Editorial Conversation: Chapter 8, Section 10: Other Zisha Clay Formulation Techniques - Tiaosha (调砂)

The episode is also available on YouTube and Spotify.
A full transcript is included on the episode page and below:

[00:00:00] Jason Cohen: Hello, everyone. I'm Jason Cohen, the author of an Introduction to the Art and Science of Chinese Tea Ceremony. Today, we're discussing Book 2, Chapter 8, Section 10, Other Zisha Clay Formulation Techniques.

Here to talk about this chapter is our editorial team, Zongjun Li,

[00:00:21] Zongjun Li: Hello,

[00:00:22] Jason Cohen: and Emily Huang.

[00:00:25] Emily Huang: Hi everyone!

[00:00:27] Jason Cohen: Let's start with some definitions for the listeners. Zongjun, what is tiaosha (调砂)?

[00:00:32] Zongjun Li: Tiaosha (调砂) essentially is, if you interpret it literally, it means mixing or blending of grains. So different types of clay, different types of grain size being blend together or mixed together in different manner is essentially what tiaosha (调砂) is.

[00:00:48] Jason Cohen: And how does this manifest in a Yixing teapot?

If a listener was listening to this, how would they know if they were looking at tiaosha (调砂)?

[00:00:56] Zongjun Li: Generally, there are two main characteristic that you can just recognize tiaosha (调砂) immediately both visually and texturally. So visually, for tiaosha (调砂) you would have oftentimes these very artistically designed or beautifully appeared stellar image of a a teapot surface.

Like different color of clay grains scattered across the surface of the teapot in different pattern. We will talk about how these patterns vary in terms of different method later in this podcast. When you see this type of surface on a teapot, it's usually a tiaosha (调砂) work.

And of course, you have other techniques such as chousha (抽砂) which is more texture driven.

[00:01:39] Jason Cohen: We'll talk about chousha (抽砂) in one moment, but you would say that tiaosha (调砂) generally creates a spectacular grainy pattern. It has highly contrasting colors of speckles embedded into a teapot or into a clay body.

[00:01:53] Zongjun Li: That's correct.

[00:01:54] Jason Cohen: Excellent. Emily, what is pusha (铺砂)?

[00:01:57] Emily Huang: So pusha (铺砂), in Chinese pu (铺) means layering on top of similar to tiaosha (调砂) in the sense that it is also mixing, but it is not blending. It would be adding a different type. It could be clay or grains on top of a base type of clay.

[00:02:15] Jason Cohen: And Zongjun, finishing the definitions with you, what is chousha (抽砂)?

[00:02:20] Zongjun Li: Chousha (抽砂) is essentially using different grid size of the sith to remove a medium size grain from a base clay, and then you have only the large size clay and the smaller grain size clay. And then you have this beautiful contrast of different polarized grain size to create this very coarse and interesting surface texture.

[00:02:43] Jason Cohen: And so that's predominantly textural, whereas the other two techniques are predominantly visual.

[00:02:49] Zongjun Li: That's correct.

[00:02:51] Jason Cohen: So in summary, what each of these techniques have in common is a modification of particle sizes through the addition or removal of grains.

And if it's an addition it's often from a different zisha material in the base clay. Do both of you agree? So that seems rather complicated as a technique, right? When did it develop? Is it an old technique?

[00:03:11] Emily Huang: It actually started around Ming dynasty, and it is quite old in the sense of time period, but I would say it really started when the artists were going after a higher form of art, different shapes and colors that they want to play with to come up with a final teapot art.

[00:03:33] Zongjun Li: Yeah, that's correct. At the same time, you also see a lot of development in terms of the artistic design of the teapot itself. These tree trunk or proto gong chun (供春) style teapots slowly emerge. It was at a time that people start to pay attention to the artisanal craftsmanship and the artistic value of teapot. Instead of teapot just being a, a utensil to brew tea.

[00:03:58] Emily Huang: Yeah. Yeah. I definitely wanna add to that. Ming dynasty is also at the height of all the different poetries, arts, calligraphy, and all that. So that was also when a lot of the tea pots, tea drinking, tea ceremonies were embedded into these cultures.

