Dear all, I'm going to make a question that might sound stupid but... do we know what kind of steel is generally used for Japanese armours?
Let me detail. We know that swords generally have a two piece construction where the higher carbon percentage steel makes the Ha, while the lower one makes the "jacket". I would like to know if there is such a knowledge also about armours.
I've got an Hanpo as birthday gift and I would like to restore it. Don't get me wrong, I will go the less amateurish approach as possible.. I have a little experience in the Japanese metalwork tradition, and urushi lacquer.
The hanpo lacquer is ruined; it will be stripped away and re-laquered with authentic urushi. The main problem is, some steel parts was destroyed by rust; being the hanpo simmetrical on it's vertical axis is easier to figure out the dimensions and shapes of the missing parts but I would like to have also a very similar material.
Compared to European armour, a very limited amount of Japanese armour has been examined metallurgically. Documentary sources, such as the text of Sakikabara Kōzan published in 1800, suggest that, particularly with the introduction of firearms in the 16th-century, Japanese armourers went to considerable lengths to increase the protection offered by their armour.
Could metallographic examination of some stray plates donated for scientific analysis, tell us more about the metallurgical quality and effectiveness of Japanese armour?
Results of analysis
This section of armour is of composite construction, comprising an outer face of steel (shown as the dark-etching phase in the micrograph above) and an inner lining of pure iron (the bright phase, ferrite). The steel is distinctly harder and tougher which would help prevent the penetration of projectiles, whilst the softer iron behind is ideal for absorbing the energy of the impact.
The content of slag inclusions is exceedingly low compared with other traditionally produced ironwork and the ferrous plate is protected from corrosion by numerous coats of lacquer.
This armour has clearly been constructed from two different carefully chosen and skilfully worked materials, such that even with a thickness of about 1mm the armour would provide the best possible level of protection for the wearer.
A piece of cheaper armour, examined at the same time was constructed entirely of soft iron containing many slag inclusions so the quality of armour may be very variable.
The results of this recent research were first made public in a series of talks that accompanied the Royal Armouries Shogun exhibition in 2005. A broader research project looking at the metallurgy of Japanese armour is now planned.
Lorenzo, steel and iron laminated panels are described in the 1800s book by Kozan Sakakibara
''The manufacture of armour and helmets in sixteenth century Japan'' or ''Chukokatchu seisakuben'' Translated by T. Wakameda ; Rev. by A. J. Koop and Hogitaro Indada, 1912 ; Rev. and edited by H. Russell Robinson, 1962. Publisher London : Holland Press, 1963.
Pages 23-27 discuss the different methods and types of iron and steel to be used in samurai armor and both arrow and bullet proofing are mentioned. The lamination and folding of iron and steel plates was know and manipulated in order to produce armor that could repel penetration of both arrows and bullets.
The only thing that is not know on existing armors...which ones were made with steel plate and which ones were not.
During the 16th-century improvements in firearms and gunpowder led to the wearing of fewer, but thicker pieces of armour. In recent years it was realised that some of the surviving breastplates had been made by combining two thinner plates. X-radiography was undertaken to identify maker’s stamp marks on the rear plates or those that are obscured by paint or corrosion on the front.
Results of analysis
X-radiography very successfully allowed many maker’s marks to be identified so that the date and provenance of the breastplates could be determined. However, the X-radiographs also revealed an entirely unexpected feature. Some of the “duplex” armour contained three breastplates. Others had further scrap iron or even armour, such as a tasset from a pikeman’s leg armour, sandwiched between the inner and outer plates.
In an additional twist it appeared that some duplex armour was not simply cobbled together old armour, but had been newly made that way. Was this to provide more effective protection? A clue to the possible benefits of such armour may be found in 19th-century research into the protection of iron-clad ships. Penetration by the projectile is achieved through the propagation and growth of a crack in the metal. Where two layers are used the interface between the two acts as a barrier to the crack and thereby prevents failure.
Since publication in the Arms and Armour Journal, many more examples of duplex armours have come to light worldwide. It is hoped that recent collaboration with the Technical University of Delft into the impact resistance of armour will be expanded to test the relative merits of single and double layers of armour.
LOrenzo, Eric, As you might have guessed, I was involved in these investigations - in fact I supplied the bits of Japanese armour to cut up. What surprised me was that a piece from what I am sure was a Momoyama dou turned out to be just plain ferrite, but of good quality with little slag. The composite plate having the steel face was from the remains of a very badly made shikoro. The guy who had made it had hammered it out very roughly and relied on the lacquer to cover the defects. Still it was nice to see that Sakakibara Kozan was right. The civil war breasts were a real shock at the time. As you might imagine we have hundreds of the darned things - they weight a ton and are about as elegant as paving stones. As the text says, they were being X-rayed to ID markings when one was revealed with a bit of pike-man's tasset in it complete with rivet holes. The more we looked the more we found. Some were doublets some triplets. We also have hundred of breasts and backs capture from a French ship at the Isle de Re. What was nice to see on these was that they had been re-furbished from a previous action. Quite a few had tiny diamond shaped holes in them, from pikes, that had been hammered out from the back. The star item though was one that had been hit by a ball making a hole about 3" across. This had been hammered flat and a plate hammer-welded in. When polished you couldn't see anything from the outside, but the patch was only about 1/3rd the thickness of the rest. The poor devil who drew this from stores was getting a poor deal.
Thank you for the answer Dave! Wow, wouldn't have guessed that the thickness is less than 1mm... but then again, I decided to join this forum because this is where the experts on *real* Japanese armour dwell. Plus, I'm not planning to make a suit that I can wear for fighting practice or anything, so it's going to be fine.
