Yokoya School Piece Under Investigation.

[Ford Hallam]

This is a kozuka that is housed in the V&A repository in London. Catalogue number: M.1259-1931

 

In March of this year it was part of a fairly large materials analysis survey I carried out as part of my on-going research into the history of these curious Japanese alloys.

 

This is in fact the first documented and positively identified example of Kuro-shibuichi, black-shibuichi. You saw it here first.

 

There are a few recipes given in early 20th century texts for making this alloy. These compositions are what subsequently appear in modern Japanese publications.

The problem I've had is that I've not yet been able to find any Edo period examples that match these particular compositions, which are given as ratios of shakudo and shibuichi.

 

This piece, with a mei purporting to be that of Yokoya Sōmin, has a composition that very closely matches a composition given by the Imperial artist Unno Bisei II ( 1864-1919. and from Mito)

He advises shakudo in 10 parts and silver in 3 to 4 parts. There's obviously room for some variation here as the shakudo alloy's gold content is not specified but a narrow range of possible compositions can be estimated quite easily based on typical shakudo alloys of the period.

 

 

and the mei. Apologies for the poor images, it was a long day.

 

Anyway, this is just a little something I was working on this morning and thought might be of interest to board members. Any thoughts on the mei would be welcome.

 

 

kind regards to all

 

Ford

[Tanto54]

Dear Ford,

 

Sounds like exciting research - I'm so pleased that you are doing it.  FWIW (and you know far better than I) but I don't believe that this is Somin's signature or work.

[Curran]

Hi George,

    Yes, I was wondering which way he was going with this. The implications of a large pool of museum examples having material analysis forming a comparative database are interesting, if it is finally feasible.

[Ford Hallam]

Cheers George, yes , the mei is somewhat dodgy but I thought it'd be a fun exercise for some :-)  The work on the front is more reminiscent of Joi and is actually rather good in hand.

 

Hi Curran, just working with a relatively limited amount of data I've thus far amassed it's starting to yield a remarkable amount of usable information. It's early days yet but I think this analytical approach to the subject may well eventually rewrite much of our 'accepted wisdom'.  Certainly the probability of there being school or even studio specific alloy compositions already seems to be hinted at. And with a broad enough survey issues of gimei may eventually resolve themselves where analyses reveal the pretenders.

[Steve Waszak]

Terrific stuff, Ford. 

[Curran]

Hi Ford- I may be twenty years out of the science lab and therefore a fossil, but I would be interested in the technology. 20+ years ago it was the size of a Volkswagon Beetle and not confidently reliable.

With computer advances, I felt it was evident 15 years ago that we would eventually have the technology be small enough and not too invasive.

If it is finally practical, I hope you do groundbreaking work with it.

 

I'd gladly volunteer, just to look and learn over your shoulder. Some day I hope you can get access to collections like the Boston Museum with it wide range of superior kinko tsuba and other pieces.

From observation, I am inclined to believe there were school and studio specific alloy compositions.

[John A Stuart]

It really seems logical to suspect that each school would have proprietary formulae for alloys, they did for everything else. John

[Ford Hallam]

Curran, John

 

yes, the technology has advanced rapidly in the past 15 or so years. The device I've been using looks a bit like a bar-code scanner you'd see in a supermarket. It's completely non-destructive, penetrates though surface patina and corrosion and delivers results up to 3 decimal points in under 30 seconds. The only drawback at present is the cost of buying the kit, I've been supported on a few surveys thus far by the agents here in the UK.

 

I'll be discussing this survey idea with the Ashmolean, in Oxford, in the new year and I've had discussions with the MFA previously.

 

What the basic analyses have already revealed is that the range of alloys is far greater than previously documented or imagined.

 

The real work, though, is trying to understand what all the numbers actually mean. What does the inevitable trace of lead in copper tell us, the arsenic that crops up in certain alloys but not others, and tiny traces of gold in silver and shibuichi? Which bits are deliberate, which where unknown to the makers, how do alloys change over time and what of remelting alloys? There are many such issues that must all be factored in to the interpretation of the data. 

 

And then these analyses must be anchored somehow in the historical record. By which I mean we need to try and fit individual analyses results in to a time-frame. This context, using dated pieces and the working lives of the artists who made authenticated pieces, may then help to establish some sort of chronology of alloys and metals in the Japanese metalworking tradition.

