A question about iron bones

[Antti]

Greetings again,

 

Now that I have a camera, I wanted to ask you about linear tekkotsu on my Akasaka tsuba. The tsuba was discussed more in detail here:

viewtopic.php?f=2&t=16346

 

There seemed to be agreement that the tsuba was made in the late Edo period, which was also my conclusion when I acquired it.

However, there seems to be one clearly visible, linear, bone on the mimi. The rest of the mimi is perfectly rounded, and this bone was therefore very distinctive.

 

A couple of questions

 

1. Is it common to see tekkotsu like this on a late Edo tsuba?

 

2. Does linear tekkotsu automatically mean it has a layered construction? I know that earlier Akasaka tsuba had layered construction, and the later ones, like this, did not. I attached a picture of inside the sukashi, which, in my eyes, shows no sign of layering. It should be noted that I havent seen many examples of layered construction sukashi, so perhaps I am wrong.

 

3. If it does not have a layered construction, would this be just natural tekkotsu, caused by the rubbing against the apparel of it's wearer? As I noted this long tekkotsu is the only abnormality in an otherwise perfectly rounded mimi, which, I think, would implicate this. Now I do not know how long it takes for this kind of effect to form, but I would expect it to take quite a while. However, again, if this is a late Edo example, the tsuba could not have been worn by several generations.

 

The bone was not easy to photograph, but I gave it my best shot.

[Marius]

Antii,

 

these are not bones, but evidence of folding.

[Antti]

Aha, well that destroys my theory

 

So that is a fold line then? It was difficult to photograph but it feels like a slightly raised edge on the round mimi, as perhaps best seen on the photo on the left. I should note again that this not seen anywhere else on the mimi.

 

Well, this just raises new questions. Folding, as far as I have understood it, is to even out the heterogenous carbon content of the steel. Now if I've understood this correctly, the late Edo steel was often mass produced, more homogenous "factory iron". I would assume, that there would be no need to fold a factory iron plate. So could I draw a conclusion that this tsuba was made from heterogenous steel, as it has been folded?

 

(edit) One more try:

[ROKUJURO]

Antii,

 

a very nice TSUBA!

 

All steels from all pre-industrial manufacture had to be folded and fire-welded to homogenize them. TEKKOTSU can be related to insufficient homogenizing so there remain larger lumps of iron in the steel. Industrial steel means steel made in a blast furnace which to my knowledge was not made in Japan before the end of EDO period. Nevertheless, Japanese smiths had imported NANBAN TETSU at their disposal as early as about 1600, so roughly at the beginning of the EDO period. I don't know if it was easily to be had by any smith at that time, and I don't know if TSUBASHI used it the same way as sword smiths. The latter sometimes signed with the additional remark 'NANBAN TETSU', but I don't remember having seen this on TSUBA.

 

Features on the TSUBA directly related to layering are sometimes encountered as narrow linear TEKKOTSU (as on your TSUBA) or as small cracks or fissures, sometimes both in one place. Although still often repeated, TEKKOTSU does not form from wear.

[Antti]

So I guess the big question is, can the feature, displayed in my pictures, be classified as tekkotsu (as Jean wrote) or perhaps not (as Mariusz wrote).

I'm assuming that the word "tekkotsu" and "iron bone" are exactly one and the same thing. Perhaps I'm wrong. My assumptions are not improving their track record today.

 

Also I'm shocked that tekkotsu does not form from wear. I've seen this claim so often.

[christianmalterre]

you can answer you this last question by yourself!

 

How shall an microcrystalline conglomeration ben formed due "wear"?

 

This nonsense theorie´s about "wear" and "use" and "age" forming an kind of "look"(resulting automatically in the holy tekkotsu of course!-What else?) is rather an physical thing....

One may call it maybe better "abrasive" in fact.

 

(This forum is crowded with treats concerning leyering,Tekkotsu,Yakite ect ect...do browse via "search/keyword"....some of them are helping you...

do buy you books about Historic(pre industrial) Metallurgy if this fascinating field does further interest you!

 

Nice Tsuba!(out of topic)

 

Christian

[ROKUJURO]

.....the big question is, can the feature, displayed in my pictures, be classified as tekkotsu (as Jean wrote) or perhaps not (as Mariusz wrote).....

Antii,

 

TEKKOTSU and traces of folding are closely related. I have observed that TEKKOTSU can be quite irregularly distributed in the steel (showing mostly in the MIMI), while folding seams are more streched-out and often in one level. Both features can be easily confused, but even the finest crack in it will define it safely as a folding seam.

 

Looking at the inside of the NAKAGO-ANA, evidence of layered construction can sometimes be seen quite clearly. This depends to an extent on the way the opening is cut.

