When is Shudei No Longer Shudei

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pedant
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Sun Jan 19, 2020 8:26 pm

interesting. i look forward to hearing others' thoughts, but here's my current, uneducated opinion...
Baisao wrote:
Sun Jan 19, 2020 1:07 am
1) must shudei come from Tokoname and nowhere else?
to me, shudei just means japanese red clay, but unless someone tells me otherwise, i assume it's from tokoname. many people call 'modern', iron-doped clay shudei also. the fact that we're even asking these questions means we're not all on the same page in terms of understanding and terminology, so i think you increase your chances of being understood by being more descriptive. i'd call natural shudei from tokoname something like hon shudei, but maybe someone else would just interpret that as real/natural red clay from anywhere. maybe tokoname no hon shudei is even better.
Baisao wrote:
Sun Jan 19, 2020 1:07 am
2) if #1 is No, then what makes mumyoi different than shudei (barring the affect on tea)?
i think red mumyoi clay is shudei even though i never really hear it called that.
how is it different than tokoname shudei? not sure. i bet they look different unfired.
Baisao wrote:
Sun Jan 19, 2020 1:07 am
3) What should the red clay of Hokkaido be called, if not shudei or mumyoi (in the literal meaning of the word, “unknown”)?
hokkaido-dei? hokkaido no shudei? 8-)
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Bok
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Mon Jan 20, 2020 12:03 am

Now it would be interesting what the Japanese themselves have to say about the topic?

I can only compare it to what I am familiar with: Zhuni and Shudei share the exact same characters in Chinese and Japanese (although they are different clays). Reduction fired Zhuni, which I just saw for the first time in person, is still Zhuni, but is deep blueish black. It looks very beautiful by the way. Hongni or Zini woodfired looks dramatically differen to regular firing, yet the clay is still the same.

What I am saying is, what matters for the name should be the material underneath, the rest is processing and firing.
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Baisao
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Mon Jan 20, 2020 12:12 am

Bok wrote:
Mon Jan 20, 2020 12:03 am
Now it would be interesting what the Japanese themselves have to say about the topic?
Unlikely to happen but it would be great!
Bok wrote:
Mon Jan 20, 2020 12:03 am
What I am saying is, what matters for the name should be the material underneath, the rest is processing and firing.
Apparently the consensus is different for Japanese clay: reduction fired shudei is Banko or shidei.

I’d love to see reduction fired zhuni. As you probably know, Banko is brown-black, unsurprisingly unlike the reduction-fired zhuni you described.
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Bok
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Mon Jan 20, 2020 12:21 am

Baisao wrote:
Mon Jan 20, 2020 12:12 am
I’d love to see reduction fired zhuni.
Ohh it was indeed very beautiful. Gunmetal-blue comes close, a colour I am sure US-citizens will be intimately familiar with :lol:
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Mon Jan 20, 2020 7:46 pm

Bok wrote:
Mon Jan 20, 2020 12:21 am
Ohh it was indeed very beautiful. Gunmetal-blue comes close, a colour I am sure US-citizens will be intimately familiar with :lol:
Finally, a clay that will match well with the gun I caress during my sessions :lol:
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Baisao
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Mon Jan 20, 2020 11:47 pm

pedant wrote:
Sun Jan 19, 2020 8:26 pm
i think red mumyoi clay is shudei even though i never really hear it called that.
how is it different than tokoname shudei? not sure. i bet they look different unfired.
They do! According to HOJO, mumyoi is 20% iron. The raw clay is brick red. It’s difficult to work with so it is blended with a local yellow clay (that also fires red) to give it plasticity.
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nasalfrog
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Tue Jan 21, 2020 12:25 pm

Baisao wrote:
Mon Jan 20, 2020 11:47 pm
They do! According to HOJO, mumyoi is 20% iron. The raw clay is brick red. It’s difficult to work with so it is blended with a local yellow clay (that also fires red) to give it plasticity.
I noticed that the Nosaka clay before and after baking looks similar in color to this hon shudei clay used by the artist Yamada Yutaro. I’m guessing most red clay pots are initially yellow? Having grown up in Oklahoma with red clay everywhere, I always assumed that shudei pots were red before baking.

