glazed pot from Tree House Bonsai , bonsai ceramics

Exploring the Aesthetics and Techniques of Bonsai Ceramics

As a fine arts graduate from Alfred University in New York City, a world-renowned school for ceramic arts, I have a background in ceramics that may offer some unique insight into the techniques and production of bonsai ceramics. While it is not necessary to memorize specific makers or their names, understanding the fundamental aspects of bonsai ceramics is crucial to understand the relationship between trees and pots. In this article, we will explore the aesthetics and techniques of bonsai ceramics that can be applied to any ceramics wherever they are from and what to look for when purchasing a pot. It is not just about buying a pot from a famous maker; it is about understanding the aesthetics and techniques involved in the process of making and using the pot. We will start by discussing glazed versus unglazed pots. By the end of this article, you will have a deeper understanding of bonsai ceramics and what makes them unique. Let us jump in!

Unglazed pots 

Unglazed pots are made of various clay bodies and fired to a high temperature, resulting in what's referred to as stoneware, which is stronger and less porous than earthenware and as such more resistant to freezing temperatures. 

Understanding Stoneware in Bonsai: Why It's Important

It is important to recognize that high quality ceramic pots used in bonsai are typically referred to as stoneware, as they are fired to a point where they become as hard as stone. This firing process makes them more resistant to issues such as freeze-thaw damage, which can cause water to enter into the clay body and lead to cracking. Stoneware pots are less porous once they have been fired to a high temperature, which makes them ideal for use in bonsai, as they are less likely to retain excess water and allow for better drainage. Most of the ceramic pots used in bonsai have likely undergone this firing process, making them stoneware.

Stoneware clay comes in different colors, but the colors are based on the material that the clay is made of, and professional ceramicists choose their clay bodies based on tactile quality.
The different clay colors of unglazed pots are mostly for aesthetic purposes, which lend themselves to the feel of the pot or the texture of the skin. The feel of the pot is not just how it feels in your hand but the feeling that you get from its texture, its skin. For instance, a pot with a drier feel to it has a bit of texture, while a pot with a satin finish has a smoother texture. The aging process of a pot also affects its patina, which is how old it feels. The patina of an older pot is smoother, richer, and more moist, while that of a new pot is dry and has a rougher feel.

Patina: the Key to expensive Bonsai Ceramics

The quality of patina on unglazed pots is significant because it expresses the passage of time, which is an essential component of bonsai culture. The residue of the passage of time is a philosophical idea in bonsai culture that cannot be faked quickly. The textures of bark and the patina of older pots carry a high value because they express the passage of time. In contrast, mass-produced unglazed pots have a lower value because they lack the clean, straight, and crisp lines that characterize high-quality unglazed pots in addition to a lack the above mentioned patina. The tactile quality and patina of unglazed pots make them an essential component of bonsai culture.

Considerations for Cracks and Blemishes when choosing a pot

It is an oxymoron to suggest that you will find a perfect antique, especially when it comes to ceramics that are stored and used outside, and are at varying levels of age such as 20 years, 30 years, 50 years, or 100 years. In Japan, it is assumed that all ceramics used outside will have blemishes due to age and use, whereas in the West, perfection is often expected. Chips and cracks are considered differently, with chips being less of an issue as long as they are not new and don’t stand out too much. However, cracks are seen as potentially problematic and may lead to failure, especially in cold climates. Pots with cracks can still be valuable, but extra care must be taken when handling them and during colder months to prevent further damage. When choosing a front for a pot, the least noticeable blemishes should be taken into consideration. Ultimately, with careful handling, a pot with a crack can still last a long time.

A guide to distinguishing the prices of unglazed ceramics

Here are three pots from three different makers: Yamaaki, Reihou, and Shuzan. Despite having the same design of a soft corner, centered bamboo band rectangles, they have very different price ranges. So what makes them different in price? It's their texture and build. The fundamental relationship between the maker and the value or price of the pot is mostly determined by the techniques and skills involved in producing the product. For example, a pot that is mass-produced through a machine press mold could be created 500 times over in 30 minutes, while a handmade pot could take one person three weeks to create. The level of skill involved in handmade pottery is vastly different and reflected in the price.

