History Friday: Technological Surprise & the Defeat of the 193rd Tank Battalion at Kakuzu Ridge

In April 1945 the US Army’s 27th Infantry Division launched an attack against the Kakuzu Ridge position held by the Imperial Japanese Army on Okinawa with the 193rd Tank Battalions 30 thirty tanks, self-propelled assault guns, and attached armored flame throwers from the 713th Flame Tank Battalion. When the battle was over, 22 of the 30 armored fighting had been destroyed in a coordinated ambush by Japanese anti-tank guns, artillery, mortars and suicide close assault teams. Among the dead was the battalion commander of the 193rd, on whom blame was laid for attacking without American infantry in close support. This battle is referenced in almost every narrative account of Okinawa as proof of the tougher defenses American soldiers and marines would face in an invasion of Japan.

It turns out that while this particular narrative has a great deal of truth, it isn’t the whole truth and hides the most important one. In a photo film negative image of British Prime Minister Winston Churchill’s comment that “In war, The Truth must have a bodyguard of lies,” This narrative has a huge lie buried in a bodyguard of truth.

The most important truth of this battle was that American troops suffered a technological surprise. The Japanese were listening to the SCR-300, SCR-500 and SCR-600 series frequency modulated (FM) radios of American infantry, tanks and artillery forward observers at Kakuzu Ridge (and other battles through out the Pacific in 1945) with Japanese Type 94 (1934) Mark 6 walkie-talkie radio that was issued to every Japanese infantry battalion.

MacArthur’s forces in Luzon and Mindanao discovered this fact when artillery forward observers in Luzon started hearing Japanese Army radio traffic and attempts to spoof artillery calls for fire that failed with mutual cursing in broken English between American and Japanese units. In addition the 41st Infantry Division over ran Japanese command centers on Mindanao that included this Japanese radio. In fact, MacArthur’s technical intelligence teams published a quite useful article in the August 1945 issue of the War Department’s Military Intelligence Division INTELLIGENCE BULLETIN on how to convert the Japanese Type 94 Mark 6 walkie-talkie to American batteries and vacuum tubes to supplement American radios if captured!

This brings up several questions as to how that technological surprise affected the final battles of the Pacific War, the proposed invasion of Japan and why US Army historians failed to mention this in their histories.

This is what the US Army Green book history “OKINAWA: THE LAST BATTLE,” by Roy E. Appleman, James M. Burns, Russell A. Gugeler, and John Stevens said about this battle:

