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Is This Shakudo?


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#1 johnnyi

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Posted 13 September 2017 - 05:12 PM

Although it was offered as "Muromachi Shakudo" I am wondering, as the patina seems very thin? Is there a way to tell shakudo based on the way the patina wears off?   (also, if you think  this is a newer  tsuba please feel free to comment, I just want to know what it is)     Thanks,  John I

 

 

p.s. is there a way to clean dirt off a shakudo tsuba without ruining the patina?

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#2 christianmalterre

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Posted 13 September 2017 - 06:10 PM

i do not think this is Shakudo, to be honest...

 

several times already i had "worn" Shakudo pieces in mine own possession- and each time the base material had a very silverish going to greenish/" blue" colouration....( on places there was a abrasive, a worn, or a damage of surface)

 

the worn area on your´s Tsuba here do look like copper colouration....

 

i would be very cautios eitherway- ( with this Tsuba)-definitely  not mine thing at all!....... ;-)

 

Christian


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#3 Curran

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Posted 13 September 2017 - 06:49 PM

I disagree with Christian.

It is shakudo, though hard to tell if it is ko-kinko or an edo version. It is an interesting shape, so I lean towards Edo.

 

This is one where the proper restorer can do a beautiful job, but it might or might not financially make sense.

In its current condition, probably there is not much you should do.


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Michin nom Curran


#4 johnnyi

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Posted 13 September 2017 - 07:18 PM

Thank you both for your insights. I just looked at it again under the sunshine and there is no hint of either silver or blue; just the reddish copper shining through the seppa dai.  My sources for edo things are limited to the internet, but I can't yet find examples of this motif or style. 

 

 

JohnI



#5 rkg

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Posted 13 September 2017 - 07:18 PM

I agree with Curran on it possibly not being pre-edo, but I agree with Christian on the material - there are a LOT of pieces out there that are some kind of "copper" that has been patinated black (the copper is in quotes because its not that highly refined - its not like you're gonna buy the highest grade suaka if you're price point won't let you use shakudo).  Brian T. pointed out to me a while back how prevalent this is....  can you look at the piece in hand to see if the worn spots are trying to heal themselves?

 

Best,

rkg

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#6 johnnyi

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Posted 13 September 2017 - 08:00 PM

Attached File  Still001.bmp   900.05KB   35 downloadsAttached File  Still002.bmp   900.05KB   20 downloadsAttached File  Still003.bmp   900.05KB   19 downloads

 

 

 

 

Richard, I don't have the experience to tell when wear is coming or going, but I've taken some pictures at about 200x which might tell you? The tsuba appears black in hand except for the areas on the seppa dai. Under magnification though it looks entirely different.

 

The first picture  is in the area of the tiny dots upper right design.

 

One picture is of the area in the right of seppa dai

 

the last is the tiny dots upper left.  

 

Thanks again for your help

 

Kind regards,  John

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#7 TosoguCz

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Posted 14 September 2017 - 08:35 PM

I agree with Curran on it possibly not being pre-edo, but I agree with Christian on the material - there are a LOT of pieces out there that are some kind of "copper" that has been patinated black (the copper is in quotes because its not that highly refined - its not like you're gonna buy the highest grade suaka if you're price point won't let you use shakudo).  Brian T. pointed out to me a while back how prevalent this is....  can you look at the piece in hand to see if the worn spots are trying to heal themselves?

 

Best,

rkg

(Richard George)

As I realized these alloys were used for cast pieces. I doubt it was used for handmade pieces.


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#8 BulletSprinkler

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Posted 14 September 2017 - 10:18 PM

 Brian T. pointed out to me a while back how prevalent this is....  can you look at the piece in hand to see if the worn spots are trying to heal themselves?

 

 

Shakudo will not naturally repatinate in oxygen. It is patinated through a chemical process involving a mixture called rokusho.


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Jay


#9 nagamaki - Franco

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Posted 14 September 2017 - 10:33 PM

After repeatedly viewing this tsuba I'm beginning to think it could be brown shakudo.


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_________
Regards,

Franco

#10 Geraint

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Posted 15 September 2017 - 01:56 PM

Dear Jay.

