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Posted

Hello to everybody.

 
I have spent some time trying to figure out the age of this Heiajo tsuba.
 
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Dimensions: 79.0 mm x 75.1 mm, 4.5 mm thickness at mimi, weight 146.0 g.
 
The seller dated it to the Edo period but I would like to be more specific if possible. Attribution to the Edo period seems to be the default when the piece is obviously old but difficult to place, I mean, the general rule seems to be "When in doubt, Edo Period".
 
I have found three similar tsuba on the Otani book "Tanoshi Shinshu Zogan Tsuba" dated between Muromachi and Azuchi-Momyama ages.
 
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A rough translation of the accompanying text says (more or less):
 
"The peony leaves in the lower part of the ground in combination with the thick trunk, the fine point inlay and the bell flowers on the mimi gives a feeling of the era (Muromachi/Momoyana). Both brass and the base iron are strong and of old color."
 
It seems that the design, the presence of the dot inaly (sen zogan), the design of peonies and their trunk, the color of iron and brass are considered by Otani the essential kantei points.
From what I can see from the pictures the way in wich the peonies, their trunk and the brass dots of the Otani tsuba are made in the same way of my tsuba. There are small differences, also among the Otani tsuba, on how the peonies leaves are rendered but the similarity is still strong.
Comparing how the flowers and the leaves on the mimi (Chinese bellflower) are actually represented with similar designs from Otani my  feeling is for Early Edo.   
 
I have found also other similar tsuba on the net but their age attribution seems to be more uncertain.
 
For the iron I find it rather difficult to make comparison of color and texture between my tsuba and pictures considering how subtle is the effect of the lights set up on the final color in the picture not mentioning eventual "enhancements" to the picture itself. Thus I limited the comparison to tsuba I own and coming from trusted sources. The reference tusba where a Tosho from Early Edo period, an Umetada from Edo period (ex Thierry Bernard) and a Late Muromachi Katchushi (ex Robert Haynes and Elliot Long) among a few others.
The iron patina of my tsuba seems to be like dark chocolate brown in most cases. Under direct sunlight it gets a more bluish hue.
The color and texture of my tsuba are almost the same to those of the Tosho, slightly lighter than the Katchushi while the umetada has has a more reddish hue.    
For the brass color I have less "trusted" specimens but a general rule that seems to be more or less apparent from Otani is that the color is more toward the orange/ocher side (opposed to the shiny, gold like, brass inlay of late Edo tsuba) the older the brass is. This gradual change seems to happen passing through a pale yellow not shining color.
Following this rule and using as a guide the Otani pictures again I would say Early Edo. 
 
Of the two hitsu-ana the short one has the fat round appearance of Edo period, while the long one is so stretched vertically that an attribution is rather difficult for lack of many comparisons (why there is the need for such a stretched ana is still a mystery to me!).
The only hitsu-hana of exactly the same shape and aspect ratio that I was able to find in on a non Heianjo tsuba dated to Azuchi-Momoyama/Early Edo.
Both hitsu-ana, cut through leaves and stalks suggesting that they can be a later addition. The cutting seems also to have caused the loss of part of the intersected inlay.
 
So, all considered I would say Early Edo. Do you agree or do you disagree?
 
I would appreciate some feedback from my fellow NMB members that surely have more experience than me on this kind of analysis.
 
Best Regards
Luca
Posted

Hi Luca,

 

Heianjo guards aren't quite my area of focus, but I would date your tsuba to Azuch--Momoyama, not to Edo.  As Henry notes, the style of hitsu-ana suggests a pre-Edo dating, and I see nothing else in the tsuba that points to an Edo Period time of production rather than pre-Edo.  Even without the reference photos you supply here, the details you observe in the piece suggests (to me) an Azuchi-Momoyama tsuba.  But with those photos to add to the consideration, I am scratching my head trying to understand why an attribution of Edo was given to this guard.

 

Cheers,

 

Steve

Posted

Luca,

 

First off, is the book you're referring to that small one?  Note that the colors in it are kind of "off", so you have to be careful using it as a reference (relative to other pieces in the book you can see the color shift in the brass over time, but when you compare it to a real piece...).  I've written a lot over the years about color stuff, so I'll not do that here again...

 

Typically, pieces that look like this are either revival stuff or typically assigned to early edo or earlier.  (like most heianjo/onin-esque work - or so Torigoye says - which does make sense as there does seem to be this gap in time in extant pieces, but I digress...). 

 

The iron used in these isn't really special, other than the old stuff is kind of "doughy" /seems to corrode pretty easily which is what this looks like (to me at least). - the late stuff is typically done on that fine grained sand iron that everybody had access to at the time (which this doesn't appear to be), so I'd discount this being revival work (and maybe even early edo).

 

The hitsu do indeed look ato-bori, though there's something about the number/type of amputations that make me wonder... If they are indeed ato bori, that would indicate the piece could be old (given that the mania for sticking doodads on your sword really didn't appear to take off until the late muromachi/momoyama periods...)  In any case, the hitsu, especially the goofy large kozuka one, would seem to me to point to pre edo.

