Japanese weaponry
When it came to weapons production, the Imperial Japanese Army’s requirements often came in second to the needs of the Imperial Japanese Navy. The Army was an infantry-heavy organization that lacked much in the way of the modern heavy weaponry other armies enjoyed.
To help compensate for the lack of heavy weapons, the Imperial Japanese Army worked hard to develop large numbers of what were probably the best light infantrymen in the world at the time. Their creed stressed relentless offensive action seeking a quick decision and emphasizing spiritual factors including zealous dedication and fighting spirit. Night attacks were a true specialty, and their weaponry reflected their light and fast doctrine.
To offset their frequent lack of artillery, the Japanese augmented their firepower through the extensive use of mortars, the best and most cost-effective substitute for industry-intensive heavier artillery. Technically, Japanese light “knee” mortars at first merely bridged the gap between hand grenades and true mortars and were more properly referred to as grenade dischargers.
The Model 89 was by far the most prolific of the grenade dischargers and the weapon most commonly encountered by Allied Marines and soldiers throughout the various theaters of the Pacific War. Technically known as the Hachikyu Shiki Jutekidanto, or 89 Model Heavy Grenade Discharger, the new weapon featured a wide variety of improvements over the old Type 10 and had almost universally replaced the former weapon by 1941. To the frontline Japanese infantryman, the Type 89 was most often referred to as the Juteki.
To fire, the gunner removed the fuse’s safety pin and dropped the bomb tail first down the muzzle of the knee mortar. A pull on the leather lanyard attached to the trigger then fired the weapon. The firing pin struck a percussion cap primer that fired the propelling charge, which also caused a copper driving band on the charge body to push out and engage the rifling of the barrel. The force of discharge also set back and armed the fuse in the nose projectile and re-cocked the mainspring inside the mortar. This was usually done at a 45-degree angle.
Despite these relatively crude controls, a soldier could quickly and easily be trained to fire the Type 89 knee mortar with impressive accuracy. While it could be fired by one man, a knee mortar with a three-man crew could maintain an effective rate of fire of 25 rounds per minute.
Lt. Col. Merritt “Red Mike” Edson, leader of the famous Marine Raiders, critically evaluated the knee mortar and insisted American forces badly needed an equivalent. He listed the following reasons:
“1. It is a one man load.
2. A man can carry ten rounds on his person besides his weapon.
3. It has a high rate of fire.
4. It gives to the platoon commander a weapon of this type which is immediately available to him.
5. This mortar uses the Jap all-purpose hand grenade….”
A Marine Corps legend, then-Lt. Col. Lewis “Chesty” Puller seconded Edson’s opinion. “I consider it imperative that the Army and Marines be equipped with knee mortars and only carry one type grenade.”
Army Sergeant C.W. Arrowood completely agreed: “The Jap knee mortar gives us hell. They come in fast, thick, and accurate. Can’t we have one?”
The answer to Sergeant Arrowood’s question was a resounding No. United States forces soldiered on with the little loved rifle grenade until the advent of the M79 40mm grenade launcher during the early stages of the Vietnam War.
References: Warfare History Network;
Click on images to enlarge.
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Military Humor –
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Farewell Salutes –
Cecil Akigg (100) – Calgary, CAN; RC Army, WWII, ETO, radar technician
Nicholas Baxter – Harrisburg, PA; US Army, Co. M/187th/11th Airborne Division
Benjamin Bold – Rotorua, NZ; NZ Army # 267128, WWII, Pvt., J Force
Jean Doyle – Tyngsboro, MA; US Army Air Corps WAC, WWII, 1st Lt.