An older pot with more patina feels smoother and has a richer, more moist feeling, especially on the edges where it has been worn down by use. In contrast, a brand new pot feels dry to the touch. The quality of the lines on a pot also indicates its value - a mass-produced pot made through a press mold may have lines that are not clean, straight or crisp, and may have an unpleasant sandpaper-like texture.

Glazed pots

When it comes to glazed pots, many of the same concerns that apply to unglazed pots still apply, such as blemishes, chips, and cracks.

The art of Glaze

With glazed pots, the chemistry of the glaze is also a major concern. Glaze is a chemical structure that, when fired, is transformed into glass, and the colors in the glaze are based on the chemicals used in its composition. Glaze chemistry is very complicated, with universities offering multiple semesters of study in glaze calc classes alone.

Patina in Glazed Pots: Color vs Texture

Patina is also a concern with glazed pots, but it is more of an issue of color than texture. The texture of a glazed pot does not change as it is covered with glass, but the color can develop a patina over time. The color of the glaze is the most important factor in determining the value and desirability of a glazed pot, with a skilled maker being able to control the color and glaze application. In a nutshell and as a basic guide when it comes to patina on glazed pots color is the primary concern and accounts for 90% of it, while texture only accounts for 10%. On the other hand, for non-glazed pots, texture is the main concern and accounts for 90%, while color is only 10% of the concern.

An analysis of 3 glazed pots

When examining a glazed pot, there are certain faults in improper glaze application that can be observed.

"Koyo" Pot

For example, unmitigated dripping, where drips are so big that they drip onto the kiln shelf is a sign of a lack of skill in controlling the glaze. However, skilled dripping where the glaze drips down past the edge of the pot but falls short of dripping completely off is a sign of highly technical skill in glaze application.

Control of the glaze application is also seen in the absence of drips on the outside of Koyo pots but consistent drip edges on the inside lip.

If the glaze is applied too thinly on the flat surfaces of the pot, it will create thin marks that visually weaken the quality of the glaze. This is an indication of improper technique and should reduce the value of the pot. A skilled application of glaze should result in a consistent thickness across all surfaces.

When using certain glazes, such as green-blue crystal glazes, it's common to see a lighter-colored edge on the pot. This occurs because the glaze pulls away from the edge as it melts, which is actually a sign of proper glaze application. In this case, the glaze pools on the flat surfaces and thins on the edges. However, if you notice thinner and weaker coloring on the flat surfaces, it would be an indication of improper glaze application.

"Shuhou" Pot

If you examine a "Shuhou" pot below and notice pock marks on the glaze, it's intentional and adds value to the pot. Shuhou is known for having pockmarked glaze, which contributes to the quality of the patina and texture. Therefore, the pock marks are intentional and serve a purpose.

"Reihou" Pot 

The pock marks on this particular "Reihou" pot below were not intentional. They were a result of dust being present on the surface of the pot during the second glaze firing, which prevented the glaze from adhering to the clay body and created the marks.

To summarize, when evaluating glazed ceramics, the focus is more on visual patina than texture. It's important to look for unintentional pock marks, uncontrolled drips, and thin spots in the glaze application where the clay body is visible. These are the main concerns when examining glazed ceramics.

The quality of the clay body, production techniques, textures, visual appearance, and patinas of glazed versus unglazed ceramics are all important factors to consider when analyzing ceramic pots. It is essential to develop the ability to troubleshoot and evaluate pots for their value, rather than simply relying on name recognition. By understanding these topics, you can confidently assess ceramic pots and make informed purchasing decisions.

Kokufu ten 2024, Kokufu exhibition 2024, 98th Kokufu ten, bonsai exhibition tokyo

Visit Tree House Bonsai during the next Kokufu-ten

During the Kokufu exhibition in February 2024, Adam will open the doors of Tree House Bonsai. Join us for a half-day, all-inclusive tour from Ueno on February 11th and February 14th.