 

On the other hand, it seems like the implementation of the inlay (from the missing bits it appears kind of shallow) and maybe the color/lack of buildup on it would discount it being really old (like muromachi period). (sometimes its good to look at pieces that are worn/have a bit of damage so you can see now they were made...)

 

So... I would have called it momoyama period work.

 

Who attributed it to the edo period?  Could be that the seller was just being cautious perhaps?

 

Just my .02 that is probably only worth what you paid for it, but...

Best,

rkg

(Richard George)

EDIT: here's a link to a recent yahoo!Japan auction of a similar piece - don't know how much longer it will remain up, but...

https://page.auctions.yahoo.co.jp/jp/auction/w179141823

Posted

Hary, Steve, Richard.

 

First of all thank you for taking the time to answer to my post.

 

In my analysis I was going for an attribution to the azuchi momoyama but then I said to myself, being a total beginner in the field, that maybe I was too optimistic in my evaluations. According to your considerations maybe I was not too optimistic, and maybe I am starting to learn something...

 

Richard the attribution to Edo came from Aoi Art

 

What buffed me the most is the shape of the hits-ana. The short fat one seems to be a little bit too squared on the nakago-ana side.

Equally puzzling is the slim long one, what kind of sword implement goes through it?

 

Anyway Richard you got me I have got of old of that tsuba too...

 

All the best

Luca

Posted

Luca,

 

There are some extant early kozuka that are not "standard sized"/they can be pretty large.  You can see oversized kozuka hitsu on early kyo sukashi pieces, etc. as well...  On those early "kozuka hitsu" shapes, I don't really know why they sometimes have the little divot you associate with a kogai on the kozuka side, though I've always wondered if maybe they were "flipped" and used when kogai on your uchigatana was all the rage, or maybe they were being mounted with the kogai in for a while, or...  Yeah, the kogai hitsu looks newer - almost shoami- like...

 

Interesting that Aoi attributed it later - the last thing I'd ever say about them is that their descriptions are er, conservative...

 

Best,

rkg

(Richard George)

  • 2 weeks later...
Posted

As luck would have it I spent yesterday in the storage facility of the V&A museum in London with free access to the tosogu collection (over 8000 pieces) and a hand held XRF analyser.

 

One of the areas of my focus this time was a group of 45 early brass inlaid pieces. I'll be processing the results over the next few days but putting this hard data into historical context, specifically the availability of pre-made brass or metallic zinc (to make brass) prior to the 17th century might mean that this group of early tsuba may need to be seriously reevaluated.

Unfortunately far too much has been simply taken as fact when in reality there is little to no evidence to support the various dating claims made for Onin and Heianjo pieces in particular. An early 17th century dating for so called Mon-sukashi or Yoshiro guards as well as Kaga would seem to be plausible though.

I would also have to say that the appearance of a surface patina is not really a reliable indicator of the alloys composition. The surface of an alloy like brass, with it's volatile zinc content, can very easily be altered because the zinc so readily oxidises and can be leached out. Also it should be understood that the slightest alteration in terms of acidity or alkalinity in the basic patination recipes will effect the results, as will the time and actual temperature. Imagine then how many similar variables a 400 year old piece of brass may have been exposed to an how that will have resulted in any number of different patina.

And finally in all likelihood these brass inlays were, in my opinion, brightly polished when first made.

 

  • Like 4
Posted

Ford, however small my knowledge on the field, I do agree with you. 

 

 

 

Imagine then how many similar variables a 400 year old piece of brass may have been exposed to an how that will have resulted in any number of different patina

 

The patina of brass is related to its composition and its history over time, that make a lot of sense to my engineering mind I have to admit.

 

However I had a personal experience on another Heianjo tsuba where a small portion of the inlay was accidentally cleaned by an overzealous me (I can be rather stupid at times, but I do not make the same mistake twice :bang: ) using a rather abrasive pencil eraser. Just after cleaning the brass looked gold like, bright and shiny. However the cleaned region regained its original color in a matter of about 10 weeks to a point that the cleaned part was no longer discernible from the surrounding, untouched inlay. Basically the patina was recreated with time. I do not have the pictures of the tsuba, before the cleaning and after about 10 weeks, with me right now but I will try to post them in the weekend if it is interesting for the discussion.

 

To my statement about the "general rule" that can be guessed from the Otani book I should have added the "feeble" adjective, i.e. "feeble general rule", but I do not wanted to sound too heretic since in the book and on other publications I have seen used the color of the brass used as a kantei point. I have often seen sentences like "strong and of old color", "rich color" and so on. 

 

If the brass was brightly polished in the beginning then the color we enjoy is just the result of the composition and the "history" of it.

 

According to what you say Ford, the general rule should be "Do not trust brass color"  :thumbsup:

 

Regards

Luca

Posted
However the cleaned region regained its original color in a matter of about 10 weeks to a point that the cleaned part was no longer discernible from the surrounding, untouched inlay. Basically the patina was recreated with time.