[Antti]

Thank you Christian.

 

I do not know much about metallurgy. Despite having two engineering degrees, metallurgy was not a big part of my studies. But I am interested finding out more as I plunge myself deeper into this hobby. If you could suggest a book (in english) for me, that deals with metallurgy in the pre-industrial era, that would be understandable to an educated man with little understanding of metallurgy, that would be great.

 

However, the tekkotsu via wear-(nonsense) theory is not just some old wives' tale which is spread around to the gullible by the ignorant. For example:

http://www.shibuiswords.com/early%20iro ... 0tsuba.htm

...notes "With the mixture of soft and hard steel of the tsuba, as it rubs against the apparel of the samurai, the softer steel wears away and leaves the harder steel behind. Therefore you get bumps, ridges, and ribs of hard steel - tekkotsu."

This combined with some very impressive names below is rather convincing. Now if sites like this mention it, it is no wonder newbies like me think that it is so. It's not like saying that "you can see the Great Wall of China from the moon"- kind of nonsense that would immideately sound like rubbish. Perhaps sites like this should be updated.

 

Jean, would it help if I could get more/better pictures of the feature? I dont see any cracks in the feature, just a bulge.

[christianmalterre]

Dear Antti,

 

yes-me am well aware and did already expect this question to see arising,...

Fact is-for an metallurgue "such" is out of topic-in fact,this sounds rather "very nostalgic" and is certainly out of proof any reliance to the material study and analysis itself.

This is an conglomerate of nostalgy and collectors dream...not but analytical research....sorrowly!(LOL!)

Would be that easy not?....Laugh!

It but sounds good at least....LOL!

Maybe the authoritie´s in art should sit down together with those doing analytical research on the used materials in future?

(before publishing thesis?)

 

Sorry-mine connaissance into English literature heading to this field is rather marginale...

Maybe Jean does have such?

if not then-

(in german language literature i can give you relating-sorrowly but not in english written one...)

PM me-i´ll send you an list of internationally reputed autorities in metallurgical archeology/metallurgy/analytics in steel ect ect..

Generally but?-...me am very certain such got translated....

 

Christian

[ROKUJURO]

Antti,

 

a recommendation to read would be 'Steel Metallurgy for the Non-Metallurgist' by Prof. Paul Verhoeven (2007). It is available also in German language since last year. It is not an easy read as the title suggests, because it covers the subject in full detail and depth, and my personal feeling is that it is best understood when practical experience with steel is given. Otherwise it remains a quite dry and theoretical book.

 

The difference to many other books on the subject of steel is that it uses latest research technology to better explain the facts.

 

Concerning TEKKOTSU, I will send you my own research results and interpretation via PM.

[Antti]

Thank you so much Jean. I am looking forward to see your research.

 

The Verhoeven book you mentioned was available online as PDF and I already acquired it. I hate reading from computer screen so I'll try to print it somewhere.

 

Other interesting book I saw:

http://www.amazon.co.uk/Ancient-Metals- ... 0982933827

 

At first glance at least, seems to be an academically accomplished author. Publication date 2013, so not that dated either.

[Ken-Hawaii]

Antti, I also downloaded the free Verhoeven eBook, & am actually quite impressed. I've worked in the engineering field for over 45 years, including metallurgy, & this book is useful as a reference for anyone, no matter how well-versed.

 

BTW, I had many of the same questions on tekkotsu as you asked.

 

Ken

[christianmalterre]

an rather cheaper task,before entering into these thematics...

giving you an rough idea at least for starting...

are Prof Coutinho´s essayes...these are around 20 i do have here i think(sorrowly but not in PDF like this one here)

(it but does give you an idea at least-so i hope?)

Christian

[Marius]

The Verhoeven book you mentioned was available online as PDF and I already acquired it.

 

Antti,

 

Would you be so kind and post the link? Thank you

[christianmalterre]

Mariusz,

 

here´s the link for the Scott pdf: http://www.getty.edu/conservation/publi ... graphy.pdf

 

Chris

[John A Stuart]

Be careful downloading Verhoeven's book. There are many links and they pretty well all install adware and spyware that you have to clean later, especially if they ask you to install a reader. John

[christianmalterre]

and again one other: http://www.feine-klingen.de/PDFs/verhoeven.pdf

 

Christian

[ROKUJURO]

Christian,

 

this is basically the book I mentioned, but obviously for free.

[Marius]

Thanks for the links, getlemen

 

Both books are now in my digital library. Pretty technical, but interesting.

[Antti]

I must say that I am glad I asked about this in the first place. Many of my misconceptions were corrected, many interesting sources were shared! Thanks guys!