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Supposedly this particular clay was acquired many years ago from rice fields. I have been using this pot and will post about it once I get more familiar with it. I am really liking the results of the clay & low-profile design on my tea so far. The pour is also super fast.
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Sun Jan 10, 2021 11:46 pm

Chip wrote:
Sat Jan 18, 2020 7:35 pm
A little late to this party ... I am pleased to see the value increasing of all Yamada Sou kyusu!

Relevant to the rabbit trail regarding shudei &/or mayake. What is 100% proper? I really do not know.

However ... submitted for your consideration ... here are 2 Yamada Sou mayake kyusu. Occasionally, one is available that exhibits its shudei roots ... both inside and out. I am guessing placement in the kiln is a logical explanation.

Another, I could make an argument that the clays used are different. The more shudei kyusu being Tokoname and the more mayake kyusu possibly being Shigaraki or other origin. There subtle differences, and Toro thought his mayake might be Shigaraki.

I apologize for the bad lighting, but I wanted to post. Again, these are both mayake kyusu by Yamada Sou.


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Pinging an old thread because i got more information about this recently from Toru:
I heard that Sou had to blend Shigaraki clay which is more fire resistant for wood-firing.

His blended shudei clay is not usually used for wood-firing without blending.
Sou adds iron oxide into his clay for obtaining the shudei color
smx
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Wed Jan 13, 2021 4:01 am

This is a quite interesting topic, especially as I have a Bigetsu Banko kyusu, where Florent from TdJ is writing about:
the clay he uses: red “akatsuchi”, which he makes himself. It is very finely sieved and ripened for many years. With this type of clay, the length of the ripening period is crucial.
With its extremely fine grain, and after having been fired in reduction twice, this clay becomes a superb purple “shidei”, typical of Banko-yaki
Until now I thought, that similar to Yixing, Shudei (as the counterpart to "Zhuni", "red clay") is something different to Shidei (as "Zini/Zisha", "purple clay", more porous etc.), but it seems the nomenclature refers to the optical appearance.

AozoraE wrote:
Thu Jan 16, 2020 6:58 pm
If you're looking for shudei for its effects on tea, you ought to look for shudei that has been fired in a electric or gas kiln. Reason being is that you're not going to get see much of a different in tea brewed in a wood fired pot vs something like porcelain or glass. Wood fired pots are known for having a more neutral effect on tea and therefore are going to act a bit differently from an un-glazed pot fired in a conventional kiln.
Is an explanation possible for this? what happens to the inner surface of the pot and the clay during wood-firing so that the clay no longer has such an effect on the tea? Or do the chemical (?) properties of the clay change because fired at different temperatures or something?
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Wed Jan 13, 2021 6:35 am

smx wrote:
Wed Jan 13, 2021 4:01 am
AozoraE wrote:
Thu Jan 16, 2020 6:58 pm
If you're looking for shudei for its effects on tea, you ought to look for shudei that has been fired in a electric or gas kiln. Reason being is that you're not going to get see much of a different in tea brewed in a wood fired pot vs something like porcelain or glass. Wood fired pots are known for having a more neutral effect on tea and therefore are going to act a bit differently from an un-glazed pot fired in a conventional kiln.
Is an explanation possible for this? what happens to the inner surface of the pot and the clay during wood-firing so that the clay no longer has such an effect on the tea? Or do the chemical (?) properties of the clay change because fired at different temperatures or something?
Regarding wood vs gas firing, the temperature is often similar but the duration is much longer for wood (less than one day for gas compared to several days of continuous wood firing). The claim i often hear is that the wood firing would then cause more surface vitrification, which means greatly reduced porosity. Greatly reduced porosity implies less clay surface area touching the tea. Additionally, I heard that wood firing tends to be more like reduction firing unless specific steps are taken to enrich the area with oxygen.

