This thread is another visit into the pyrrhic victory known as Operation Iceberg, the Apr 1945 invasion of Okinawa.

This thread is based on my Aug 2013 Chicagoboyz column "Technological Surprise & the Defeat of the 193rd Tank Battalion at Kakuzu Ridge"
chicagoboyz.net/archives/38455…
1/ XXIVth Corps 19 April 1945 situation map showing the 27th InThis is the wreck of a M4 Sherman tank on the approaches to
On 19 April 1945, the US Army’s 27th Inf Div launched an attack against the Kakuza Ridge position held by the 32nd Army on Okinawa with the 193rd Tank Btn's 30 tanks, S.P. assault guns, and attached armored flame throwers from the 713th Flame Tank Btn.
2/ This is a 713th Flame Tank Battalion M4 Sherman rebuilt as a
When the battle was over, 22 of the 30 AFV had been destroyed in a coordinated ambush by Japanese AT- guns, artillery, mortars & suicide close assault teams. Among the dead was the commander of the 193rd, on whom blame was laid for attacking without infantry in close support.
3/ This is a detailed Fire Plan Map of the Imperial Japanese ArThe commander of the 193rd TB had a great deal of faith in tThis is the description of the Sherman "backscratcher&q
After the catastrophe at Kakuzu Ridge, th 193rd TB was effectively disbanded & their remaining tanks were used as replacements by other US Army TBs.

This battle is referenced in most narrative account of Okinawa as proof of the tougher defenses US soldiers and marines
4/ Mines are not your friend.
...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

Reversing Churchill, this narrative has a huge lie buried in a bodyguard of truth.
5/
The most important truth of this battle was that US troops suffered a technological surprise. The IJA were listening to the SCR-300, SCR-500 and SCR-600 series FM radios of US infantry, tanks and artillery forward observers at Kakuzu Ridge (& other battles through out the
6/
Pacific in 1945) with Japanese Type 94 (1934) Mark 6 walkie-talkie radio that was issued to every IJA Inf. btn.

US tanks were equipped with FM radios & their operators were told the IJA didn't have any FM gear & took no security precautions.
n-mmra.net/radio/94-6/94-…
7/
The poor performance of the 193rd Tank Btn on Okinawa at Kakuzu Ridge could be easily explained if that were the case.

So, serious charges require serious proof. Where's the proof?

"Show me the money!"

8/
This is the transcript of the 2005 PBS Show “Victory in the Pacific” that includes an interview of an Okinawan Student Conscript Katsuo Nagata who carried 10kg suicide bombs to Kakazu Ridge the night before the failed 193rd Tank Battalion/105th Infantry Regiment attack.
9/
So, the night before the 193rd TB's attack, the IJA independent 272th Inf Regt. knew US tanks were coming, check.

Where is the proof the IJA was using it's Type 94 (1934) Mark 6 walkie-talkie radio to monitor & exploit US Army radio communications?
10/
First let look at IJA radio via History of Technical Intelligence SWPA 1942 - 1945 Pg 90

"Lt Ford found that the Japanese type 97 portable wireless telephone set could receive signals clearly from US frequency modulated SCR-610 & SCR-300 sets at distances of 2300
11/
...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."

The capabilities of the type 94 walkie-talkie radio were
12/
...noticed in Luzon as well.

Intelligence bulletin. Vol III, No 12, Aug 1945 issue, noted that:

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

cgsc.contentdm.oclc.org/cdm/compoundob…
13/
...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 tests show that the enemy sets operate satisfactorily with the

14/
...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"

The article also detailed how to covert & maintain the IJA Walkie-Talkie with US Army batteries & vacuum tubes!

15/
So, the IJA had both radio means (link) & the motives. How do you prove the IJA about used its opportunities?

To understand this, you need to become familiar with the US Army vs USMC naming conventions for M4 Sherman main armament flame tanks.

lonesentry.com/manuals/handbo…

16/
The USMC called it's Iwo Jima M4 Sherman main armament flame tanks "C.B. Mk-1" AKA Construction Battalion Mark One.

Over the radio it was simply "Mark One"

17/
The US Army Chemical Warfare Service used a complicated designation that was more abused than used. It runs as follows:
Flamethrower, mechanized, main armament, CWS-POA "75" H1-H2

CWS - (see above)
POA - Pacific Ocean Area
"75" H-1 - See CB-H-1 Gun
H-2 - See fuel tanks
18/
Now we turn to IJA General Mitsuru Ushijima (same man both uniforms)

Ushijima issued 32D ARMY COMBAT DIRECTIVE No. 13. Which was captured, translated and reprinted in “Information on Japanese Defensive Installations and Tactics”, ARMY WAR COLL CARLISLE BARRACKS PA.
20/
Ushijima directive (see text clips) came out after the US landings but before Marines used flame tanks in Southern Okinawa.

The 10th Army & XXIVth Corps Army units never called flame tanks "Mark One's"

So where was Ushijima getting "M-1" in DIRECTIVE No. 13 ?

21/
The only answer that works is that the IJA garrison on Iwo Jima heard USMC tank crew in the clear over their FM radios. Then the garrison there passed that information to Japan.

After reviewing IJA GHQ passed the intelligence to Gen Ushijima's 32nd Army staff.
22/
This brings up very difficult historical questions for the last year of the Pacific War starting with Navajo code talkers at Iwo Jima.