Chapter VIII:
.
The Attack of 19 April on the Shuri Defenses
.
At 0830, just before the infantry left the protection of the little fold in front of Kakazu, tanks in groups of three and four in column formation began moving across Kakazu Gorge; they then continued southward through the saddle between Kakazu and Nishibaru Ridges. Altogether about thirty tanks, self-propelled assault guns, and armored flame throwers moved out of the assembly area that morning for a power drive, against the Japanese positions, Company A of the 193d Tank Battalion making up the major part of the force. Three tanks were lost to mines and road hazards in crossing the gorge and the saddle. As the tanks moved down the road in column, a 47-mm. antitank gun, firing from a covered position to the left on the edge of Nishibaru Ridge, destroyed four tanks with sixteen shots, without receiving a single shot in return. The tank column hurried on south to look for a faint track leading into Kakazu that had shown on aerial photographs: the column missed it, lost another tank to antitank fire, and then in error took a second little-used trail farther south and began working over enemy positions encountered in the face of the escarpment and in the relatively flat country to the east of Kakazu. Discovering that they could not reach the village from this point, the tanks retraced their way to the main road, turned back, found the right trail, and were in Kakazu shortly after 1000. They moved around and through the village, spreading fire and destruction; Kakazu was completely shot up and burned during the next three hours. Fourteen American tanks were destroyed in and around the village, many by mines and 47-mm. antitank guns, others by suicide close-attack units, and more by artillery and mortar fire. During the day six tanks in the Kakazu-Nishibaru area were destroyed by suicide attackers using 22-lb. satchel charges, which were usually thrown against the bottom plate. A majority of the tank crew members were still living after the tanks had been disabled, but many were killed by enemy squads that forced the turret lids open and threw in grenades.21
[203]
.
At 1330, since it was now evident that infantry would not be able to reach them, the tanks received orders to return to their lines. Of the thirty tanks that had maneuvered around the left end of Kakazu Ridge in the morning, only eight returned in the afternoon. The loss of twenty-two tanks on 19 April in the Kakazu area was the greatest suffered by American armor on Okinawa in a single engagement.22 The tanks had operated wholly without infantry support. Four of the twenty-two were armored flame throwers, and this was their first day in action. Some crew members of tanks destroyed by antitank gun fire dug pits under their tanks and remained hidden forty hours before they escaped, incredibly unmolested by the scores of Japanese within 100 yards.
.
The Japanese had guessed that a tank-infantry attack would try to penetrate their lines between Nishibaru Ridge and Kakazu Ridge, and they had prepared carefully for it. Their plan was based on separating the infantry from the tanks. The 272d Independent Infantry Battalion alone devised a fire net of four machine guns, two antiaircraft guns, three regimental guns, and the 8i-mm. mortars of the 2d Mortar Battalion to cover the saddle between the two ridges. The machine guns were sited at close range. In addition, two special squads of ten men each were sent forward to the saddle for close combat against the infantry. One group was almost entirely wiped out; the other had one noncommissioned officer wounded and three privates killed. The enemy defense also utilized the 47-mm. antitank guns of the 22d Independent Antitank Gun Battalion and close-quarters suicide assault squads. So thorough were these preparations that the Japanese boasted “Not an infantryman got through.” (See Map No. XX.)
.
It was here in the Kakazu-Urasoe-Mura Escarpment area that the most extensive reorganization of Japanese units had taken place just before the American attack. The remnants of badly shattered battalions were combined into a composite unit of about 1,400 men that consisted largely of members of the 272d Independent Infantry Battalion but also included elements of the 13th, 15th, and 23d Battalions. The 21st Independent Infantry Battalion stood ready to support the 272d. The 2d Light Machine Gun Battalion added its fire power.23
[204]

The 2005 PBS Show “Victory in the Pacific” includes the following interview of an Okinawan Student Conscript carrying suicide bombs to Kakazu Ridge the night before the failed 193rd Tank Battalion/105th Infantry Regiment/27th ID attack.

Katsuo Nagata, Okinawan Student Conscript: We student conscripts were ordered to deliver bombs to Kakazu for destroying U.S. tanks. We carried 10 kg bombs on our shoulders and headed for Kakazu at night. The Americans launched a star shell and then came the gunfire. We had to hide in the shade whenever a star shell was up, but finally we managed to deliver the bombs to Kakazu. I heard that, the next morning when the tanks came, they armed the bombs and made suicide attacks into the tanks.

US Army counter-intelligence made a point of interviewing every captured Japanese to screen soldiers from civilians on Okinawa. Katsuo Nagata’s story would have been available to 1948 Army historians.

Next, there is a post-Okinawa wartime Military Intelligence report titled “Information on Japanese Defensive Installations and Tactics” that has translations of IJA 32d Army directives captured in Ushijima’s final headquarters, where his iron discipline on destroying valuable documents collapsed in a round of senior officer suicides. In it there is 32d Army Directive #13 which states:

32D ARMY COMBAT DIRECTIVE No. 13
1. The capacity of the enemy’s. M1 tank to cover terrain must not be
disregarded.
.
We must not neglect the organization of antitank positions in areas
believed to have difficult terrain.
For example, between 3 April and 4 April, 5 enemy tanks advanced
against the 62d Division’s KADANI Det’s UGUSUKU (TA: 8781 W) positions.
.
2. It is increasingly,clear that the enemy’s combat strength is in tanks
and that fighting against the American land army is practically the same things
as fighting against the M1 and M4 tanks.
.
It is necessary that the construction and organization of positions
be made in accordance with all the above considerations.