[00:04:18] Jason Cohen: We focused on the visual effects so far in this part of the conversation but are the effect exclusively visual? Is there another reason that ceramic artists would add grains into the material? Is there textural properties or other types of material properties that can be modified with the tiaosha (调砂) additions?

[00:04:39] Zongjun Li: Definitely. Like one part of the tiaosha (调砂) technique is to bring certain materials such as shu sha (熟砂) and in the western term we call it grog into the base clay. It's basically a bisque fired or prefired clay grains in a slightly lower temperature, usually around 600 to 800 degrees Celsius.

And then they will add that pile of bisque fired grain into the base clay to increase oftentimes the structural integrity of the final teapot. So especially for certain clay type that tend to slack or tend to have higher deformation rate, bringing in shu sha (熟砂) definitely has a lot of improvement in terms of its functional utility.

[00:05:24] Jason Cohen: And so when using the same clay type, what's called ben se tiaosha (本色调砂), where there is no visual effect, that's predominantly about modifying texture, about increasing the strength moldability of the wares particularly for larger wares. For yi se tiaosha (异色调砂), for tiaosha (调砂) with contrasting colors, originally when I saw these speckled wares early in my tea education, they were not to my aesthetic preference.

So it took me some time before I started to find tiaosha (调砂) wares attractive and beautiful. Did you go through a similar sequence or was this more of a Chinese or Taiwanese aesthetic? Did this immediately appeal to you or did it take you some time going from pure colored wares to these speckled wares?

[00:06:11] Zongjun Li: Oh, I definitely like yi se tiaosha (异色调砂) in the first place. The contrast of color and also just the sheer you know, it kind of intrigues you to want to touch it. The visual effect and the textural effect really has a thing to me in the very beginning.

I don't know about you, Emily.

[00:06:30] Emily Huang: I have to say that I never found it unusual, the yi se tiaosha (异色调砂) having different color specs visually. But I never wanted to buy it or use because it seems like it's designed and produced for just observing visually, like it should be put into a museum, not in my house.

[00:06:52] Zongjun Li: Yeah, there is definitely a very strong kind of artistic and scholarly preference towards this type of design. Actually, you don't just see that in teapots. In some traditional calligraphy and traditional ink painting, people will put gold foil speckles on the paper to create a textural dynamic of the painting.

[00:07:14] Jason Cohen: Very similar to Japan, where they use the gold dust blown through the bamboo and cloth sea underneath the lacquer to create the speckles.

[00:07:23] Emily Huang: Yeah. Or just to show people how rich you are

[00:07:28] Jason Cohen: Both the yixings and the gold dust lacquer, that type of cultural and aesthetic differences is very interesting, and particularly your comment that the tiaosha (调砂) wares, the yi se tiaosha (异色调砂) wares don't look to be utilitarian. They look to be artistic pieces. And that relates closely back to what you were saying about the origin of yi se tiaosha (异色调砂), that this technique probably developed with the addition of grog into larger format wares as a form of texture modification. And then they realized that you could actually use a contrasting color and blend that in. And that brought it from originally a utilitarian modification of material properties to an artistic practice. I think that's a keen observation that listeners should be aware of. An interesting question rooting from that is, are there any restrictions on what grain material or the processing of the grain material that can be used for tiaosha (调砂)?

Can you just use any base clay and any grains or can you only use some combinations or do you have to process the grains in a certain way in order to use them for tiaosha (调砂) wares?

[00:08:36] Zongjun Li: I'll give it a start. Definitely, shrinkage rate is something that you should consider doing tiaosha (调砂). If the shrinkage rate is too large between the base clay and the grain that you are going to blend in, you are going to have a nightmare, firing those wares because the grain might fell off or it might be crushed by the base clay forming floss.

So definitely for anyone who tend to create a tiaosha (调砂) ware from the beginning, one needs to really master the shrinkage rate of the clays that they're playing with.

[00:09:09] Jason Cohen: What are the common flaws that can occur from a poorly formulated tiaosha (调砂)?