Luther Gordon – San Diego, CA; US Army, WWII, ETO, Purple Heart, Silver Star
Melton ‘Dale’ Hair – Tulsa, OK; US Navy, WWII
Herschell Johnson – Dothan, AL; US Army, WWII, ETO, 8th Armored Division
John Kelly Jr. – Billings, MT; US Navy, WWII
Richard Pettijohn – Naples, FL; US Army, WWII, ATO, radio operator
Gordon Sherwood – Yarmouth, ME; US Army, Korea
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Posted on January 29, 2018, in WWII and tagged 1940's, Army, family history, History, Japan, Marines, Pacific War, USA, veterans, Weapons, WW2, WWII. Bookmark the permalink. 91 Comments.
Reblogged this on Ancien Hippie.
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Thank you for sharing this.
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I saw a lot of these during my trip to Mount Samat, Bataan. It’s fascinating. It would be better if someone would explain how the weapons work though.
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I hope you don’t mean to try one of those you saw! but here you go… A Grenade Launcher (GL) is much like a light infantry mortar. The round
is like a large bullet, with the projectile and the launching charge
contained in a single unit. The launcher is like a pistol with a light
mortar barrel.
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You are amazing. I did not see that coming. I just hope you were the one who manned the war museum that time. I’m sure you’ll be able to discuss the weapons there thoroughly. Thanks for the answers, I can somehow picture in my mind how the weapons I saw back there worked. Two thumbs up! 😉
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No problem.
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I knew only a bit about this weapon. Your article piqued my curiosity; I took this excerpt from Wiki – (they produced this nasty device in 1932!)
When fired from the Type 89 discharger, the Type 91 fragmentation grenade was fitted with a propellant base and time fuse. It did not explode upon contact, but was designed to ignite its fuse while in flight. A weak creep spring inside the grenade firing mechanism allowed the firing pin to be thrown back upon launching, igniting a time fuse with a 7-8 second delay. Using this system, the Type 91 grenades could be launched through jungle cover or through small openings without the danger of premature detonation in the event the grenade struck an object on its way to the target. Although the Type 89 could be fired by a single person, it was typically operated with a crew of 3, enabling it to reach a rate of fire of about 25 rounds per minute.
https://en.wikipedia.org/wiki/Type_89_grenade_discharger
Good posting, GP.
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I love hearing that I piqued someone’s curiosity! That is my goal – especially since our school systems are dropping the ball.
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How is you 😀
I found a perfect IMAGE which is perfect Naughty on my the end of the month blog.
Chuckle,plz…XD!!!
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GP, Thanks for visiting my website today…..causing me to take a look at your latest here. I lucked out reading & fascinated by this piece on the Japanese mortar, more accurately Type 89 knee mortar. I could really identify with this. Our basic training in the Vietnam era included training in firing mortar launchers.You said here how the knee mortar was amazingly accurate. But we couldn’t hit the tank put out on the firing range for us as practice with the mortar launcher!!! You can’t underestimate the skill of the Japanese besides the accuracy of the weapon. Great piece of writing, GP! Phil
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I don’t think we copied it exactly the same either. Thanks for stooping in, Phil.
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That was truly interesting, GP. I liked seeing the diagrams too. Have a wonderful Wednesday. Hugs.
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Thank you very much, Teagan. It’s good to know that all this info is of interest to people.
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Succinct article GP – I’ve not heard of a knee mortar before seeing this post.
Thank you – keep ’em coming.
I meant, the weapons articles – not the mortar grenades 🙂
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lol, good one, Eric, and thank you for the encouragement!
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They should have listened to the sarge, the man in the field, he knew what was needed, trouble with bureaucrats and pen pushing desk officers
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NOW _Isn’t THAT the truth!! haha
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No one ever listens to the guy in the field…
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Actually, the men knew if they could get to MacArthur, he would be the first to listen to them, but that doesn’t apply here.
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Reblogged this on Give Me Liberty.
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I was unable to locate it, so I presume you have it in drafts. I hope the readers find it interesting when it is published.
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I am not sure how true it is but I read or heard about American GI’s taking the knee mortar name at face value and getting broken legs as result of trying to fire them from their knees
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I do believe that to be true, but I have seen it done – sure wouldn’t want to do it too often.