You see this particular quote in many documents and histories on Okinawa, often with the “M-1” being changed to “M-3” for the Stuart light tank. This is a mistake. as you will see in the following passage from the same directive:

COUNTERPLANS
.
1. Organize close-in attacks beyond the range (135 meters) of the enemy’s
flame thrower attacks.
.
2. Prepare several entrances in such a way that they will give mutual
support.
.
3. It will be most impossible to bring about complete destruction /of
the enemy/doing nothing at all or with all the personnel flinching inside
the caves.
.
4. Maximum effectiveness is attained with the 47mm AT gun by using.delayed
fire against the M-4 type tank at very close range.
.
Example:
At about 1200 4 April, 5 M-4 tanks (one of them was an M-1) attacked
hill 85 southeast of Oyama (TA: 8179 VW, With 20, rounds of 47mm AT gunfire
they were stopped and set afire, and extensive bat tie. damage resulted*
.
Successful results are achieved by remaining concealed and through the
use of slashing concealed fire at very close range.

From the context above you can see that 32d Army has tagged M4 Sherman flame thrower tanks as “M-1”. The question is “Why?”

The answer my research has uncovered is that the US Military did not have a set naming convention for Hawaii built flame tanks during World War II. It depended upon who you talked to and which battle. The US Army Chemical Warfare Service Iwo Jima & Okinawa documents called them “flame thrower, mechanized, POA-CWS, H1-H2.” American Tenth Army and lower level unit official documents shortened it to variants of “POA-CWS-H1.”

US Marine & US Army observer documents on Iwo Jima referred to flame tanks as “CB-Mk-1” for “Construction Battalion Mark – 1” since the US Navy SeeBees were heavily involved in the production and operation of the first eight prototype flame tanks on Iwo Jima. In combat on Iwo Jima, radio calls for flame tanks were almost certainly shortened to either “Send up a Mark One” or “Bring up a Em One.”

The date of Directive No. 13 was before USMC divisions on Okinawa assaulted the Shuri Line with flame tank support from the 713th flame Tank Battalion. For 32d Army to me using the “M-1” naming convention means they got it from the Japanese garrison on Iwo Jima.

Given the totality of the August 1945 War Department INTELLIGENCE BULLETIN, the “Information on Japanese Defensive Installations and Tactics” report, the fact that a 1946 FIELD ARTILLERY JOURNAL mentioned the Type 94 Mark 6 in an article on Luzon fighting, and the 1948 publication date of “OKINAWA: THE LAST BATTLE,” by Roy E. Appleman, James M. Burns Russell A. Gugeler, and John Stevens. The only conclusion I can come to is that Army historians were as truthful as they were allowed to be. That has a lot of implications for historical scholarship for the last 8-to-12 months of World war II in the Pacific.

NARRATIVE DESTRUCTION & LESSONS LEARNED
In closing this column I observe two fearful symmetries.

The first fearful symmetry was that the Imperial Japanese ended their war with America at Okinawa as they began it at Pearl Harbor. There was a technological surprise with a tactical doctrine aimed at what they perceived as Democratic America’s strategic weakness. Its unwillingness to take casualties. At Pearl Harbor, the Japanese had the A6M Zero with their massed carrier strike doctrine to sink US Navy battleships and at Kakuzu Ridge they had their monitoring of American FM radio communications combined with suicide bombers to destroy US Army tanks. In both cases America got over its surprise and trumped them both with a strategic technological surprise of its own…the Atomic bomb.

It did not matter how willing the Japanese military were to die in defense of the Japanese homeland if America could simply nuke them from 30,000 feet.