 

 

Shakudo will not naturally repatinate in oxygen. It is patinated through a chemical process involving a mixture called rokusho.

 

I'm not sure this is always so, though of course the original patination is done this way.  I have a wakizashi which was sold to me as having a copper tsuba and sure enough, when it arrived the tsuba was bright copper coloured.  I had some hopes when I noticed that the tsuba was a three plate construction with a silver fukurin and, sure enough, over the years the surface has returned to a rich black shakudo with no help from me at all.  Hence Richard's remark about the spots healing themselves.

 

All the best.


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Geraint

#11 nagamaki - Franco

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Posted 15 September 2017 - 06:23 PM

It has always been my understanding from an expert restorer that high quality shakudo will repatinate given time, where lower quality shakudo will not. Another problem with lower grade shakudo where restoration is concerned is that even when treated chemically it often will not repatinate to the original finish, unlike high grade. 

 

 


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Franco

#12 Ford Hallam

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Posted 16 September 2017 - 07:25 PM

After repeatedly viewing this tsuba I'm beginning to think it could be brown shakudo.

 

 

Oh No!!!   :o   I thought I had a handle on this, what's 'brown shakudo'?


 

 


#13 nagamaki - Franco

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Posted 16 September 2017 - 09:36 PM

Brown shakudo, not a true shakudo, my understanding is copper with a very small percentage of gold plus silver and even pickled with a different chemical, not rokusho. Does not repatinate well.

Yes, no?


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Franco

#14 johnnyi

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Posted 16 September 2017 - 11:08 PM

Ah, Ford, since you're here, please tell me if you think it is any form of shakudo (please do not feel you must be diplomatic! :)

 

 

 

 

 

 

regards, Johni



#15 Ford Hallam

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Posted 17 September 2017 - 03:00 PM

Hi Johni, Franco

 

In my opinion, Johni, your tsuba is a true shakudo. Based on a few dozen analyses I've done of similar pieces I'd say it contains between 0.5 to 1% gold, probably a similar amount of silver and around 0.5 to 0.8% arsenic. I would be very surprised if those copper patina patches didn't come back to a good black, however, they won't while that copper patina is protecting what's underneath. It may be that copper seppa caused the rubbing and there is now more copper on the surface then when it was new.

 

The arsenic is almost certainly a deliberate addition, it's part of a pre-alloy that was made prior to the addition of the gold and silver. This procedure is described in older texts.

 

I've now amassed a few dozen analyses of shakudo pieces, Ko-mino, Ko-goto, and the rest, right through to late 19th cent. I can't see any real patterns in terms of age though so calling something Muromachi shakudo is pretty much a spit in the dark in terms of accuracy, imo.

 

The depth of the black patina is not inevitably linked to the gold content. So, a supposed link between 'quality' in terms of patina richness and 'quality' in terms of imagined gold content can't convincingly be made. I have images and analyses of samples with as little as 0.5% gold and one with as much as 7%, It's almost impossible to tell the patina colours apart.

 

I have yet to encounter an antique (pre-1900) shakudo that was only copper and gold. Silver is always present and in probably over 95% of samples there is also a trace of arsenic. The arsenic is important and, I believe, plays an important role in those shakudo that do exhibit a tendency to 'self heal'.

 

The colour of shakudo patina is very much effected by the surface finish of the alloy. Older pieces often have a subtle micro-corroded surface. I believe that this results in the appearance of a deeper black patina as the light it reflects is somewhat diffused whereas a finer mirror finish reflects the light more directly resulting something of a bluish tint.

 

There are many other factors that can be considered when trying to asses old shakudo. Under certain conditions rubbed shakudo can reform more of a copper patina, perhaps a different sort of body chemistry in the last handler of the piece is the key. 

 

All this to say i think we ought to be a lot more cautious and less confidant when judging these things. :)


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#16 johnnyi

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Posted 17 September 2017 - 05:02 PM

Ford, a great help and a wealth of knowledge as always.  Yes, "caution" will be remembered too. Thank you.

 

 

 

Kind regards,   John i


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