[00:09:14] Zongjun Li: One of the common flaws will be, they call it tuo wei xian xiang (拖尾现象), or dragging tail effect. Basically it's when you have some soft and different colored grain inclusions in your base clay that it's not well mixed and during the Ming Zhen (明针) process or the smoothing process, the grain might be crushed by the scraper and then getting dragged across the entire teapot and leaving a very noticeable mark, which is considered as a common flaw. And other flaws, as I mentioned before, would be the sha (砂) being blend into the base clay, having too much or too little of a shrinkage and then end up being crushed by the base clay or fell off from the base clay, leaving marks.

[00:09:58] Jason Cohen: My next question.

Are there any natural forms of zisha tiaosha (调砂)?

[00:10:03] Emily Huang: Not to our knowledge, no. So there has been some comments on a clay called ziyu jingsha (紫玉金砂) that was saying that it is more of a natural but it actually is not. It is one of the many forms of zini (紫泥) ore. We do see different ores embedded within, but they are not actually artificially blended like what we're talking about right now.

[00:10:28] Jason Cohen: How can you tell the difference between something like tian qing ni (天青泥), which contains lipini (梨皮泥) inclusions versus tiaosha (调砂)? Why isn't that tiaosha (调砂)?

[00:10:38] Emily Huang: That is a very good question.

[00:10:40] Zongjun Li: For tian qing ni (天青泥) with lipi (梨皮) inclusions, definitely, you are not going to have a very homogeneous distribution of lipi (梨皮). It's depending on where the lipi's (梨皮) paragenesis with the tian qing ni (天青泥). You sometimes have very ununiformic distribution of lipi (梨皮), which sometimes some pre-cleaning need to be done before the tian qing ni (天青泥) is ready to turn into a teapot for the ceramist to use.

So, my gut suspicion is that some ceramist in the past got inspired by this natural phenomenon and start to experiment. The end effect is definitely very different with a natural paragenesis clay versus an artificial tiaosha (调砂).

[00:11:23] Jason Cohen: I would say that it's mostly about appearance, that in any naturally formed blend of clay you're going to have little tiny speckles, but the color continue to be quite uniform and so you're not going to have the type of radiance that tiaosha (调砂) has, that spectacular effect where the grains drastically stand out from the background clay. It's much more of an even surface visual appearance.

[00:11:47] Zongjun Li: I have a question for you, Jason.

[00:11:49] Jason Cohen: Go ahead.

[00:11:50] Zongjun Li: What's your current preference of tiaosha (调砂)? And how has your preference changed throughout time?

[00:11:56] Jason Cohen: Now I do appreciate tiaosha (调砂). And particularly I appreciate a lot of the LEQR the late Qing, early ROC, tiaoshas (调砂) that were attempting to recreate early Ming Dynasty style wares. I think the use of really large shihuang (石黄) hard grains, where you can actually see the grain embedded in a little pockmark.

I have a teapot here that's featured in a previous chapter and referenced in this chapter where you can really see the difference in the grain. And sometimes it looks like a grain is loose. Something about it is very appealing, the little fleck of gold embedded in a nice baked zini (紫泥) color.

But I would say that that's a very recent acquisition of preference. I would say that before starting to write this book, I would probably have still preferred the more pure, homogenous appearance more common throughout zisha clay. And I think it's also part of an increased appreciation for zini (紫泥) that I've gained while writing this book. We talked about this in the last chapter, that zini (紫泥) seems to be the least hyped clay, right?

[00:13:12] Zongjun Li: Right. Big old brother.

[00:13:14] Jason Cohen: Yeah, and the tiaosha (调砂), yi se tiaosha (异色调砂) is predominantly done on a zini (调砂) base, with that contrasting shihuang (石黄). Yeah, it's a very new appreciation. I did not have it before starting to write this book and doing the research on this book.

[00:13:29] Zongjun Li: Interesting.

Do you find tiaosha (调砂) having different utility effect to the tea when you brewing tea with your tiaosha (调砂) collections?

[00:13:38] Jason Cohen: So I only have a single teapot that is tiaosha (调砂) and it's actually pu sha (铺砂). So the grains are only on the surface, so there is no difference in effect from other antique zini (调砂).