The second fearful symmetry was discovering that the military and political elites of Truman Administration were no different from our current elites in using wartime classification and post-war lies of omission to hide their mistakes from history. It is quite clear that American knowledge of Imperial Japanese monitoring of our FM communications would have played a huge role in the cancelled invasion of Kyushu, but our elites did not want to admit anything about it.

How many other things were they unwilling to talk about and buried?

In my mind, the first question that needs to be answered is how this happened. My opinion is that, at a minimum, the budget wars arising from the consolidation of the Departments of War and Navy into the Department of Defense played a huge role in this Stalin style rewrite of history. These budget wars were as destructive to readiness as they were to the truth. Since the first Secretary of Defense was fired by Pres. Truman for the catastrophic opening days of the Korean War and was replaced by Secretary of State and former General Marshall to “restore confidence.” More primary source research on this era is clearly called for.

Next, no historical research on the last 12 months of ground warfare in the Pacific War that uses official American military histories can be relied upon. Extensive primary research on both any surviving Japanese and American military documents must be done with the idea that low level American FM radio communications could and were monitored. Only then can you select items from the official histories for use. “Trust, but verify” applies as much to military history as it does to nuclear arms control treaties.

Last, there are two lessons for American military and political elites here.

1) Technological surprise can happen at any time. The Chinese use of internet to penetrate American military (Think US Army’s digital “blue force tracker” to nuclear firing orders) and civilian infrastructure communications plus the growing availability of operational research data analysis software to non-state actors needs to be taken much more seriously.

2) The biggest technological surprise of this research is that both 20th and 21st Century elites can no longer hide their mistakes.

Be it Benghazi or the 193rd Tank Battalion at Kakuzu Ridge on Okinawa, or any other “elite narrative” in our lives, the “Smart Phone era” data analysis tool set can spot lies of omission whenever someone has the inclination to fill in the blanks. Which may be the biggest technological surprise of all.

Sources and notes:
1) Intelligence bulletin. Vol III, No 12, August 1945 issue, Accessed from US Army Combined Arms Research Library, Digital Library

http://cgsc.contentdm.oclc.org/cdm/compoundobject/collection/p4013coll8/id/2070/rec/97

JAP WALKIE-TALKIE

Tests conducted with four Japanese Type 94 (1934) Mark
6 radios on Luzon reveal that it is possible for this amplitude modulated
set to communicate with both the U. S. SCR-610
and SCR-608 FM sets. A small two-unit set of the Walkie-
Talkie design, the Type 94 Mark 6 is standard equipment
within the Japanese infantry battalion.
.
Results, of the texts show that the enemy sets operate satisfactorily
with the SCR-610 within a range of 1/4 to 1 & 1/2 miles,
and with the SCR-608 within a range of 1/2 to 4 & 1/2 miles. Operation
outside these ranges is not recommended. The tests were
conducted by the Signal Technical Intelligence Team, I Corps,
in conjunction with signal personnel from the 25th Division.
The SCR-610 was set up in a truck, with a battery pack and
.
page 25
.
an AN-29 antenna. The signal transmitted by each set was
tuned in on the receiver of the other with the two radios side
by side. The signals in both sets were very weak, but readable.
Following this, the SCR-610 was moved to successive locations
ranging from 200 yards to 2 & 1/2miles away. Within the
range of 1/4 to 1 & 1/2 miles the two sets operated together satisfactorily
for two-way communication without retuning the Type
94 Mark 6. After the initial move to a location 1/4 mile from
the Type 94 Mark 6, however, it was necessary to retune the
Jap set. Communication was sporadic at distances from 1 & 1/2
to 2 & 1/4 miles.
.
Installed in a command car, the SCR-608 was operated from
a stationary location, while the Type 94 Mark 6 was carried
in a truck. The signal transmitted by each set was tuned in on
the receiver of the other with the two radios side by side. The
signals in both sets were loud and clear.
.
Tests were conducted by moving the Jap radio to successive
locations 200 yards to 5 miles away. As was the case with the
SCR-610, retuning was necessary after the initial move. Within
the range of 1/2 t o 4 & 1/2 miles, the two sets operated together
satisfactorily, with tuning very critical. Beyond 4 & 1/2 miles
communication was sporadic and subject to interference from
adjacent channels. The signal from the Type 94 Mark 6 was
not strong enough to operate the “squelch” x of the U. S. set
beyond 1/2 mile.
.
Two flat No. 4 batteries for filament and-six Type B-18 batteries
for plates—the batteries delivering 3 and 135 volts, respectively—
are used by the Japs for the Type 94 Mark 6.
.
These batteries fit in the battery box of the radio set.
.
If Japanese batteries are not available, the set may be operated
with two Signal Corps BA-23 and six Signal Corps BA-2
batteries, all of which will fit in the battery box except one
1 “Squelch” refers to the stoppage of ‘oscillation.
.
page 26
.
BA-23. The extra BA-23 may be carried in the headset pouch
attached to the battery box carrier. For reduced weight the
BA-23 batteries may be replaced by four or six BA-30 batteries
connected in series parallel to give 3 volts, although this
will give shorter battery life.
.
Due to a shortage of the Japanese UZ-30MG tubes used in
the Type 94 Mark 6, it may be necessary to perform a field
conversion so that Type 19 or similar U. S. tubes can be utilized.
.
Because Japanese microphones and headsets are of
rather poor quality, it is also recommended that U. S. Type
T-17 or similar microphones and U. S. Type HS-30 or similar
headsets be adapted to replace them.