Mild steel is good, as it is way cheaper than stainless steel. That being said, how much of a problem will I have with rust after covering the boards of scales in leather and lacquering them? Does it depend on the kind of lacquer that is used, or just on the amount and how well everything is covered?
Edit: Oh, and should the kanagu mawari be of the same thickness as the scales? I'm guessing they should be a little stronger, is that right?
Post by Dave Thatcher on Feb 17, 2015 14:56:22 GMT
The Japanese used very thin iron. The surface is coated with a series of grounds made from urushi mixed with sawdust, clay and flour. Only the final outer layers of urushi encapsulated the plate making it water resistant. Leather would have been skived down to be paper thin, then glued to the urushi surface.
Thanks Dave! But I have to admit I am a little confused. Are you talking about the kanagu mawari right now (with the leather being egawa?), or is this approach the same for boards of hon iyozane?
If the latter was the case, I would have trouble matching your answer to what is said in Anthony Bryant's online manual about hon iyozane scales:
Iyo zane are first tied together into boards of appropriate length by shita garami along their bottom half. They are then given a coating of lacquer, and the entire board is pasted over with a sheet of thin leather. For this purpose, dogskin has always been the prefered medium, as it is quite thin and supple. (Please don't send me hate letters: I like dogs. I'm just telling you the way it's officially done.) The holes for the kedate and nawame garami are next poked into the leather. This whole is then lacquered over, making the board a solid whole which can now be laced to other boards so constructed.
Maybe I should have mentioned that I am planning to make a sanmai haramaki nuinobe do, as the first step to a full armour. And maybe it would be a good idea to start my own thread for the questions that arise during this project...
Well, you know, I hadn't understood Anthony's instructions as "rules", but more like him saying "usually [or typical] iyozane boards were done this way". If that is not the case, then I am even more grateful that you take the time to answer my questions so that I have another reference to rely on. My intention is to use methods that are not exceptions from the rule common practice as much as this is possible for me within my boundaries, which include living in an apartment without a dedicated workshop... so obviously, there will be compromises, some of which will be likely obvious for the trained eye. To avoid this where I can, I seek knowledge here, and I hope that, as naive as some of my questions might be, the answer may lead to "I never thought about this"-moments even for long time members.
Please tell me Dave (or anyone who's willing to), is it not possible to point out a method of construction that was most common for hon iyozane? Or am I misinterpreting your answer here?
David, What Dave is saying is that all manner of variations exist in how armours were assembled. However, the technique outlined by Mr. Bryant is the usual method of assembling iyozane. He did however miss out a vital component. The primary reason for introducing iyozane was to save weight by eliminating the 50% overlap that was used for hon kozane. Iyozane only have a very small overlap. Because of this they need to be sewn onto a strip of leather - the kawashiki which is sewn behind the row of scales using holes 3 and 4 from the bottom. It is my understanding that the leather thongs used for the sewing were of dog skin. So you will need to cut out the scales from your sheet metal and then give then a very slight doming - most of the scales I have seen are not exactly flat. They also differ from kozane in that instead of having one column of 7 holes and one of 6, they have two columns of 6 holes. After being lacquered and laced, they were wrapped in very thin leather so that the join is at the back about level with the 2nd hole from the top. Although leather is traditional, there is no reason why something like hemp cloth or even strong paper should not be used for the plates that are not going to bend- when it is lacquered you will not see the weave. The whole strip is then lacquered and treated as if it were a solid plate. I do not know what was used to glue the leather to the scales but it was probably lacquer. Ian B
Post by Dave Thatcher on Feb 18, 2015 10:21:25 GMT
Hon, made from real individual scales, leather, paper or tetsu. You also encounter fake scales sculpted on ita-mono. Most scales have ground layers between the surface and urushi, common to this is nuinobe do. Decorative leather was expensive, the clan that utilised this the most would have been the Hosokawa. They wore maru and ni mai duo covered in buffalo leather. I've just inspected two hosokawa gusoku that I have here. Both are of iyozane. One has ground, the other I'm not sure about at the chipping has exposed the tetsu. The second would endorse Anthony's account for sure.
Ian, what you say about the kawashiki is most important for my planning, as I totally forgot that Mr Bryant did indeed mention leather alongside metal to make shiki. He seemed to favor metal, although I suspect that was to increase the structural benefit for SCA-related reasons. Leather was much more common then, wasn't it? Also, I will most likely follow your recommendation to slightly dome the plates, even without a workshop this shouldn't be a problem, considering the thickness of 0.7mm. Columns of 6 holes - that's just a typo, isn't it? And finally, your statement about using hemp cloth or even paper is a huge help, because it means that if I can't find (or afford) thin enough leather, I have two legit alternatives
Dave, I really appreciate you checking on those hosokawa gusoku for me!
In conclusion, I will use this approach: after slightly doming the individual scales, give each one a first layer of lacquer. Perform shita garami, including a kawashiki between hole 3 and 4, on the "inside" of the board. Cover the whole thing in very thin leather/hemp cloth/paper, poke the odoshi holes, then apply several layers of lacquer. If anything about this sounds fishy, please let me know.
Thank you Eric! Can you tell me the measurements of the iyozane in this dou and how many rows are in the tateage and the nakagawa? And how much overlap is there?
Edit: sorry, after clicking the link (which I couldn't do at work), I could see for myself that there are 5 rows in the nakagawa and 3 in the tateage. So, only the questions about measurements and overlap remain.