINAN
office now at SAIGON originated several messages to the Naval Bases at
SASEBO and KURE. The Commander in Chief China Fleet originated more
traffic than usual and addressed his fleet collectively for information
to the Commander in Chief Second and Commander in Chief Third Fleets.
Submarines.-Except for the mention of SUBRONS Five and Six in two
dispatches there was no submarine activity today.
 Communication Intelligence Summary, 29 November 1941
General.-Traffic volume above normal, The traffic to South China still
very high. Automatic transmissions was attempted on the Tokyo-Takao
circuit but was a failure and traffic sent by hand. A good share of
today's traffic is made up of messages of an intelligence nature. Tokyo
Intelligence sent eleven messages during the day to Major Commanders
both ashore and afloat, while the radio intelligence activity at Tokyo
sent four long messages to the Major Commanders. In addition to the
stations normally reporting to Tokyo, radio Yokosuka sent in reports.
This station had not previously been seen to submit reports. The
Direction Finder Net controlled directly by Tokyo was up during the
night with much activity. One message for Jaluit Radio Direction Finder
Station included Commander Submarines for information. The Navy Minister
originated his usual two AlNavs and the Naval General Staff addressed
Commanders Second Fleet Third Fleet, Combined Ail Force and the South
China Units. The unit which has been addressed as the "103rd Air Group"
originated one dispatch today whose address was composed entirely of
enciphered calls. It is apparent that he has no Navy call list. One
address was "JUITIKOUKUUKANTAI" "11th AIR *FLEET*". Since this has
appeared before it is evident that the use of KANTAI is intentional
making the existence of an air fleet positive. Its composition is
Combined Fleet:-The arrival of Air Squadron Seven in Takao area is
confirmed. The presence of Cruiser Division Four in that area is not
confirmed nor denied. The dispatches today indicate that the following
units are under the immediate command of CinC. Second Fleet:
CARDIV THREE DESRON TWO
SUBRON FIVE DESRON FOUR
SUBRON SIX THIRD FLEET
CRUDIV FIVE FRENCH INDO CHINA FORCE
Associated with Third Fleet are two Battleships but their assignment is
not yet definite. Aside from messages which were addressed to Third
Fleet, China and South China Fleets, Combined Air Force and the Naval
General Staff, Commander in Chief Second Fleet was mainly occupied with
the units listed above. Only one message from Commander in Chief
Combined Fleet was seen. This was addressed to YOKOSUKA, Combined Air
Force, CRUDIV Four and BUMILAFF. The HIYEI sent one message to Chief of
Staff Third Fleet.
Third Fleet.-Commander in Chief Third Fleet sent one message to
Comdesron Five, Number Two Base Force, Number One Base Force, Defense
Division One and Comdesron Two and Four. He held extensive
communications with the Commander in Chief Second Fleet and BAKO. Two
more units of Third Fleet made movement reports.
Fourth Fleet.--Relatively inactive today. Sent one message to Commander
in Chief Second Fleet, Commander in Chief Third Fleet and Combined Air
Force. He is still in TRUK area.
Submarines.-Traffic for Commander Submarine Force was routed through
SAIPAN today. He was at CHICHIJIMA yesterday.
South China.-CRUDIV Seven now in SAMA made a movement report but
direction was not indicated. The French Indo China Force Commander
addressed several messages to Second and Third Fleets as well as TOKYO.
The Commander in Chief China Fleet was active in addressing the South
China Naval Bases and the South China Fleets, all for information to
Commander in Chief Second Fleet.
 Communication Intelligence Summary, November 30, 1941
General.-Traffic volume less than for past few days. Today's traffic
consisted largely of dispatches bearing old dates, some as far back as
26 November. No reason can be given for the retransmission of these
messages unless the high volume of traffic for past few days has
prevented the repetition of dispatches. The number of dispatches
originated on the 30th is very small. The only tactical circuit heard
today was one with AKAGI and several MARUs. The TOKYO Intelligence
activity originated two WIWI dispatches to Major Fleet Commanders. One
urgent dispatch was sent by NGS to Chiefs of Staff Combined, Second,
Third, Fourth, and Fifth Fleets, Combined Air Force; Submarine Force and
Combined Fleet.-The Chiefs of Staff of the Combined Fleet and First
Fleet are in KURE. In the same message the Chief of Staff Second Fleet
was nor at any location. Other traffic indications are that he is at
sea. Commander in Chief Second Fleet sent one to his usual addressees of
the Third Fleet and Combined Air Force but also included KONGO and
HIYEI, which places them as members of his Task Force. The Commander in
Chief Second Fleet is no longer adding PALAO activities and has not for
past two days. The RNO PALAO today addressed two messages to TAIWAN
GUNSIREIBU (TAIWAN Army Headquarters).