2) History of Technical Intelligence Southwest and Western Pacific Areas 1942 – 1945 (Vol. 1 of 2) US Army Technical Intelligence Center, Accessed from US Army Combined Arms Research Library, Digital Library

Victor 4 Operation — Zamboanga, Mindanao; 41st Infantry Division
Page 101 of 157 (Page 90)

Lt Ford found that the Japanese type 97 portable wireless
telephone set could receive signals clearly from U. S. frequency
modulated SCR-610 end SCR-300 sets at distances of 2300 to
3000 yards. This was important, as messages in the past had frequently
been sent in the clear on these two sets. The 41st
Division Signal officer, the G-2, and the Division artillery
were given this information.

Victor 2 — Cebu: Americal Infantry Division
page 105 of 157 (page 94)

Though no new Ordnance equipment was recovered, fourteen very
high frequency directional radio transmitters having the same frequency
bands as the Unites States VT fuzes were captured near Cebu
City, These sets were inspected by T/3 Borchers (Signal) and
arrangements made in conjunction with the Ordnance and Signal
officers of Eigth Army Headquarters to have the radios tested in
the field with actual AA firing to see if VT fuzes could be
activated by waves from these sets, since this would prove an
effective counter-measure against United States weapons.

3) See this link, and placed it in Google Translate:

http://n-mmra.net/radio/94-6/94-6.html

And see this Wikipedia link on the US Army SCR-610 radio:

http://en.wikipedia.org/wiki/SCR-610

The SCR-610 covered 27-38.9Mc. Most IJA and IJN radio sets can reach at most to 30000kc, the edge of VHF radio band. However, the Japanese Type 94 Mark 6 walkie-talkie frequency range was 25000kc – 45500kc, covering those of the SCR-600 series FM radios.