 

I hope to be publishing the results of my investigations very soon

[John A Stuart]

Yes, from analysis results I have seen on bronzes in the Levant you can track origin sources of copper through trace metals. Lead being one of the common ones. It will get more complicated when you have to factor use of re-purposed or recycled alloys. Looking forward to seeing the results. john

[nagamaki - Franco]

Hi Ford,

 

Are patterns of consistency beginning to emerge to the point where school and/or artist can begin to be identified? Or is that still way off in the distance? Thank you.

[Ford Hallam]

Hi Franco

 

I found one group of a very particular, perhaps unique, brass alloy used by both Mitsuoki Otsuki and his son. This in itself is very suggestive but would only become more reliable with more data.

 

Similarly the 'so called' sentoku used by Mitsuhiro, he of the 1000 monkeys etc. has been shown to be essentially the same alloy (again pretty distinctive/unique) in a number of pieces by him/them I and II.

 

Patterns are emerging in the shibuichi group that may allow for a degree of dating to be established.

 

But beyond this we really need a much broader data set. For example there may be consistent variations in varieties of shakudo from different centres of production but without lots of analyses of work from Edo, Kyoto and perhaps Osaka I don't have enough to see patterns as yet. I'm fairly confidant these patterns will emerge as we build up the data set because already I'm seeing a much greater degree of variation and distinction than we previously imagined. It may be as varied as paint colour mixtures used by different painters in the Renaissance.

[b.hennick]

As a retired science teacher I appreciate this approach that you are taking. If the equipment is not invasive and portable perhaps it could be used on papered pieces at a sword show or even DTI. 

[Curran]

I found one group of a very particular, perhaps unique, brass alloy used by both Mitsuoki Otsuki and his son. This in itself is very suggestive but would only become more reliable with more data.

 

 

In stating earlier my observation and belief that certain schools used distinct alloy compositions, I thought of Otsuki, Kozenji, and a certain type of Hamano metal from the late 1700s-early 1800s.

Reading your confirm of Otsuki makes me want to send you Kozenji works.

 

Just off the top of my head, designing a test of sahari used in various signed, unsigned, and only signed "Hazama" works would be of great interest to me to try and seperate the wheat from the chaff in the various debates there about the Kunitomo <-> Hazama schools.The arrival of this technology certainly could revise a lot of the..."Accepted Wisdom" as you called it.

    Really this could be a significant rewrite. It is sure to see opposition. For those of us who fully welcome it, may it scientifically live up to our hopes.

[Ford Hallam]

Hi Barry, having a device on hand at a shinsa is something we have already discussed here in Europe. I'm working on it. :-)

 

Curran, sahari has been investigated. I have the metallurgy pretty well covered now. In fact sahari has a much older history than the Hazama and Kunitomo groups but it appears in the historical record somewhat differently. It's a bit complicated to explain in a forum post (it's  a chapter in my book) but the alloy itself goes back more than 2000 years and was in this instance a Korean invention. The trick is in how it was heat treated.

 

With respect to analysis data being used to authenticate works, we'd need to sit down with a good spread of pieces to establish a useful data set. A 50 sample survey could be done, at an event almost anywhere were the pieces made available, in an afternoon.

[Curran]

Hi Ford,

 

On Kunitomo <-> Hazama, my focus is narrower than that. I'm quite aware of the Korean pottery link, though didn't know it went so far back. I thought only 1000 years. My wife doesn't own any examples in her Korean pottery collection. This is not for lack of trying. I've long wondered how the invasion of Korea and the large scale bringback of Korean potters might have influenced Japanese sahari.

 

With the Hazama and Kunitomo having moved around so much in the 1500s and 1600s, I hope to establish a few identifiers to the pre 1700s before the known of the Kunitomo (Teiei, etc) setting up permanent shop.

Minutia such as the differences in the size and frequency [between Kunitomo and Hazama] of bubbling in sahari probably have some alloy distinctions. The old texts talk about the differences in sahari color being due to differences in the ratios of copper, tin, zinc, lead, silver etc.. I've accidentally scratched sahari on a Kunitomo before and can testify to the visible presence of significant copper, though it heals different than shibuichi.

        We'll save it for another time. You have bigger, much more interesting datasets to establish.

 

It is just fascinating work for those of us with a heavy science background who sometimes get frustrated with the Accepted Wisdom approach and its inability to advance from current knowledge level quagmires.

It won't change the world, but will keep us enthralled seeking better understanding within our little corner of it.. Thank you again for sharing.

 

Curran