Jump to content

Recommended Posts

Posted

Hi,

 

I've noticed a lot of you guys are making armour, so I thought this would be a good place to ask:

What modern Steel is the best equivalent for ancient Japanese steel? I've got some papers analysing impurities, but I have no clue about modern industry steels, which comes closest to the historical stuff.

WhatsAppBild2023-07-18um07_54_34.thumb.jpg.346507c2c91779f97779fc06d1482736.jpgWhatsAppBild2023-07-18um07_54_35.thumb.jpg.0a93d6c67ce3273ad24b9622795f14d0.jpg

EDIT: These are parts per million, Carbon content was around 0.3% down from likely 3% in the raw material

(these are samples for the Nara- and Heian-Period, I am going for a Kofun-Helmet I want to reproduce, thats the closest analysis I found. I've found also tables for newer material, that changes a bit of course, but the general gist of high Titanium, Aluminium and Nickel stays the same.)

 

Probably the best would be Tamahagane? But buying 30kg of Tamahagane is out of question, I guess most of you also haven't won enough lotteries, so what do you use?

 

Florian

Posted

Florian,

these old alloys are not available here, as the ores are from Japan. The mentioned elements are just impurities and do not influence the properties of the metal very much. TAMAHAGANE is not a standard material but raw iron with differing composition, especially in the C content.

In KOFUN times, cast iron with high percentage of carbon was not known, so it must have been an early bloom iron with a very low content of C. 

What you want to use is iron with high ductility properties such as deep-drawing sheet metal (Tiefziehblech in German). This is used in car bodies, so you should be able to get it from a scrap-yard. You need a low carbon content to make the material easily workable.

Posted

Agreed. You can get tamahagane, but it's very expensive. For armour, mild steel is a reasonable alternative. You're just going to lacquer it with urushi anyway!

Posted

Before people get too carried away here, here is some actual data on Kofun stuff.

Here's an analysis of the metallurgy in one example, showing the presence of ferrite.
image.png.7ff7444e0eff46af3e3a5512d2f73a63.png


Experimental Archeology Recreating Iron/Steel using recreated Kofun-period methods:
https://www.pref.hir...imin/tenji-tetu.html

 

東アジアにおける武器・武具の比較研究 - Comparative Study of Weapons and Armor in East Asia
(This one includes illustrations of many surviving examples, showing every major variation and in most cases includes a size scale)
https://repository.n...767/1/BA87922583.pdf
 

弥生時代と古墳時代の軍事組織と社会 - Military organizations and society in the Yayoi and Kofun periods

https://ir.soken.ac.jp/record/5475/files/A1859本文.pdf

 

小札鋲留衝角付冑の変遷と その意義 - Transitions in Kozane Byodome Shokaku-tsuki Helmets and Their Significance

https://rekihaku.rep...kyuhokoku_173_07.pdf

 

埼玉将軍山古墳出土の馬冑 - Horse helmet excavated from Saitama Shogunyama Kofun
https://sakitama-mus...616d6b2?frame_id=313

 

一京都府木津町瓦谷古墳出土の - Excavations from Kawaradani Kofun, Kizu-cho, Kyoto Prefecture

http://www.jssscp.or...numbers/vol27_3s.pdf

 

古墳時代における軍事組織について - The Archaeological Analysis of Military Organization in the Kofun Period
https://rekihaku.rep...kyuhokoku_110_09.pdf

If you need anything else, please let me know.


 

 

  • Like 1
Posted

I prefer to use the therm ‘iron’ when it comes to the material used for kabuto, simply because ‘steel’ is less practical to hammer in a certain shape.

but this is a very subjective approach after all.

Posted

Luc, the only difference between "wrought iron" and "steel" is that the iron has layers of silaceous impurities between the layers of steel. A blank of the same thickness of either material, assuming it hasn't been hardened, will be exactly as difficult to hammer as the other. This isn't subjective, it's a reality of the material. If you find any steel to be hard to hammer, all you have to do is anneal it; heat it up to red heat with a propane torch, and let it slowly cool in the air, and you will find it easy to hammer. 

