ko-kinko? Cast?

[Marius]

Hello there,

 

I have a tsuba (bought from Grey) which I don't quite know what to make of. It looks like made from yamagane with quite decent patina and remnants of black lacquer (the verdigris you see in the picture has been removed with a damp cloth)

 

It looks cast, and that is probably why the previous owner (Skip) has attributed it to kagami-shi.

 

Dimensions are 72x70mm, thickness in the seppa-dai is 2mm, 3.5mm at the rim.

 

Pictures are attached. Thanks for your thoughts

[John A Stuart]

"It looks like made from yamagane.."

Doesn't that preclude it from being kagamishi altogether? Kagamishi were bronze casters, any other medium was not used. Ko-kinko is a much better attribution with those long hitsuana although the mountain shaped kogaiana brings the age forward a bit I think, unless it has been later modified. John

[Henry Wilson]

I would agree with John and also say it is Ko Kinko. It is possibly Kagamishi but only begin cast Yamagane would make such a call uncertain.

[christianmalterre]

Dear Mariusz,

 

well,-i am sorry,but this one here does not look as an Ko in mine eyes-i can be wrong of course-you may know it better-but....

It´s you the soft-metal guy,not me-but mine feeling says two things here...

1. Not that Good

2. Not that Old

(reminds me rather works i have seen;dating from late Edo)

 

It´s a pitty that there´s no old patination left!(if there ever was!)

Again an object,which lost all it´s charm due missunderstood overcleaning and "collectors enthousiast in preservation"(Sorry to say this!)

 

Christian

[Marius]

Dear Christian,

 

I agree it is not particularly good. But as far as patina is concerned... Well, I don't think those pictures do it justice. The patina is reasonably good and and there are some remnants of what seems black lacquer (could be black shoe polish, too, hahaha) :D But it has definitely not been overcleaned.

 

What worries me, though, is an untouched nakago ana - something rather unusual for a tsuba of this age. I would rather err on the side of caution and agree with you that this might be a later Edo piece. I think Steve knows a very similar tsuba, which has been offered for sale as ko-kinko. I could try to make some better pictures in daylight (the posted ones are Grey's), but I don't know if I would not bore people here to death...

[Ford Hallam]

Gentlemen,

 

I don't wish to add to the discussion regarding this particular piece but feel I just have to say something about what appears to an almost supernatural ability on the part of collectors; ie; you chaps to discern the metallurgical composition of metals based only on their appearance.

 

Please don't take me as being overly harsh and rather consider this a kindly chiding.... :?

 

I will defy anyone to positively classify a soft metal tsuba as being yamagane or copper of varying degrees of purity, any of the many varieties of bronze/brass, and an almost infinite variety of related alloys without solid analytical analysis. Speculating on metal composition based solely on it's present patina is simply guesswork. I must admit, and I think I can reasonably claim some expertise in this area , when I read such confidant commentary about metal composition I do sometimes feel like Alice in Wonderland .

 

What I'd strongly argue for is a far more rigorous basis in terms of evidence when we make our assumptions.

 

My apologies to you, Mariusz. I didn't intend to criticise your observations but I've noted this fuzziness of argument in a number of post and blogs previously. Someone has to say something about this....it might as well be me being the bad cop.

[Henry Wilson]

Hi Ford

 

There is a description in Kagamishi Tsuba by Sasano where he says something like, the metal of this tsuba is a reddish colour which indicates a high amount of copper.

 

Would this kind of guess work (which to me is easily understood) be an assumption too far by Sasano?

 

Cheers

[Ford Hallam]

Hi Henry

 

I think in this case, the one you cite, Sasano is being reasonably accurate. It's an objective fact that a reddish colour in non-ferrous alloys can be due to the copper content. It doesn't really tell us much about the alloy as this is merely a relative observation though. It's possible to develop a post office red on a bronze and that alloy would be considered as having a relatively low copper content in terms of the range of traditional alloys.

 

If you think about it it's obvious that we can't make instinctive guesses about alloy composition based on patina colour. Shakudo is a very high copper content, some being 99% copper and yet the colour is still pretty black. Basically, depending on how the metal is treated, it's possible to pull a more red colour out of almost any copper based alloy. Metal patina colours are not subject to the colour mixing theory of painters either. :D

[Marius]

Dear Ford,

 

thank you so much for this post. You are absolutely right - one needs an electron microprobe or a similar, advanced technology to make an assessment of the composition of an alloy. I guess we had all better describe our tsuba as "made of copper or copper-based alloy".

 

Coming back to that tsuba - it could be made of any kind of alloy, with the exception of brass, perhaps.

[Ford Hallam]

To be honest, Maruisz, it could well be brass. :D there does appear to be a hint of yellow/mustard colour in these images. At least on my monitor.