 

Luca, but there is part of the problem. We don't actually know what the original surface looked like. :-) How old was the patina on your piece, that you cleaned? Could it have been 400 years old?, 50...or 5? How would we be able to tell? And as I wrote earlier I believe that probably the brass was in fact 'gold-like'. I have a number of reasons for think that to be the case but foremost would be the way brass was regarded in China, from where the alloy first seems to have come to Japan.

 

In time a natural patina or tarnish will develop on brass and if a bright finish was preferred then it would have had numerous polishings over time. With each cycle of cleaning and tarnishing the surface alloy is subtly changed as zinc is slectively leached out due to the natural oxidising process that is patination. I hope that explanation helps to better describe why the surface appearance of brass is such an unreliable indicator of composition and age.

 

 

Posted

Hi Luca,

I too have acquire three Heianjo/Toshiro tsuba recently and find then impossible to date accurately.  Around 1600 is about as good as it gets for me as Japanese craftsmen often slavishly copied their masters for generations, if a particular item sold well.  Then, of course, if a particular school gained interest amongst collectors, they were copied.  Over the next few days I will be posting notes and questions about my three tsuba, which I hope will be of interest.

 

Best regards, John

Posted

A hand-held XRF analyzer? Which manufacturer & model? I've been trying to convince my wife (also an engineer) to invest in one, but no luck, so far. Looking forward to seeing your results, Ford!

 

Ken

 

Posted

Ken

 

I've been supported by this company, Niton.

 

The actual instrument is made by a company called ThermoFisher Scientific.

 

I've been using the XL2 and XL3t . They're pretty expensive here, especially with the inbuilt camera for accurate positioning but the company have been very supportive in terms of making the equipment available.

 

Posted

Ford thank you for your comments I have to admit the more of your comments I read the more I am eager to put my hands on your upcoming book about alloys and patinas on tosogu. Any news about the release date?

 

 

 

With each cycle of cleaning and tarnishing the surface alloy is subtly changed as zinc is slectively leached out due to the natural oxidising process that is patination

 

This means that the brass patina is more due to the zinc than the copper? If successive patination and cleaning deplete the surface of the inlay of zinc this means that the percentage of zinc oxide in the patina is higher compared to the percentage in the base alloy? Does this means that the formation of zinc oxide is faster than copper oxide and then the formation of the zinc oxide hinder the formation of the copper oxide? Otherwise if the patina has the same composition of the base alloys then the patina formation and removal will not change the surface composition.

 

Just another question. By using XRF to get the composition of the inlay you are testing the patina on the surface of the inlay or the X-Ray are able to get deeper into the metal and give you the bulk composition?

 

Regards

Luca 

Posted

Hi Luca

 

This means that the brass patina is more due to the zinc than the copper? If successive patination and cleaning deplete the surface of the inlay of zinc this means that the percentage of zinc oxide in the patina is higher compared to the percentage in the base alloy? Does this means that the formation of zinc oxide is faster than copper oxide and then the formation of the zinc oxide hinder the formation of the copper oxide? Otherwise if the patina has the same composition of the base alloys then the patina formation and removal will not change the surface composition.

 

 

The presence of the zinc is what causes the usual red patina of copper to change, but both the copper and zinc oxides are present in the patina. Green copper carbonates, acetates etc. can develop over time, depending on what conditions the metal has been exposed to, and their presence will also alter the patina's colour.  Sometimes a few % of lead is also present which will change the patina quite significantly too.

 

In the Yoshiro tsuba example below we can easily see quite red patches on the brass inlay. What has happened here is that due to some surface corrosion, water, salt water, sweaty acidic hands...who knows, the brass has had its zinc leached out. This happens more to the zinc than the copper because zinc is mre reactive in conditions like this.  If this brass was now repolished and repatinated those red areas will patinate to a different colour due to the fact that in those areas the zinc content is lower now.

 

post-164-0-86206400-1500829205_thumb.jpg

 

Just another question. By using XRF to get the composition of the inlay you are testing the patina on the surface of the inlay or the X-Ray are able to get deeper into the metal and give you the bulk composition?

 

 

The types of patina we tend to see on kinko work is around 5 microns thick. The XRF easily penetrates that surface layer. I also did trials at the very start of my research to examine that possible problem and found no real diference in the results of the same alloys whether patinated or polished clean.

 
 
And the book is in the final stages now. This last batch of brass analysis work was scheduled for last October in the Ashmolean but unfortunately due to health and safety issues I wasn't allowed to do the work as planned. I now have the data I need and have been spending the past few day making sense of it all and filling the gaps in my research.
  • Like 1
Posted

So am I Steve :-) I'll be honest it really turned in to a monster but I've nearly got it all nailed down now.  I've literally just finished, only minutes ago, tabulating, sorting and making sense of over 100 analyses of these early brass inlaid tsuba.

 

  • Like 1
Posted

Book-length projects are like that:  they take on a life of their own, and start to push the author around... :glee:  Congrats on finishing!  Now we all get to benefit!  ;-)

  • Like 1
Posted

Thank you for the explanation Ford. 

I have to deal with iron and steel corrosion in my job and I found the subject fascinating. Even more so, it seems to be, for non ferrous alloy.

 

I can't wait to see the book.

 

Regards

Luca

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