  • Love 2
  • Thanks 1
Posted

Carlos,

if I may correct you: There is a big difference between wrought iron and steel when you work on it in a forge. When I am holding forging workshops for beginners, I usually let them start with iron, as it is much easier to work with. As soon as you have your own forge working, I'd like to encourage you to forge a knife blade out of an old file! It is not only considerably harder to move the metal, the temperature "window" for working it is much smaller!

The effects of annealing are more apparent in cold state; if you heat up iron or steel, it will become more or less ductile.

In Germany, we have changed the use of the terms: Iron is the chemical term for Fe metal. All iron-alloyed metals are now called steel, so we have hardenable steel (with carbon content usually exceeding 0.5% in praxi) and steel with so low a carbon content that it cannot be hardened.

I have always preferred the old use of iron (meaning not hardenable) and steel (hardenable because of its C-content).   

  • Like 3
  • Love 1
  • Thanks 1
Posted
27 minutes ago, ROKUJURO said:

Carlos,

if I may correct you: There is a big difference between wrought iron and steel if you work on it in a forge. When I am holding forging workshops for beginners, I usually let them start with iron, as it is much easier to work with. As soon as you have your forge working, I'd like to encourage you to forge a knife blade out of an old file! It is not only considerably harder to move the metal, the temperature "window" for working it is much smaller!

In Germany, we have changed the use of the terms: Iron is the chemical term for Fe metal. All iron-alloyed metals are called steel, so we have hardenable steel (with carbon content usually exceeding 0.5% in praxi) and steel with so low a carbon content that it cannot be hardened.

I have always preferred the old use of iron (meaning not hardenable) and steel (hardenable because of its C-content).   


I like your definition of "iron" a lot.

One thing I've gotten very tired of in most discourse on armor metallurgy is people using the term "iron" without any kind of definition because it sounds cool. What complicates the matter is the poor translations of Japanese terminology into English, with tetsu being translated in a very literal sense as "Iron". When we look at the historical usage of the term, it's often a very vague catch-all term for a ferrous metal. If we are talking about Late Muromachi and Momoyama period armor, you'll find a lot of it is truly steel, or laminates of mid-high carbon steel with low-mid carbon on the inside of the plate. 

It also must be mentioned that plates are hardened through cold working. This isn't a true industry secret, but not many seem to know about it. Most armor you see nowadays is just roughed out into shape with a mallet and forced together either by bad riveting or welding. The way it's really done involves thousands and thousands of small hammer blows working it into shape. Ideally, it should fit together on its own before riveting so as not to have uneven tension in parts causing stress on rivets. Needless to say, this is a lot of work... One other culture that uses this method were the Tibetan Armorers who also cold hardened their plates. In essence, you harden it as you shape it.

Generally speaking, there isn't just one standard type of iron/steel with Japanese armor. There is a huge, huge variety of different things that have been used over time. It depends on region, group/school, era, etc. And even within those classifications there is considerable variation.

That's why we need to get very specific. People want easy answers where there are none in essence.

Another thing that is extremely important to factor is plate thickness.

Focusing on Kofun era helmets, the main plate of the Shokaku is generally 1.5-2mm thick with the rest varying depending on the part. The bands for example tend to be thicker with the plates making up the body which appear to be somewhere around 1-1.2mm.

Always, always avoid wide sweeping statements with Japanese armor, or looking for easy answers.

Always pick a specific example, and copy it to the best of your abilities. When people try and pick something "general" it always leads to problems.

  • Like 3
Posted

Corrections accepted gentlemen! Yes, it is more complicated than it at first seems, and I have to keep reminding myself. So far, my only experience with iron/steel forging has been hot, and in my limited experience wrought iron has been a bit harder to work with, because it needs more heat. That's a good reminder though that wrought cold forges nicely! It's not always practical to fire up the forge, so I really should spend some time cold forging the wrought pieces I have that are close to ready. I also like Jean's definition, and I will endeavour to use it in the future. 

  • Love 1
Posted

At the end of the day, all of us are experimenting and trying to piece together what it was these guys were doing.