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Ondanks ik helemaal niet van wapens houdt geef je hier toch hele goede uitleg
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Thank you. I wanted to show what our men were up against.
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I had to laugh part way through it. The Colonel quite the way you do!! Thanks for adding all that and taking the time!
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P.S.
Don’t publish this comment here. It’s unrelated to Japanese weaponry.
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I’ll copy it any put it on Chick Parson’s post.
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Great post! The zealous dedication part about the Japanese was especially interesting!
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They were excellent soldiers with loyalty and dedication. This weapon was a great help to them – awful for us and should have been copied. Thanks for dropping in, Jacqui!
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That’s for sure! You are welcome!
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Interesting. We certainly underestimated the Japanese in the early days of WW2 – and I wonder how much a lack of respect for your enemy is behind an unwillingness to learn from them?
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Big egos, obstinance, red tape – any number of things. Sometimes we learned and other times…..
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There is an excellent PBS program on the development of radar (also, a critical weapon during WWII). It’s called “The Secret of Tuxedo Park”. You can find details at: http://www.pbs.org/wgbh/americanexperience/films/secret-tuxedo-park/.
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I’d heard of Tuxedo Park, but never knew the details. I skimmed the transcript and sign up for the newsletter, so I will get back to it. Thank you very much, Anna.
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This is a really awesome post, very informative and interesting!
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Thank you very much, Mike. I appreciate that.
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What a disservice to our troops to keep better equipment from being developed.
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They were always developing ‘new and improved’ equipment, I suppose they wanted it to be their idea – not the enemy’s. I see it as obstinance.
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Informative and interesting gp, never heard of the knee launcher before, my only experience has been Mortars with base plate and the M79 Grenade launcher
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Being in Vietnam yourself, you know exactly what this article talks about, despite never using the knee launcher. Thank you for reading this, Ian!
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Reblogged this on John Cowgill's Literature Site.
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Much appreciated, John.
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Glad to pass it on.
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I did not know!!
Thank you for your time and effort.
You’re awesome. 😀
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I thank you for your confidence, Nasuko. None of us are too old to learn something.
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Wonder what kind of a kick that had and why my knee is hurting, G… –Curt
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If you’ll notice, the Japanese soldiers had it resting on the ground. I think that may answer the question, haha.
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🙂
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Very interesting… a nice inside look at Japanese weaponry. “It gives us hell… can’t we have one?” Ha 🙂
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Exactly! Was it obstinance or red tape that said NO.
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An interesting look at an amazing weapon. Thanks, GP.
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Thank you, John.
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🙂
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The political infighting in the Japanese military was astounding. Had the Imperial Japanese Army and Navy brass cooperated and not competed, their impact on the Pacific may have been even more powerful than it already was. Some of the equipment issues that the IJA had was puzzling. Their tanks were quite frankly terrible. Designs were for extremely light infantry support vehicles like the 7.4 tonne, type 95 Ha-Go, was not even a match for British M3 Grants in the ’44 Burma campaign. Many such examples exist, not least the IJA and IJN persisting with obsolescent aircraft designs as the Allies overtook them in the Pacific theatre (I know they had great aircraft like the Ki-61, Ki-84 and Ki-100, but these weren’t available in anything like the numbers needed). I think the attitude of the Japanese commands of both the Army and the Navy was that the Japanese soldier was their best weapon. They were quite right in that respect. But every soldier, no matter how well trained and motivated needs equipment. Great post GP.
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Thank you very much. I agree with everything you’ve said. I can not imagine what would have occurred if the army and navy had worked together (and to think Tojo controlled them both!) His generals and admirals ultimately were one cause for their defeat.
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Thank you, thank you once again.Appreciate remembering….to be kinder and wiser.
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I wish people would learn from you! Thank you.