 

We can rule out shibuichi, shakudo and sahari though :D

[Marius]

Ford,

 

as said before, I agree with your opinion. However, I suppose that even without scientific equipment (without wanting to be absolutely precise), one can make an assessment, well, an approximation in some cases. Some of my tsuba must have been mounted until quite recently, and the metal has been exposed in some parts of the nakago ana. I think that if I can see shiny copper, I can reasonably assume that the tsuba is made of copper? I am talking about the tsuba here (picture attached).

 

Obviously, I a not going to scratch the inside of the nakago ana of my tsuba just to "see" what metal it is made of. Most of my tsuba have the old patina inside all ana...

 

BTW, having had a second (and third) look at the tsuba which began this thread I can accept almost any possibilty - yamagane, bronze, brass...

[Ford Hallam]

Yes, I think it fair to say this tsuba is made of copper. There are quite likely some other trace elements present but one would expect that in pre-industrial processed copper.

[Marius]

Yes, I think it fair to say this tsuba is made of copper. There are quite likely some other trace elements present but one would expect that in pre-industrial processed copper.

 

 

Good, that means that we one be reasonably sure in the case of some tsuba made of copper (I would say suaka). But where is the cut-off for our assessment? It is very tricky indeed. Yamagane will patinate to some very dark colour, I was told, is that true? Patina on suaka will look differently...

 

Here is a picture of yet another tsuba - no nakago ana scratches to confirm that it is copper, but that is what I (hopefully reasonably) assume...

 

When I look at old soft metal tsuba I find it very tricky to asses what it is made of mostly when it has dark patina. Old shinchu does not patinate so easily, I was told, and retains its golden colour, which is said to be especially rich if the shinchu was imported from China.

[Ford Hallam]

Yamagane is, as you know, unrefined copper and contains various trace elements. The mos significant in terms of it's effect on the patina is arsenic. Typically Yamagane alloys contain about 1 ~ 0.5 % As and exhibit a deep chocolate colour wit various overtones depending on the actual composition.

 

Old shibuichi does not patinate so easily, I was told, and retains its golden colour, which is said to be especially rich when the shibuichi was imported from China.

 

I don't know the origin of this notion but I have never seen any Chinese artefacts made of shibuichi nor read any reference to the Chinese having exported it. Joseph Needham, in his extensive writing on Chinese technology certainly never mentions anything like it. Personally I'm not convinced that shibuichi was used before the Early Edo period and it does seem to be uniquely Japanese, unlike shakudo. What can and does often happen with shibuichi that has been handled a lot is that the copper content oxidises and is eventually leached from the surface leaving a silver rich patina of sorts.. You can sometimes see this around raised inlays and where the rest of the body of the ground has then been further "abraded" by handling and reformed a much darker patina then the original colour.

 

On copper, suaka, do, aka-gane are all synonyms for copper but some people use the term suaka to also refer to the terracotta/persimmon fruit colour like that on the second example you've posted.

[Marius]

 

I don't know the origin of this notion but I have never seen any Chinese artefacts made of shibuichi nor read any reference to the Chinese having exported it.

 

Sorry for a stupid mistake I have meant shinchu and NOT shibuichi, of course. I will adjust my previous posts to avoid confusing readers of this thread.

 

Apologies

[John A Stuart]

Ford, Reading your passage on Yamagane, I wonder at what % As with Cu does the metal become best described as bronze rather than impure copper. I know that arsenical bronze predates other types of bronze in mid Eastern weapons because some of the copper ores first used to produce copper were high in arsenic, like malachite, and if the ore is not highly oxidised in smelting to release the arsenic in oxides, very poisonous BTW, the result is arsenical bronze. Actually a more efficacious alloy than pure copper, as it is tougher, harder and better to work harden at even low concentrations of arsenic, 0.5%. It was learning how to manipulate the arsenic % and later adding other metals to form bronze alloys that we have the change from the copper age to the bronze age, which happened at different times in different places, in fact, Japan never had these periods jumping from a neolithic to an iron age people ( as the use of metal, both iron and bronze concurrently, slowly spread over the islands). Using tin was less poisonous which may account for the disfavour arsenical bronze eventually had. John

[Marius]

Ford, John,

 

Interesting discussion, thanks for that As this is highly interesting for me (given my penchant for irogane ko-tsuba) I am delighted to have started the thread :D

[Ford Hallam]

Hi John

 

This from Wikipedia;

Since copper ore is often naturally contaminated with arsenic, the term "arsenical bronze" when used in archaeology is typically only applied to alloys which contain greater than 1% by weight of arsenic, in order to distinguish it from potentially accidental additions of arsenic

 

The modern commercially available alloy called kuromido contains 3% As but is not regarded as a bronze by kinko in Japan as far as I know. I use kuromido to add 0.5% As to my shakudo alloys when I'm recreating Momoyama period shakudo that needs a true soot black patina.

[John A Stuart]

Hi Ford, Oh those wiki guys!! :lol: Kuromido at 3% As not bronze for Kinko artists? Now that is interesting. Thanks, John