4) This is clipped from the Signal section of the Luzon After Action report of the XIV(14th) Corps showing that the idea of FM communications by the Japanese was not thought possible and the security issues with Army troops thinking that FM voice radio was inherently secure–

HEADQUARTERS XIV CORPS
APO 453
AFTER-ACTION REPORT
M-1 OPERATION
PART II
ADMINISTRATION

Page 50

f. In the BATANGAS area there were reports of Japanese voice radio transmissions from operators of an artillery F.M. radio set of the SCR600 series. A sensitive monitoring receiver (BC-787) was set up at an, elevated spot in CANLUBANG end the intercepted traffic was piped into a loudspeaker in the Lang-age Section of AC of S, G-2, at CorDs Headquarters. Intermingled with our own artillery radio traffic, numerous Jap voice signals were heard and translated by Nisei at the headquarters. It was noted that such transmissions were only intercepted between, 1100/I and 1800/I, with the signals best about 1330/I on frequencies ranging between 26 megacycles and 38 megacycles, indicating that the stations were at a great distance (over 1200 miles). Translation of the Japanese heard revealed that the nets were of the Air-warning and Air reconnaissance type, some of them being on a training status, while others seemed to be reporting the approach of hostile (American) aircraft with reference to some of the larger cities in Japan itself, verifying the suspicion that the Jap nets heard were most likely not in the Philippine Islands.

and

Page 56

(3) Security in the M-1 Operation was only fair because too many voice operators (especially on Air-ground radio sets) are not security conscious. There is some idea that FM has a security feature. This is entirely false. Officers seem to be the worst offenders on voice radio. During the practice landings, by intercepting voice radio nets of ground units, it was an easy matter to reconstruct the complete order of battle. This led to the schooling of our people in increased use at brevity codes and careful message writing. On CW circuits, where most traffic is usually enciphered, security was very good; what few breaches of security rules there were came from clear text and/or improper procedure between radio operators.

5) This is the transcript of the PBS Show “Victory in the Pacific” that includes an interview of an Okinawan Student Conscript carrying suicide bombs to Kakazu Ridge the night before the failed 193rd Tank Battalion/105th Infantry Regiment attack.

http://www.pbs.org/wgbh/americanexperience/features/transcript/pacific-transcript/

Donald Miller: They went in on April 1 and they thought: What is this? An April Fool’s joke? “Where are the Japs?” We got all this big buildup on the boat. And they told us about the ferocious snakes and the Japs are worse than the snakes, and we’re going in there and it’s going to be maybe the final battle. Then there’s nobody on the beach?

Narrator: For five days, American forces were unopposed as they headed south. An admiral radioed Chester Nimitz, Commander of the Pacific Fleet, “I may be crazy, but it looks as if the Japanese have quit the war, at least in this sector.”

Donald Miller: And Nimitz wired back, “Delete everything after ‘I may be crazy.’ ”

Narrator: General Mitsuru Ushijima could smile from his mountain headquarters beneath ancient Shuri Castle. He was luring his enemy into a trap.

Donald Miller: Ushijima was very smart. He followed a theory the Americans called it the “cornered rat” theory. Terrain’s everything here. And the southern part of the island, the terrain explains it, a series of ridges in the south. So he builds steel, concrete, and coral garrisons inside the mountains. So he has two things that you need to win a battle. He has concealment, and he’s got the advantage of height.

Narrator: The first major line of defense was at Kakazu Ridge. Ushijima’s command post was under Shuri Castle four miles south in the main line of defense. These ridges ran the width of the island. There were no open flanks. The Army’s commander decided to storm the ridges.

Jerome Connolly: You got up every morning, and there’d be another craggy, rock-piled hill and the Army, infantry, would take off over whatever open ground there was. The Japs would then lay into them, and we’d try to keep them down with our machine guns. And that was like a continuum. Every day it was the same story, only different guys got hit and different guys got killed, I used to look at those infantry guys go across — go across those fields. God, it’s tough to believe.

Narrator: The Army sent in tanks.

Katsuo Nagata, Okinawan Student Conscript: We student conscripts were ordered to deliver bombs to Kakazu for destroying U.S. tanks. We carried 10 kg bombs on our shoulders and headed for Kakazu at night. The Americans launched a star shell and then came the gunfire. We had to hide in the shade whenever a star shell was up, but finally we managed to deliver the bombs to Kakazu. I heard that, the next morning when the tanks came, they armed the bombs and made suicide attacks into the tanks.