I've not had much tea out of a pure tiaosha (调砂) with the fully blended grains. My assumption is that there would be relatively little effect. And the reason for that assumption is because the tiaosha (调砂) grains are generally harder, so that they're not crushed, which means that they're predominantly from a denser clay. The most common is shihuang (石黄), but they're usually one of the very firm grains, so shihuang (石黄), shihong (石红). And those are not very porous or textural, so I don't think that they have a large effect.

I actually, and I haven't been able to test this, I actually think that chousha (抽砂), the removal of the mid sized particle sizes, would have by far the largest effect on the tea because the removal of those grains accentuates surface texture. And my theory, which we'll write extensively about in the book with some experimental tests and designs, is that it's really surface texture that's controlling the variations in extraction brew rate, acting as as either a catalyst or a nucleation point or a dampener.

And hypothetically, in theory, it should be chousha (抽砂) that has the largest magnitude of effect. And I think it's a much larger magnitude of effect.

[00:15:02] Zongjun Li: Oh, very interesting. This probably might be our next batch of commission.

[00:15:08] Jason Cohen: Side by side, normal and chousha (抽砂).

[00:15:10] Zongjun Li: That's right.

[00:15:12] Jason Cohen: Our friend is going to think that we're crazy. Let's do another triplet set?

Oh, that would be fun. Yeah, one of each. We would like to do a tiaosha (调砂), a pusha (铺砂), and a chousha (抽砂) and see how it affects the tea. It it would have to be a four part set, right? Because we would need the base clay as well.

[00:15:32] Zongjun Li: Matrix is just getting larger and larger

[00:15:35] Jason Cohen: Yeah, we're all gonna have a lot of deep thoughts. All right my last question, Emily, who is Admiral Grog?

They can't hear you laughing. You're on, you are on mute.

[00:15:47] Emily Huang: It's okay. Okay, Admiral Grog was a British Royal Navy and apparently his name was used for a very common lemon alcohol drinks in the Caribbean.

[00:16:00] Jason Cohen: Yeah, that's, that's approximate.

[00:16:02] Emily Huang: Alcohol?

[00:16:03] Jason Cohen: Yeah, alcoholic. It's a rum punch.

[00:16:05] Emily Huang: Yeah. A British Caribbean rum punch that was named after Admiral Grog.

I've never heard that before this book.

[00:16:13] Jason Cohen: Have you ever spent time in the British Virgin Islands drinking rum punch?

[00:16:16] Emily Huang: Of course not!

[00:16:18] Jason Cohen: Okay, you have your honeymoon planned for you right there. The

[00:16:23] Emily Huang: The Caribbeans 4th of grog.

[00:16:26] Jason Cohen: Zongjun, why is this relevant to the chapter? Why is there a long footnote about Admiral Grog?

[00:16:31] Zongjun Li: Yeah, starting from Ming Dynasty, exchange between the British Empire and China has greatly intensified and the scholarly community developed this preference of drinking rum out of pusha (铺砂) teacup.

I'm totally joking.

[00:16:47] Jason Cohen: Rum, good to the last drop. What did Admiral Grog have to do with the ceramics technique of adding grog, fired clay back into an unfired ware?

[00:16:57] Emily Huang: Nothing.

[00:16:59] Jason Cohen: Nothing. Absolutely nothing. It's just an unfortunate convergence of names.

[00:17:06] Zongjun Li: Unfortunately, it does not. But do you have any idea of where the name came from, Jason?

[00:17:11] Jason Cohen: The actual semantic origin of grog? No. I think grog at some point was a term for sand. But I'm not 100 percent sure of that.

[00:17:20] Zongjun Li: It has definitely nothing to do with the drink or Admiral Grog from the British Navy.

[00:17:26] Jason Cohen: That's more likely to have sand in your rum punch in the BVIs. Everyone, that's all the time that we have for today. Thank you for joining us of this edition in Tea Technique Editorial Conversations.

Please join us again for our next conversation, Construction of Yixing Teapots.