Third Fleet.-Commander in Chief Third Fleet addressed two messages to
COMDESRON Two, Four and Five; COMCRUDIV Five; First and Second Base
Forces and Defense Division One for information to Commander in Chief
Second Fleet. No information obtained as to the location of the
Commander in Chief Third Fleet, which gives the strong impression that
he is underway.
Fourth Fleet.-Believed to be still in TRUK area. D. F. activity in
Marshalls a little greater today than normal. JALUIT addressed Commander
Submarine Force and AIRRON 24 in one dispatch. The continued association
of JALUIT and Commander Submarine Force plus his known progress from the
Empire to CHICHIJIMA to SAIPAN makes his destination obviously the
Marshalls. Since one of his large units (SITI4) arrived in the Marshalls
some time ago this unit cannot agree with Com 16 that there is not a
submarine concentration in that area. Every evidence points to a
concentration of not only the small Fourth Fleet submarines there but
also a good portion of the Fleet submarines of the Submarine Force.
AIRRON 24 plus YOKOHAMA AIR CORPS presence in that area points to
intended air-submarine operations from the Marshalls. Also the presence
of a unit of plane guard destroyers indicates the presence of at least
one carrier in the Mandates although this has not been confirmed.
South China.-BAKO active with dispatches to Second and Third Fleets.
Combined Air Force and SAMA. Commander in Chief China Fleet becoming
more and more active as an originator with dispatches to the Task Force.
He made a movement report with the South China Fleet as an information
addressee. The Staff Communication Officer of the South China Fleet was
addressed at Shanghai today.
 Communication Intelligence Summary, 1 December 1941
General.-All service radio calls of forces afloat changed promptly at
0000, 1 December. Previously, service calls changed after a period of
six months or more. Calls were last changed on 1 November, 1941. The
fact that service calls lasted only one month indicate an additional
progressive step in preparing for active operations on a large scale.
For a period of two to three days prior to the change of calls, the bulk
of the radio traffic consisted of dispatches from one to four or five
days old. It appears that the Japanese Navy is adopting more and more
security provisions. A study of traffic prior to 0000, 1 December
indicates that an effort was made to deliver all dispatches using old
calls so that promptly with the change of calls, there would be a
minimum of undelivered dispatches and consequent confusion and
compromises. Either that or the large number of old messages may have
been used to pad the total volume and make it appear as if nothing
unusual was pending.
First Fleet.-Nothing to indicate that this fleet as a fleet is operating
outside of Empire waters. It is believed that such a large percentage of
the First Fleet is operating with the Second Fleet Task Force that this
fleet has ceased to operate in a prominent role.
Second Fleet.-This fleet is believed proceeding from the Kure-Sasebo
area in the direction of South China and Indo-China. Takao does not
appear to play an important role in today's traffic; consequently, the
assumption is made that his fleet is passing up Takao. Certain units of
the Second Fleet Task Force are definitely in the Indo-China area
(Cruiser Division Seven and Destroyer Squadron Three most prominent).
Third Fleet.-Nothing to report except that the same association of
Second, Third Fleets, and Combined Air Force with South China and Indo-
China Forces continues.
Fourth Fleet.-No change in the Fourth Fleet or Mandates area.
Fifth Fleet.-Nothing to report.
Submarines.-Large number of the Submarine Force believed to be in the
area to the eastward of Yokosuka-Chichijima and Saipan Flagship
somewhere in this general area.
Combined Air Force.-No change.
 Communication Intelligence Summary, 2 December 1941
General.-The most prominent factor in today's traffic is the apparent
confusion in the routing of traffic for certain major parts of the
Japanese Fleet. There were instances where the same dispatch was
repeated several times after it appeared on the Tokyo broadcast and also
where Takao Radio received the same dispatch that it had previously
sent. ComSixteen reported Second and Third Fleets in Takao area and that
Takao Radio was broadcasting traffic to these fleets. This broadcast was
not uncovered here and contrary to location reports, there was one
indication that these two fleets were not close to Takao. In several
instances Takao Radio forwarded traffic to Tokyo for these fleets.
