Engraving After Casting?

[ROKUJURO]

Thank you, Ian,

I know the story about YAGYU's TSUBA test, which might be seen as a hint that TSUBA have generally not been hardened which makes a lot of sense technically.

What 'bones' (TEKKOTSU) are and how they are formed is another story - I am working on that feature, and I can assure you it is not by abrasion or wear that they show on a TSUBA!

There is a strong contradiction in your description as cast iron is indeed highly carburized (up to more than 4%) in comparison to steel (up to ca. 2%) or iron (up to 0.22%). 

For my understanding of TSUBA production, I am not convinced that casting iron could have been a possibility   

[Marius]

Jean,

 

Here is an excellent ariticle about tekkotsu by Boris Markhasin and Andy Mancabelli.

tekkotsu very good article.pdf

[kissakai]

Thanks for the article especiaaly a possible raised mimi of the Myochin school

Do we have anywhere clear images of tekkotsu as it is an area I've a lot to learn

[ROKUJURO]

Thank you, Marius!

The problem about this very special subject is simply that many authors have little knowledge about metallurgy. In most cases, statements are made based on aesthetical criteria, beliefs and 'logical' observations. Of course we see with our own eyes that the earth stands still and the sun makes her way from East to West in the daytime. But fact ist, it is not true.

It is the same with many features of arms and armour. Which one ist the best steel for knives? - a standard question of many customers.  I am very skeptical about the competence of an author when I read: 

.....The metal is very dense and hard – likely steel.... 

Density and hardness are physical dimensions, and they need data and facts. High carbon steel can be soft if treated correspondingly. The problem is that impressions and assumptions don't help. They have to be supported by evidence, if you want to expand the given knowledge on a subject. In NIHONTO literature, I often have the impression that old remarks from 'renowned experts' are just repeated and cited without ever questioning their content. As I have some experience, knowledge, and the possibilities (but often not enough time and money which slows down the process) to do real research in a few limited fields, I am behind some 'secrets' which are no enigmata but just a lack of general knowledge.  

Would you like to help me? I need a few worthless TSUBA or pieces thereof with pronounced TEKKOTSU for hardness and other testing. This will allow me to support new theories of an old subject, and it will probably yield some surprizing results. Some books may have to be revised, I think!   

[IanB]

Rokujuro,  As someone who has worked with metal in an amateur way all my life, I do have a little empirical knowledge and have machined, and tried to machine, quite a lot of castings. I also know that craftsmen everywhere develop techniques that maximise their productivity. There is a delightful Youtube video of a guy making the beads for soroban that illustrates this perfectly. Basically he has a hand driven spindle which protrudes through an angled plate on which he pops a rough bead and then slides a blade along the plate. It takes seconds to produce the shaped beads what would be quite tedious to make any other way. There is no doubt that there are vast numbers of tsuba made by forging a plate and decorating it by piercing, chiselling and filing, but there are also a large proportion, of which some of the more delicate sukashi tsuba are examples, which would involve considerable labour to make considering the amount of metal that would need removing. Modern tsuba makers resort to piercing saws to produce this kind of tsuba - something they did not have in the past. We know that kettles were cast and decarburised, so why not use the same process to turn out the basic forms for tsuba? They would need additional work to finish them, but at least a large amount of labour would be eliminated. Having said all that, I have no proof whatsoever that this is what was done, other than Yahoo Japan quite often has tsuba for sale with bits broken off. I once owned a sukashi tsuba of drums and lightening which had a section that had snapped off and had the broken edges filed smooth. Had this tsuba been forged iron, it would have bent and could have been easily straightened. I suspect it was incompletely decarburised. What this whole saga needs is as you say a metallurgist to cut up and examine some junk tsuba.

Ian B

[Steves87]

What 'bones' (TEKKOTSU) are and how they are formed is another story - I am working on that feature, and I can assure you it is not by abrasion or wear that they show on a TSUBA!

 

  

I often have the impression that old remarks from 'renowned experts' are just repeated and cited without ever questioning their content. As I have some experience, knowledge, and the possibilities (but often not enough time and money which slows down the process) to do real research in a few limited fields, I am behind some 'secrets' which are no enigmata but just a lack of general knowledge.  

 

  

Had this tsuba been forged iron, it would have bent and could have been easily straightened. I suspect it was incompletely decarburised. What this whole saga needs is as you say a metallurgist to cut up and examine some junk tsuba.

Ian B

Thank you!

[JohnTo]

Hi Guys,

Grev asked for examples of non ferrous Nanban tsuba.  Here is one, together with an almost identical one in iron.  Both have animal/demon masks at the top and bottom (the iron one has them at the sides as well) and have dragons in the side panels.  The brass tsuba has pearls in inome bori (boar’s eye, heart shapes) piercings at the side.  The iron tsuba has some gold nunome and the rim of the brass tsuba may have traces of gilding.

The brass tsuba has copper seki gane in the nagako ana, indicating that it was mounted, and a shakudo plug in one of the ryu hitsu (must have been quite an effort to have shaped that!).

The Compton Collection had a similar brass tsuba (Part I, lot 100) which was described as a Canton tsuba from ca. 1600, with no ryu hitsu.

Reading between the lines from various sources (I don’t have hard evidence) it would appear that this style of Nanban tsuba originated in China (Canton) and was exported to Nagasaki, along with Chinese craftsmen who set up shop there.  From there they migrated into the adjoining Hizen area where the tsuba became more Japanese (e.g. nagako ana lost the square shape of these examples) and possibly kicked started the Hizen style sukashi (100 monkeys, etc).

Best regards, John

(just a guy making observations, asking questions, trying to learn)

[kissakai]

This is from the Birmingham museum

There are around 50 Namban tsuba in my book but only this 'kinko' type.

]Must be rare