While they were a safe code there...

...they were not EVERY CODE at Iwo Jima.

23/
How many US Marine infantry attacks were anticipated by Lieut. Gen. Tadamichi Kuribayashi's garrison because they were listening to USMC tankers talking in the clear on FM radios they thought secure?
24/
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
25/
...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.
/End

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More from @TrentTelenko

12 Jun
This is a short thread on Japanese bulldozers in WW2.

There weren't many & they were small

My copy of Rikugun. Volume 2: Weapons of the Imperial Japanese Army & Navy Ground Forces 1937 - 1945 does not show a single Japanese bulldozer design.
1/ Image
There are a few hints about them on the internet.

In December 1942, the Imperial Japanese Navy commissioned Komatsu to produce heavy earthmovers for the purpose of building air bases.

See this link -- kenkenkikki.jp/museum/bulldoz…
2/ Image
Only 148 of the 5,000 kg Komatsu bulldozers were produced by the end of the war. Some were sent to the Philippines to build air bases

And note "Heavy" by Japanese standards compares to the 23 tons of a US D-8 bulldozer of 1943 vintage.

en.wikipedia.org/wiki/Caterpill…
3/ Image
Read 6 tweets
11 Jun
@adam_tooze @gideonrachman A UH-60 Blackhawk has a radius of action of 368 miles with external stores system fuel tanks.

The Chinese have copied & improved on this helicopter as the Z-20.

It is 130-ish kilometers in the closest Chinese coast to the closest Taiwan coast.

thedrive.com/the-war-zone/5…
@adam_tooze @gideonrachman The Z-20 has a 5-blade rotor system and more powerful engines as well as auxiliary wing-like hardpoints attached to it, similar to the Lightweight Armament Support Structure (LASS) and External Stores Support System (ESSS) wings on the US Blackhawks.

thedrive.com/the-war-zone/3…
@adam_tooze @gideonrachman Essentially, a fleet of Z-20's with external stores can do 2 round trips from Mainland China to Taipei loaded with 11 troops per lift.

Or they can trade fuel for weapons and play assault gunship to support infantry air-landings.

A Chinese coup de main vs. Taiwan is now possible
Read 4 tweets
10 Jun
@ArmouredCarrier @NaomiClareNL @AC_NavalHistory @Drachinifel @CIMSEC @CIMSEC_UK Electronic warfare is an attritional form of warfare.

The firestorming of Hamburg due to RAF Bomber command use of an early form of chaff, code named 'Window', did not end WW2.

The Luftwaffe adapted & a few months later "defeated" them over Berlin.

en.wikipedia.org/wiki/Bombing_o…
@ArmouredCarrier @NaomiClareNL @AC_NavalHistory @Drachinifel @CIMSEC @CIMSEC_UK A few months after that , RAF 100 Group developed a suite of EW tactics and suppressed Luftwaffe C3I for night fighters & flak. Image
@ArmouredCarrier @NaomiClareNL @AC_NavalHistory @Drachinifel @CIMSEC @CIMSEC_UK This is a chart of the RAF Bomber Command loss rates keyed to when various electronic warfare devices and techniques changed. Image
Read 4 tweets
9 Jun
Alright, since the Bilge Pumps episode 52 is up, and I really didn't get a chance to go deep with US military 3D printing as is, versus what I see coming.

I'm going to drop a background thread here to do just that.

Note: long thread warning
1/
the-bilgepumps.simplecast.com/episodes/bilge…
3D Printing/Additive Mfg has been around for a while.

The four “foundational” patents for 3D/AM processes were issued one each in 1984 and 1986 with the remaining two in 1989.

Two National Science Foundation impacted 3D/AM patents were issued in 1987 and 1995. (See photo)
2/
RAND in 2017 identified seven different 3D/AM Processes for seven material classes.
3/
Read 31 tweets
8 Jun
This is a thread on Normandy/Overlord airpower, signals & invasion stripes.

There was a neat post by @militaryhistori about D-Day to D+1 airpower talking about how many aircraft sorties the Allies racked & stacked over Normandy 6-7 June 1945.


1/
I replied to it with four photo captures of how the airpower flew during the daylight hours of June 6, 1944.

It was a whole lotta planes!


2/
I wrote a thread dealing with all of the above over on the Chicagoboyz blog on 2019's 75th Anniversary of D-Day here:

How Allied Planes Got Their D-Day Invasion Stripes and other "Retro-High Tech" Secrets of the Normandy Invasion
chicagoboyz.net/archives/59917…
3/
Read 45 tweets
5 Jun
Paul Woodage's [@WW2TV] had a very nice video stream today with Kevin Hymel using information from his forthcoming book on Gen Patton.

This thread will expand on a piece of it regards Operation Huskey's friendly fire incident that killed 400 troops
1/
Operation Huskey's 2nd set of air drops resulted in 23 C-47 & C-53 troop carriers, & some gliders, being shot down with 400 US & UK paratroopers plus air crew aboard them. 
2/
amcmuseum.org/history/a-very… Image
The friendly fire incident was due to the lack of a plan for centralized control of fleet and the just landed shore based anti-aircraft weapons.

The Report of Allied Force Airborne Board on Operation “HUSKY” is online (link)
fold3.com/image/1/270149…
3/
Read 13 tweets

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