6) UNITED STATES ARMY IN WORLD WAR II, The War in the Pacific, “OKINAWA: THE LAST BATTLE” by Roy E. Appleman, James M. Burns Russell A. Gugeler, and John Stevens, CENTER OF MILITARY HISTORY, UNITED STATES ARMY, WASHINGTON, D. C., 2000, Library of Congress Catalog Card Number: 49-45742, First Printed 1948-CMH Pub 5-1

http://www.history.army.mil/books/wwii/okinawa/chapter8.htm#b2

7) XXIV Corps Okinawa Action Report, 1 April 45 – 30 June 45, dtd June 1945

page 122
.
e. Jap Counter-Intelligence.
.
An outstanding feature of OKlNAWA campaign from the order of battle viewpoint was the dearth of enemy documents and other identification material. Captured orders now make clear that a strenuous security effort which has been carried out by the Commanding General, 32d Army. Diaries were ordered burned and dogtags picked up before units entered combat. In addition, all unit records were ordered to be destroyed or deposited with 32d Army. All Army records were in turn ordered destroyed by the engineer battalion in charge of demolishing the 32d Army Headquarters at SHURI during the withdrawal.

8) “Information on Japanese Defensive Installations and Tactics”, ARMY WAR COLL CARLISLE BARRACKS PA, Report Date: Jan-1945, 37 page(s)
DTIC Accession Number: ADA438611

pg 5

32D ARMY COMBAT DIRECTIVE No. 13
1. The capacity of the enemy’s. M1 tank to cover terrain must not be
disregarded.

We must not neglect the organization of anti-tank positions in areas
believed to have difficult terrain.

For example, between 3 April and 4 April, 5 enemy tanks advanced
against the 62d Division’s KADANI Det’s UGUSUKU (TA: 8781 W) positions.
2. It is increasingly,clear that the enemy’s combat strength is in tanks
and that fighting against the American land army is practically the same things
as fighting against the M1 and M4 tanks.

It is necessary that the construction and organization of positions
be made in accordance with all the above considerations.

page 7

COUNTERPLANS

1. Organize close-in attacks beyond the range (135 meters) of the enemy’s
flame thrower attacks.

2. Prepare several entrances in such a way that they will give mutual
support.

3. It will be most impossible to bring about complete destruction /of
the enemy/doing nothing at all or with all the personnel flinching inside
the caves.

4. Maximum effectiveness is attained with the 47mm AT gun by using.delayed
fire against the ,M-4 type tank at very close range.

Example:
At about 1200 4 April, 5 M-4 tanks (one of them was an M-1) attacked
hill 85 southeast of Oyama (TA: 8179 VW, With 20, rounds of 47mm AT gunfire
they were stopped and set afire, and extensive bat tie. damage resulted*

Successful results are achieved by remaining concealed and through the
use of slashing concealed fire at very close range.

8) The naming conventions of Hawaii built flame tanks depended upon who you talked to in which battle. The USMC and US Navy called flame tanks C.B. Mark-1’s, for Naval Construction Battalion Mark – 1 due to the involvement of Naval Seabees . The US Army’s Chemical Warfare Service and the US Army on Okinawa didn’t use that convention. See:

Appendix 12 to Annex Charlie: Special Staff Section Reports (Ordnance), HEADQUARTERS, V AMPHIBIOUS CORPS LANDING FORCE, -IWO JIMA- Staff Section Reports page (212 of 261) “CB Mk 1”

a. Enclosure H (HOW) Third Marine Division Operation Report Iwo Jima page 532 (22 of 31 in enclosure) “CB-H-1”

b. ANNEX JIG TO FOURTH MARINE DIVISION OPERATIONS REPORT IWO JIMA 4th TANK BATTALION REPORT Page 22 of 24 “CB, Mk1”

