The Traditional Yixing Zisha Processing Method

Last update: 2020-05-12

Introduction

It took me like 6 months to gather, validate and understand all the resources about traditional Yixing Zisha processing. However I think now I understand most of it. If you have questions or something you don’t understand then feel free to leave a comment.

And without further Ado let’s get into it…

Traditional Yixing Zisha Processing

There are three things that make Yixing Zisha Pottery unique in the world. The Material, The Processing and the sophisticated way the teapots are made. Previously I wrote about the Main types of Raw ore which is used in Yixing Zisha (you can read it [HERE] ). The main and original material which was Traditionally used is Zini  (You can read more about Zini [HERE] ), but the following processing method can be applied to other kinds of Zisha too, with the exception of Zhuni. I’ll explain each step in detail, but you can use this flow chart as a cheat sheet whenever you wonder about how Zisha Processing is done.

Flowchart of Traditional Yixing Zisha Processing

I got the pictures from [THIS] video, which I highly recommend for you to watch. It shows how a Top Grade Yixing Teapot is made by National Grand Master Ji Yishun (季益顺). I found this video to be the most authentic source in displaying how Zisha Processing is done.

1. Material Selection — 选料 — Xuǎn liào

Selecting The raw materials is the first step in making a good teapot. The potter has to decide what kind of teapot he wants to make, what should be the color and the overall look of the finished work. The Meticulous selection of very specific ore types will be reflected much more on the finished teapot than just sorting the ore by the main categories of Zini, Hongni or Tuanni.

Grand Master Yi looking at Zisha Ore with a magnifying glass
Selecting the raw materials is crucial

In ancient times not much effort was made to sort the raw Zisha ores. Only Masters of the time took the effort to make their own clay recipes. This is how the famous legendary Zisha clays came to existence, such as Tianqingni, Dahongpao, Lipini, etc.

During the Material selection, larger impurities are removed from the ores. However impurities can be embedded in the ore itself. That’s why there is a need for weathering, which is the second step in the processing of Zisha clay.

2. Weathering — 风化 — Fēng huà

Yixing Zisha Processing Weathering on open air under bamboo roofs
Weathering Zisha Clay Outside

After the ore materials are selected they are piled up outside and exposed to the elements. The constant raining, wind, sun exposure makes the ore absorb moisture which results in cracking and the ore getting loose. Usually weathering is done during the summer or winter, because the weather during that time is optimal for breaking down Zisha ore. When the ore is soft enough to be crushed by hand, then it’s ready for the next phase.

Because Zhuni is soluble in water it doesn’t go through a weathering process, as the ore would be just washed away and nothing would be left of it. Instead, they let Zhuni age for a longer time.

3. Crushing — 粉碎 — Fěn suì

Crushing Zisha ore with a stone mallet
The Zisha ore has to be crushed first

In order to make Zisha clay, they need to make a powder out of the weathered ore. Therefore after the  ore is soft enough they use a large hammer to crush it. After that the roughly crushed ore goes through a stone mill, to further crush it into smaller, more uniform particles.

The Crushed ore is further ground by a stone mill into smaller particles
Then the crushed ore is further ground by a stone mill into smaller particles

4. Sieving — 筛分 — Shāi fēn

Sieving Zisha ore to get a consistent granule size
Sieving Zisha ore to get a consistent granule size

After the ore gone through the stone mill it has to be sieved to ensure uniform particle size of the ore dust. At this step, the Potter has to decide what kind of texture he’d like to give to the teapot. The size of the particles is generally referred to as the mesh size (目). A smaller mesh number (30目) gives the pot a rougher look and feels, more texture, while a larger mesh number (80目) results in a smooth surface.

During the Ming and Early Qing Dynasty, the Mesh size was between 26-35, while at the end of the Qing Dynasty, the Mesh size increased to 55-60 Mesh, showing that the general preference shifted towards teapots with a smoother, more refined look. In the Factory 1 era and modern times, with the advancement of technology, the general mesh size further increased to the 60 – 120 Mesh range.

5. Mixing with Water — 水拌 — Shuǐ bàn

Pouring water into a bowl of Fine ore grounds
After the Ore is sieved water has to be added to the ore

After the ore is purified, it is mixed with clean water. The right amount of water has to be added for a certain type of ore, but it’s usually between 15 – 30%. After the water is added some time has to pass so that the ore absorbs the water. When enough time has passed, they stir the mud until reaches the desired texture, then form it into clay blocks.

The ore is sitting in water, to absorb the moisture
The ore has to absorb the moisture from the water

6. Mud Training (I) — 练泥 — Liàn ní

Mud training is a crucial part of Yixing Zisha Processing
Grand Master Ji performs “Mud Training” on the wet clay

After the clay reached the desired texture they’ll put it on a bench and beat it into block shape with a wooden mallet, to remove air and water from the clay, and to keep it for aging. Usually, they do it until the clay looks bright on the “cut surface” when they cut the mud block in half.

7. Aging — 陈腐 — Chén fǔ

Yixing Zisha Clay put away for Aging
Yixing Zisha Clay put away for Aging

They cover these blocks and put them into rooms which’s temperature and humidity is controlled. The clay is left to age for at least 3-6 months, depending on the type of the ore, the aging period could be longer. This step is important to enhance the plasticity of the clay block. During this time organic matter in the clay bodies degrades and dissolved salts come to the surface. After the clay reached its desired plasticity there isn’t much point to age it further, as it doesn’t affect the way the teapot will brew tea.

8. Mud Training (II) — 练泥 — Liàn ní

Mud Training before Zisha clay is used
Mud Training before Zisha clay is used

After the clay aged enough and ready to be used, firstly it has to be “trained”. It is done to remove air and moisture from the clay and most importantly to prevent Flower Glaze (封釉 — efflorescence).

They put the clay body on a wooden bench, and start pounding it with a wooden hammer. They do it until the clay looks bright on the “cut surface” when they cut the mud block in half with a knife. This is an indication, that enough air is eliminated from the clay. Otherwise, bubbles would form during the firing process, and the pot could explode, break.

Usually after mud training the clay is usable for 3 – 6 months. So what people do is they get for example 15kg of clay, they mud train it, and then use up that 15kg of clay for the following month. Meanwhile the rest of the couple tonnes of clay they have is kept aging further.

The Shiny Cut surface after a well performed "Mud Training"
The shiny “Cut Surface” signals that the clay is ready

This step is crucial, and is just as important as the raw ore material, if not even more. Yixing Zisha is famous for its double porosity structure, and it’s this step that determines the secondary porosity of the teapot. A good manual mud training also directly contributes to the patina development speed and the performance of the teapot.

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