Summing up all reports and indications, it is believed that the large
fleet made up of Second, Third and First Fleet units has left Empire
waters but is either not close enough to Takao for good communication or
is proceeding on a course not close to Takao. The change of calls on
December first has prevented this office from making definite statements
at this date of the units now in the Southern area. To further
complicate the situation, Shanghai Radio handled a considerable mount of
traffic which obviously was originated by and destined for units in the
Takao area. The Chief of Staff, South China area continues to appear in
Shanghai ComSixteen reported nine submarines proceeding south by Camranh
Bay. This group is believed to comprise both Submarine Squadrons five
and six, which units normally operate with the First Fleet but have been
included repeatedly in the Second Fleet Task Force for Southern
There was a very high percentage of high precedence traffic originated
both by major forces afloat and Tokyo. Hainan continues as a prominent
address. Palao and Third Base Force is holding the same relative
First Fleet.-Despite the lack of positive identification, the First
Fleet appears relatively quiet. From inconclusive evidence, it appears
as if there may have been a split in the original or normal Combined
Fleet Staff and that these may be two supreme commanders with staffs. As
an example, traffic routing indicates one Combined Fleet call associated
with the Second and Third Fleets and apparently in company while another
Combined Fleet call appears not associated with the Second and Third
Second Fleet.-No units have stood out prominently the last two or three
days. This is partly due to lack of new identifications but contributes
somewhat to the belief that a large part of the Second Fleet is underway
in company. Cruiser Division Seven and Destroyer Squadron Three are
unlocated and unobserved since change of calls.
 Third Fleet.-Nothing to report. Shanghai appeared in an indirect
way in some of the Third Fleet traffic.
Mandates.-Association of Submarine Force and Fourth Fleet continues.
Some traffic for Fourth Fleet units still going through Truk.
Carriers.-Almost a complete blank of information on the Carriers today
Lack of identifications has somewhat promoted this lack of information-
however, since over two hundred 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
Combined Air Force.-This force continues to be associated closely with
Second, Third and Indo-China Fleets. Some units of the Combined Air
Force have undoubtedly left the Takao area.
 Communication Intelligence Summary, 3 December 1941
General.-Traffic volume normal with receiving conditions good. Present
state of call recovery does not permit much detailed information to be
obtained. The extensive use of alternate calls by the major commands
slows up identification of even these Units. Very few units have been
positively identified so far. The Chief of the Naval General Staff
originated three long dispatches to the CINC COMBINED, SECOND and THIRD
FLEETS. The Tokyo Intelligence originated nine dispatches to the same
The presence of the CINC SECOND FLEET in Taiwan waters is not revealed
by radio traffic. In some traffic from Takao the CINC SECOND FLEET is
indicated as having previously received the messages while in others to
Tokyo he is indicated for delivery by that station. It is the impression
that both SECOND and THIRD FLEETS are underway but are not verified by
Radio Intelligence means.
There are some FOURTH FLEET Units in the Marshall Islands area including
some of the FOURTH FLEET Staff. The identity of these units is not
known. The SIXTH BASE FORCE at Jaluit addressed several messages to CINC
Some Swatow Units were addressed at Saigon today indicating a movement
of some South China Units to Saigon. Bako originated many dispatches to
the RNO Taihoku and the Task Force Commander.
No information on submarines or Carriers.
 Communication Intelligence Summary, 4 December 1941
General.-Traffic volume normal with fair receiving conditions. Takao
Radio today instituted a fleet broadcast system using the prefix UTU in
heading so that there are now two fleet broadcasts in operation. So far
only a few messages have been placed on the Takao broadcast. There were
a large number of urgent messages, today, most of these from Tokyo to
the major commanders. Among others Tokyo Intelligence originated a seven
part message to Chiefs of Staff China Fleet, Combined Fleet, Third
Fleet, South China Fleet, French Indo-China Force and Sama. In all, this
activity sent twelve messages to the major commanders.
Combined Fleet.-The outstanding item of today's traffic is the lack of
messages from the CinC. Second Fleet and CinC. Third Fleet. These
previously very talkative commanders are now very quiet. While the Fleet
calls are not yet well identified, the lack of traffic from these
commands cannot be ascribed to that. These two commands are still
prominent as addressees. It is now believed that the CinC. Second Fleet
is in the vicinity of Takao and that the apparently conflicting evidence
is due to traffic destined for the Tokyo UTU broadcast which CinC.
Second Fleet is still copying. The CinC. Combined Fleet sent one message
to an unidentified unit for information to Third Base Force Palao, CinC.
Second Fleet and CinC. Third Fleet.