c. Major Samuel Littlepage, (713th Flame Thrower Tank Battalion) Observer report titled “Armored operation on Iwo Jima.” 16 March 1945 http://cgsc.cdmhost.com/cdm4/item_viewer.php?CISOROOT=/p4013coll8&CISOPTR=1151&CISOBOX=1&REC=9

page 4

F. Flame Thrower, C.B. M-1.
1. This weapon gave excellent results when it worked and could reach the target. In rubble brush and defiladed positions it caused casualties where no other weapon could reach the target. A typical example of its work was on airfield #1 where it flushed a group of snipers from a pile of wrecked airplanes. When the flame was played, on the pile, the snipers rushed into the open and were killed by machine gun fire.

2. A combination of mechanical trouble and poor fuel reduced the efficiency of these weapons approximately 75%. The average length of flame produced was about thirty five yards while the potential range of the same gun is over 100 yards farther than this.

page 5

3. Of the attempts to use this weapon observed, it failed to function at all 25% of the time.

4. This weapon had never been tested in the field under operational conditions prior its use in combat. The parts were made of salvage material and differ in size from one weapon to another. The construction of these weapons was under ‘very hasty conditions and time did not permit requisitioning ideal materials from the mainland.

5. On one occasion the three-way valve blew out and the crew was very nearly suffocated by Co2. The vehicle was surrounded on three sides by cliffs infested with snipers at that time.

6. Unfavorable winds (completely) rendered the weapon useless on several occasions.

page 6

7. Recommendation.
.
5. Every tank company, should have at least two tankdozers and two large flame throwers.
.
6. The C.B. M-1 Flame Thrower should be thoroughly field tested before it is sent into combat.

Major Samuel Littlepage

Inf (armor)

d. PARTICIPATION IN THE IWO JIMA OPERATION, UNITED STATES ARMY FORCES in the in the PACIFIC OCEAN AREAS, FEBRUARY – MARCH 1945, Lieutenant General ROBERT C. RICHARDSON, US ARMY JR COMMANDING

PART 3 CPBC (Central Pacific Base Command.)

page 181

4. Training.

a. The 271st Chemical-Composite Platoon was trained at the chemical warfare depot at Schofield Barracks, Oahu, in all phases of supply and maintenance of cnemical warfare equipment.

b. One hundred sixty-five officers and enlisted men of the 4th and 5th Marine Divisions were given three days of instruction in defense against chemical attack in a school conducted by the HCPBC (Hawaii CPBC) chemical office. In addition, 16 enlisted men of the 4th and sth Marine Divisions were trained under HCP3C supervision in thier operation, maintenance, and preparation of fuels for the flame thrower (mechanized, POA-CWS, H1-H2).

9) “Jap Artillery in Northern Luzon 9 January to 30 June 1945,” The FIELD ARTILLERY JOURNAL, January 1946, page 17 to 23

This article had no listed author, indicating an offical report of the Field Artillery branch. Please note the post-war narrative difference here and that of the other wartime notes for this column. Significant by its absence is 32nd Army directive No. 13. This may be an issue of the Field Artillery branch authors not reading Army or Marine classified reports due to “Need to know” restrictions, or it may be intentional. Not seeing official mention of this Japanese tactical radio monitoring ability of American FM communications in the official Green Book histories _at all_ can only be described as intentional.

Link:

http://sill-www.army.mil/firesbulletin/archives/1946/JAN_1946/JAN_1946_FULL_EDITION.pdf

JAP RADIO INTERCEPTION AND JAMMING
The Jap had radios that operated on the same frequencies as our own and which undoubtedly could have monitored our nets.
.
There is no evidence, however, that this was done on our artillery channels. Jap voices were frequently heard on our sets and in a few instances interfered with their use.
.
At times there was evidence of a deliberate attempt to jam a channel by constant voice repetition of a given phrase. This interference was generally ineffective in preventing our use of the channel. No case was reported of the Jap trying to interfere with our fire missions by entering the net with false sensings or commands.