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It’s the OTHER blog I write other than Pioneers of Aviation (https://av8rblog.wordpress.com/). Thanks for your support with Pioneers. It is long appreciated!
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Thank you.
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Hey GPC, I posted the URL to your article on Japanese weaponry on my blog (http://wonderfulrife.blogspot.ca/2018/01/japanese-weaponry-of-wwii.html). Nice job, brother! AJ
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Thank you. I hope it will be helpful for those who are interested.
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I tried to comment on your site, but it kept blocking me.
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Very interesting psychology. Incite into their war strategy.
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Isn’t it though! Adopting this weapon would have simplified the soldiers’ lives – I guess that was the problem! 🙂
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Very interesting post!
If you focus on the design (an ignore what is happening to the people on the receiving end), military technology is fascinating. It’s hard to fathom why the War Dept didn’t jump on this knee mortar. They did some things, like the DUKW, with amazing speed.
I guess sometimes the speed of adoption is a matter of necessity and limited resources, like the Rhino hedgerow cutters welded onto Shermans in WWII, or the “hillbilly armor” for our trucks in Iraq. The Germans in WWII were quick to adopt Czech tanks, and pistols from Poland, Belgium, etc.
One of my grandfathers mentioned once that when it was his turn to carry a mortar base plate on a hike, that made for a very long day. He would have loved this little one.
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I’m sure your grandfather would have jumped at the chance for this one – you can see how simple. The War Dept. had it’s own crew working on new materiels, just as Smitty explained with the tents, haha. They didn’t think about the engineering on those either, but maybe they were insulted to have the Japanese outdo them on this.
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I don’t know much at all about weaponry, but I know enough about bureaucracies and pecking orders to know that, in this case, the power of the bureaucracy outgunned the power of the weapon. 🙂
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Very well put, Linda!! 🙂
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Reblogged this on Die Erste Eslarner Zeitung – Aus und über Eslarn, sowie die bayerisch-tschechische Region!.
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Thank you, Michael. It helps to show what the Allies were up against.
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An enlightening post about war in the Pacific with engaging visuals.
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Thank you. Often the pictures explain more than I do.
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red tape is right!
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🙂 🙂
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Since the beginning of warfare great army leaders were willing to learn from their enemies. Here is just one example. The Roman Navy in the early stages of the Punic War with Carthage was vastly inferior to the enemy’s warships. When one of the enemy’s ships got shipwrecked off the coast of Italy, Roman engineers studied its structure and copied the design and built vessels for their fleet that matched the strength of the Punic navy. So it is astounding to read that the Japanese knee launcher was not copied and built for the American infantry men.
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Bureaucracy or red tape?
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Peter:
Not at all. What profit was in it for the politicians who made the decisions or the manufacturers who’d have had to retool? So why is it surprising that a few grunts were expendable to maintain the status quo (after all, the draft, and a steady stream of youngsters coming on line …)?
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The Army trained its new advisors arriving in Vietnam on almost every infantry weapon available because they didn’t know what the man would find when he arrived at his assignment. When I hit the steel target three times in a row with an M79, you can imagine my delight when it fell from its supports — of course there had been thousands of soldiers hitting it before me.
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But you got it to fall!!
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That’s an interesting look at a weapon that was indeed versatile, and very useful for front-line troops. Army procurement is notoriously tardy in adopting new weapons in most countries, and suggestions from combat soldiers have been routinely ignored.
During WW1, it soon became apparent that companies at the front should have many more heavy machine guns. The German successes from using many more HMG than the allies proved this to be the case. But it never happened.
Best wishes, Pete.
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Just goes to show you the power of red tape, eh?!
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Pete:
How about if the guys evaluating from behind were to be shipped pronto to the front to see at first hand?
Would that have made any difference at all, do you think?
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For sure it would have!
Best wishes, Pete.
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I so appreciate your help!
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Thank you, Ian!
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Thank you, Ian.
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