Fourth Fleet.-The CinC. Fourth Fleet sent a message to Chief of Staff
Combined Air Force, information to Eleventh Air Corps, Chitose Air, Air
Squadron Twenty-four, Third Base Force at Palao and Fourth Base Force at
Truk. No further check could be made today on the presence of Fourth
Fleet units in the Marshalls. Jaluit appeared many times in today's
traffic being associated with Commander Submarine Force, Tokyo Radio and
MUSI 88 (which is believed to be an oil tanker).
South China.-Bako continues as an active originator addressing many
messages to Sama and Saigon. Except for traffic between South China
Commanders, all units in that area quiet.
 Communication Intelligence Summary, December 5, 1941
General.-Traffic volume heavy. All circuits overloaded with Tokyo
broadcast going over full 24 hours. Tokyo-Mandates circuit in duplex
operation. There were several new intercept schedules heard. OMINATO
radio working SAMA and BAKO sending fleet traffic. The Takao broadcast
handling traffic Second and Third Fleet while the Tokyo broadcast is
still handling traffic for these units also. It is noted that some
traffic being broadcast is several days old which indicates the
uncertainty of delivery existing in the radio organization.
There were many messages of high precedence which appears to be caused
by the jammed condition of all circuits.
A plain language message was sent by the Captain, OKAWA from Tokyo to
Takao probably for further relay addressed to FUJIHARA, Chief of the
Political Affairs Bureau saying that "in reference to the Far Eastern
Crisis, what you said is considered important at this end but proceed
with what you are doing, specific orders will be issued soon."
Combined Fleet.-Neither the Second or Third Fleet Commanders have
originated any traffic today. They are still frequently addressed but
are receiving their traffic over broadcast. They are undoubtedly in
Takao area or farther south since the Takao broadcast handles nearly all
their traffic. No traffic from the Commander Carriers or Submarine Force
has been seen either.
Third Fleet.-In one WE address a "Chief of Staff" sent a message to
"Commander Fourteenth Army abroad RYUJOMARU in Third Fleet.
HITOYO.GUN.SATI (IRO 1 REUZEU MARU). A number of MARUS have been
addressing the CINC. Third Fleet.
Fourth Fleet.-The Secretary, Fourth Fleet and Staff Communication
Officer the Fourth Fleet were addressed at Jaluit today strengthening
the impression at the CinC. Fourth Fleet is in the Marshalls. The
Commander of the South China Fleet has been addressing Palao radio and
the RNO TAIHOKU and the Commander Second Fleet.
South China.-SAMA addressed much traffic to CinC. Second Fleet. BAKO
continues as an active originator with many dispatches to Second and
Third Fleet. The Commander Combined Air Force appears to be busy with
the movement of Air Corps. SHIOGAMA Air and at least two unidentified
corps are moving, probably to Indo-China.
 Communication Intelligence Summary, December 6, 1941
General.-Traffic volume very heavy with a great deal of old traffic
being transmitted. Messages as far back as 1 December were seen in the
traffic. This not believed an attempt to maintain a high traffic level
but is the result of confusion in traffic routing with uncertainty of
delivery. The stations now holding broadcasts are TOKYO (with 3 distinct
and separate broadcasts), SAIPAN, OMINATO and TAKAO.
Yesterday's high level of traffic from TOKYO originators was maintained
with the Intelligence activity still sending periodic messages.
Practically all of TOKYO's messages carry prefixes of high priority.
Combined Fleet.-Still no traffic from the Second and Third Fleet
Commanders. These units are sending their traffic via the TAKAO and
TOKYO broadcasts. The Commander in Chief Combined Fleet originated
several messages to the Carriers, Fourth Fleet and the Major Commanders.
Fourth Fleet.-The Commander in Chief Fourth Fleet is again in the TRUK
area. It is doubtful that he ever went to JALUIT although it is certain
that some members of his staff were there over the past few days. There
is a definite close association between the Third Base Force at PALAO
and the forces in South China. This unit is constantly sending messages
to the Chief of Staff the Second Fleet, Third Fleet, Indo-China Forces
and BAKO. It is being almost entirely neglected by Commander in Chief
Fourth Fleet under whose command it normally operates. RONGELAB radio
addressed the PALAO weather observer.
Fifth Fleet.-This fleet appears dispersed about the JAPAN Sea with
OMINATO broadcasting traffic for this unit.
Submarines.-The Commander Submarine Force originated two messages to his
command. These are the first two originated since 1 December. He is
definitely in the MARSHALLS.
South China.-Nothing new to report. BAKO, SAMA and TAKAO still sending
many messages to the Task Force.
Page maintained by Larry W. Jewell, firstname.lastname@example.org. Created: 12/13/96 Updated: 12/13/96