Based on my personal experience, i don't agee with @AozoraE. I have a wood fired Taiwanese teapot and it 100% has a major effect on roasted oolong compared to porcelain. In my case, the edge structures of the roasted tea is smoothened and the sweetness and aromas are deepened to a great degree.

Below is an interior picture of my woodfired pot. You can visually tell it looks more vitrified as if parts of the interior, but not all of it, almost looks glazed.
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Baisao
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Wed Jan 13, 2021 11:24 am

“Is an explanation possible for this? what happens to the inner surface of the pot and the clay during wood-firing so that the clay no longer has such an effect on the tea? Or do the chemical (?) properties of the clay change because fired at different temperatures or something?”

It has to do with what happens to the iron in these clays when they undergo reduction firing vs oxidative firing. We know that iron and tea react in some way, and we know that the iron in clay changes when fired in the presence/absence of oxygen. It’s no coincidence that we are discussing iron rich clays.
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Thu Jan 14, 2021 7:45 am

LeoFox wrote:
Sun Jan 10, 2021 11:46 pm
Chip wrote:
Sat Jan 18, 2020 7:35 pm
A little late to this party ... I am pleased to see the value increasing of all Yamada Sou kyusu!

Relevant to the rabbit trail regarding shudei &/or mayake. What is 100% proper? I really do not know.

However ... submitted for your consideration ... here are 2 Yamada Sou mayake kyusu. Occasionally, one is available that exhibits its shudei roots ... both inside and out. I am guessing placement in the kiln is a logical explanation.

Another, I could make an argument that the clays used are different. The more shudei kyusu being Tokoname and the more mayake kyusu possibly being Shigaraki or other origin. There subtle differences, and Toro thought his mayake might be Shigaraki.

I apologize for the bad lighting, but I wanted to post. Again, these are both mayake kyusu by Yamada Sou.


Image

Image

Image

Image
Pinging an old thread because i got more information about this recently from Toru:
I heard that Sou had to blend Shigaraki clay which is more fire resistant for wood-firing.

His blended shudei clay is not usually used for wood-firing without blending.
Sou adds iron oxide into his clay for obtaining the shudei color
More info from toru! I was asking him specifically about a wood fired yamada sou i had recently purchased. Picture is below.

Hi Leo,

Thank you for your further inquiry.

In reply to your question, please note as follows:

1.) Does this mean that the clay is natural clay since there is no added iron? 

Yes, it is natural clay.

2.) If it is natural red clay, can this be considered "hon-shudei"?

Hon-shudei refers to Tokoname clay which is rich in natural minerals, ie. does not have any iron added.

The color turns red under oxidized firing.

The same clay will turn a greyish color etc. under de-oxidized firing so the term reflect the color of the fired pieces.

(Please refer to teapots by Gafu on my website which are made with clay with no added iron and are a greyish color.

Gafu prefers not to call his shudei teapots Hon-shudei, even though he processes his only shudei clay without iron added.)

As you may know, many craftsmen in Tokoname spend time blending their clay and experimenting with different components in order to get the desired aesthetic effect.

Therefore , as "Hon" means "real", they do not recognize this term as it implies that any other clay is somehow inferior, which is not the case.


3.) There is no shigaraki clay in this blend?

No, he said Tokoname blended clay.


I heard rumor that Jozan III collected large amount of hon shudei for his family to use. That is why I was surprised that maybe iron was being added into the clay.

I can't really comment on this as I don't know whether the rumor has any substance.

I own a shudei kyusu by Jozan III which is very red and looks as if iron oxide was added to the clay.


Hope this helps,


Best regards,

Toru
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Baisao
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Thu Jan 14, 2021 10:08 am

Good to know! As for Jozan III, Some are red and some are orange. The Jozan II kyusu I have is orange and one of the Emu Yamada kyusu I have is less red than the Jozan III pot it sits next to. Was iron added or did some clay have more iron than others? I cannot say.
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