One of my big goals is to be the first armorer to revive the laminated sheet technology. I got ahold of Sakakibara Kozan's writings on the topic, as well as some metallurgical analyses of some examples.

Fingers crossed I can bring it back into the modern era. I don't think anyone has done it since Late Edo... And that's assuming Kozan's writings were not just speculation but actual implementation.

I advise everyone to take the metallurgical aspects seriously, but also to experiment. I think it's the least understood and appreciated part of the art!

  • Like 1
Posted
13 hours ago, Arthur G said:

you'll find a lot of it is truly steel, or laminates of mid-high carbon steel with low-mid carbon on the inside of the plate. 

Do you know what is the reason for the laminates? Is it like the making of knives: have the minimum of strong steel required to be efficient and back that up with low-C steel or iron?

 

I personally find that many analyses lack in one way or another. The whole "well forged iron" that I keep mentioning about tsuba is one of them. But even some papers with more advanced methods (neutron diffraction) appear to give very clear cut interpretation of the data, while I would deem them more murky. In the image you uploaded, the pure iron is deemed to have been forged at around 500℃, but I don't understand how they came to that conclusion.

Posted

Arthur,

in the 50's, traditional ploughshares were made as laminated construction in Germany, so it is not an unusual technique. The idea behind it was that the 'soft' iron layer would wear away faster than the hard steel layer, resulting in a 'self-sharpening' edge in use. 

In armour, there is a different idea behind that technique: combining hardness and toughness. But it has to be considered that in very thin workpieces the carbon migration is a big factor, so in case there are many heating cycles at welding-temperature, in the end you may not be able to tell the iron from the steel layers.

As far as I know, the general defensive principle in Japanese armour is dominantly to take up energy from a sword strike, while European armour is made on the 'shell' principle (like an insect's body). This lead to very heavy armour in later periods in Europe - and heavy, almost blunt weapons.

I think it is correct that the toughness of of the laminated sheets of the Japanese KACHU is/was more important than the hardness (which always implies the risk of brittleness). A thin laminated sheet metal may indeed be an improvement, and it is an old forging technique in many cultures (not only in Japan) to combine steel and iron, as we see it still today in cutting tools as shown below. 

 

Parmesan-Hobel 4146.jpg

IMG_6875.JPG

Posted
4 hours ago, ROKUJURO said:

As far as I know, the general defensive principle in Japanese armour is dominantly to take up energy from a sword strike, while European armour is made on the 'shell' principle (like an insect's body). This lead to very heavy armour in later periods in Europe - and heavy, almost blunt weapons.

I think this is a misconception, that European weapons were heavy and blunt (if we are talking about swords). Indeed, I think in terms of weight, they are similar to our beloved Japanese weapons (in 1~2kg range, unless we get into zweihanders). It can certainly be argued that many swords used along with plate armour were not as hard as the edge of tachi or uchigatana, and the smiths may have preferred producing blades that were closer to springs. Now if we talk about maces and warhammers, they certainly aimed at a lot of blunt damage, but they were not that heavy, rather balanced towards the head.

 

About Japanese armour, there is a video or the Tokyo National Museum where they do try an armour, but alas, they do not seem used to wearing it. It has now been deleted, but a branch of the sosuishi ryu did upload a video of paired kata in tosei gusoku: the interesting part to me was that even when kicking a fully armored opponent to a wooden floor, there was almost NO noise, compared to the clink clank from European plate armour. It is also my understanding that Japanese armour never uses purely flat plates (especially for the kote, suneate, and kabuto) where the strength of the cold-worked metal is further enhanced by the reinforced structure of the metal (I think "u" cross-section for arms and legs and "L" for the helmet?).

Posted

Arnaud,

when I wrote ''This lead to very heavy armour in later periods in Europe - and heavy, almost blunt weapons' I was referring to the late medieval era and afterwards in Europe when warriors wore plate armour. 

While Viking swords (end of their reign was roughly mid 11th century) were not pointed but sharp and weighed only about 700 - 800 g (and indeed very close to KATANA blades), the swords of these mentioned later medieval times (15th through 17th centuries) were nearly about twice as heavy. Fighting an opponent in plate armour did not require a sharp sword but a heavy one.

In Europe, the medieval era lasted for about 1.000 years, and in this long period of time, many develoments and changes took place!  

Posted

Jean, I understand that swords evolved tremendously in Europe in particular, but I still think my point stands. This is getting quite off topic, but here goes.

 

A two-handed sword of the 15th century: 1560g:

https://www.metmuseu...lection/search/27966

A one-handed sword, the rapier: 1500g. Supposedly a very nimble weapon:

https://www.metmuseu...lection/search/22367

 

I believe the whole issue is balance. The myth of heavy blunt medieval swords is said to have come from the 19th century, from people who were not used to such swords. From personal experience, I have had people carry my shinken, and everyone who doesn't do iai thinks it's like a crowbar, while people who do iai think it's like a feather (it's about 930g for 79cm).

 

If you look at sources about fighting in Europe, half-swording and wrestling is used when fighting an opponent in armour. There is no need to bludgeon with a sword: you use the point to get in the gaps (visor, armpits, etc.: https://www.youtube..../watch?v=49TBEhDtSc4) (although it seems you can bludgeon by holding the sword by the blade and hit with the crossguard or pommel, but then again, armored gloves).

  • 2 weeks later...
Posted
On 9/1/2023 at 8:11 PM, Arthur G said:

Which specific type of Kofun helmet?

If you can show the exact one you're copying it might help.

 

Sorry for my late response. Had a lot of work the last two weeks. I am going for this:

n64qbgx3cbn51.thumb.webp.a0e8ce4602fc140c37a318e457c7a540.webp

 

Helmet from the MET. I thought this may be a good place to start, because of the small parts and I think bronze is easier to work with. I haven't found out how to make the round top part, my guess would be that it is either casted or punched. I've got a DC1 Steel now, that was easy to get and cheap, so if I make mistakes (which I surely will) it isnt a huge financial loss. Thank you for the papers, I'll take a look at them when I am home.

 

On 9/4/2023 at 9:33 PM, Arthur G said:

That's why we need to get very specific. People want easy answers where there are none in essence.

Another thing that is extremely important to factor is plate thickness.

Focusing on Kofun era helmets, the main plate of the Shokaku is generally 1.5-2mm thick with the rest varying depending on the part. The bands for example tend to be thicker with the plates making up the body which appear to be somewhere around 1-1.2mm.

Always, always avoid wide sweeping statements with Japanese armor, or looking for easy answers.

Always pick a specific example, and copy it to the best of your abilities. When people try and pick something "general" it always leads to problems.

 

Do you have any resources you could reccomend for someone starting to get into Japanese armour making? I've got the book by trevor absolon and one by suenaga masao which is in prewar Japanese, so beyond my reading abilities at the moment, but neither of them go really into details of how to start. I made a cardboard mockup of some kozane and tried lacing them together

WhatsAppImage2023-09-16at14_41_04.thumb.jpeg.e1d3ce8cc4315fb5d9ceadeccbca5df0.jpeg

 

which I then want to repeat in nerigawa/tetsuzane when I have found the best dimensions and worked out, how many of which type of sane I need. 

Posted

Florian,

perhaps DC01 is not the best choice (....Das Material eignet sich für mittlere Verformungen und wird im Allgemeinen für Kant- und einfache Ziehoperationen eingesetzt....). Bronze has to be 'hand'-made to your special requirements. In any case, it has to be cast first, and a bronze alloy that can be shaped by hammering needs a low tin content which is not readily available.  

The upper round parts of the helmet can be formed easily in a wooden mold. I could send you photos of such molds in case you are interested (send me a PM). 

Another part of the work might be the production of small rivets and the special tools that are necessary for their application on the helmet. You need a small riveting hammer, too!

Tell me if you need help, I am not so far away from Heidelberg.

 

This thread is quite old. Please consider starting a new thread rather than reviving this one, unless your post is really relevant and adds to the topic..

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...