From their elegant shapes to their captivating glazes, tenmoku have ensnared the eyes and hearts of tea lovers for a thousand years. Throughout this millennium, they have served as symbols of wealth, status, and the pinnacle of cultural refinement, setting the stage for the aesthetic development of tea culture in Japan. Considered the most formal of chawan and representing the elegance and sophistication of Song Dynasty Chinese culture, tenmoku are treated with the highest level of reverence and respect—being used to serve tea to nobles or offer tea to kami or the Buddha. The most exquisite examples are designated National Treasures of Japan and many can be found in museums across the globe.

In part one of this guide, we’ll explore where this style came from and how they came to occupy such a unique position in Japan's material culture. Part 2 will cover the types, classification, and use of these bowls as well as their accompanying lacquer stands.

I’m also here to set the record straight about some terminology, but before we get into that, let’s roughly outline what a tenmoku is.

What are Tenmoku?

 

Fig. 1: A Song Dynasty ‘Nogime’ Tenmoku with Carved Lacquer Dai

Defining tenmoku is difficult as the definition has drifted over the centuries, as we'll soon see, but here are some loose guidelines before we dive into the deep end. 

1. Broadly speaking, tenmoku (天目) are tea bowls with a deep, conical shape; a small foot; and an indented and flaring lip
   
2. Narrowly speaking, tenmoku are bowls of this shape with a dark, iron-rich glaze
   
3. Even more narrowly speaking, ‘real’ tenmoku are bowls of this shape and glaze fired in Song Dynasty China, especially those from the Jian Kilns
   
4. And even more narrowly speaking, those bowls actually don’t count as tenmoku at all…you see how this gets confusing?

Additionally, the term tenmoku is applied separately to the aforementioned shape (tenmoku-gata [天目型]) or the glaze (tenmoku-yu [天目釉]). In fact, ‘tenmoku’, often spelled ‘temmoku’ is used in western pottery for a type of iron rich glaze inspired by these bowls.

Fig. 2: A modern Tenmoku-gata bowl with a non-tenmoku glaze - by Touan

Shape

Fig. 3: Tenmoku Shape

The key points of this shape are the small and short foot, the subtle curve to the conical body, and the balance of the constriction and flare of the lip. Generally speaking, Chinese tenmoku have more subtle implementations of these features, especially when it comes to the lip, with many surviving examples merely hinting at an indent. Conversely, both historical and contemporary Japanese-made tenmoku tend to have a more exaggerated indentation. It is thought that this feature is not merely aesthetic, but provides two practical  benefits: on the outside, it provides a comfortable drinking lip and on the inside, the indent helps prevent whisked tea from splashing out.

The elegance of this shape lies in the tension between their small foot and their expansive and flaring lip. This tension, however, does make these bowls inherently more unstable than others, which is one reason they are invariably paired with a stand called a tenmoku-dai (天目台). More on these in part 2.

While the subtleties of the shape vary slightly, the size of tenmoku is relatively consistent, with most being on the smaller size for a chawan: about 11-13cm in diameter and 6-7cm tall.

For reasons you’ll understand shortly, some chajin (茶人 - tea ceremony practitioners), including myself, prefer to use the word tenmoku as a noun, rather than as an adjective, i.e. “tenmoku” vs “tenmoku chawan”, but the latter is more common today. Now with that rough explanation out of the way, let’s dive deeper into where this style came from, how they’re made, and what makes them so special. 

History of Tenmoku

Before Tenmoku

The story of tenmoku starts outside of Japan, before the development of matcha, and a little before the invention of these bowls themselves—we’re going back to Tang Dynasty China (618–907 CE). 

Fig. 4: Song Dynasty copy of Xiao Yi Trying to Swipe the Langting Scroll

As I’ll explore in detail in a future blog post, in both Japan and China, tea during this period was crushed into a coarse powder, boiled with salt in a pot, and the decoction was ladled into cups or bowls for drinking. Like modern steeped green tea, this tea was translucent and had a golden hue that was best appreciated in light-coloured ceramics, so celadon, porcelain, and even glass wares were ideal. In his legendary 762 work, the Classic of Tea (茶經 - Cha Jing), Yu Lu writes:

The colour of the bowl is valued when it is green; green enhances the color of the tea.

Additionally, most Tang-era tea vessels were thin, wide, and shallow; perhaps to allow the freshly boiled tea to cool quickly and to appreciate the colour.

Fig. 5: Tang Dynasty Porcelain Boiled Tea Set

In both contemporary iconography and surviving artefacts, light-coloured, shallow bowls paired with wood, lacquer, metal, or ceramic stands/saucers are the de facto teaware in this time period. This pairing of tea bowl and stand continues into the next dynasty.

Diancha and Chasan

In the subsequent Song Dynasty (960–1279), this boiled tea method gave way to a new style of tea preparation: whisked tea or dian cha (点茶) in Chinese¹. This dian cha was the precursor to modern matcha; unshaded and processed differently, it whisked into a more whitish-yellowish foam than the vibrant green we know and love today.

Fig. 6: Modern Reconstruction of Dian cha

To better showcase this whitish foam, tea enthusiasts moved away from light-coloured celadon and porcelain to dark-glazed wares which provided better contrast. The preference also shifted to deeper bowls with thicker glazes: better for whisking in and also better for retaining heat. After all, the tea was no longer directly boiled and all that whisking saps a lot of heat out of it.

This new style of deep, dark-glazed tea bowl is what would become known as tenmoku in Japan. A few kilns in China started producing these bowls, but none were as successful as the kilns at Jian’ang in modern-day Fujian province. 

Fig. 7: Song Dynasty Jian Ware Tea Bowl (Nogime Tenmoku)

The first reference to Jian Ware in the written record comes from a brief mention by Tao Gu in the mid-900s.

Tea bowls made in Fujian are patterned with partridge spots, and are treasured by tea connoisseurs

One century later, these bowls are more than just treasured: they are exalted as the best of the best. Tea master Cai Xiang, in his treatise The Record of Tea from 1049, writes:

Tea is of light colour and looks best in black bowls. The bowls made at Jian’ang are bluish-black in colour, marked like the fur of a hare. Being rather thick, they retain the heat, so that when once warmed through they cool very slowly, and they are additionally valued on this account. None of the bowls produced at other places can rival these. Celadon and porcelain bowls are not used by those who give tea-tasting parties.

The hare’s fur markings and blue-black glaze can be seen on many Jian bowls (Fig. 6) Though Cai Xiang mentions the light-coloured foam in his Record of Tea, there is no mention of a bamboo whisk or chasen. Instead he talks about whisking the tea with a gold, silver, or iron spoon. It is thought that this spoon mixing is why many old tenmoku have scratches on the inside.

Fig. 8: Tea Drinking Scene, 500 Arhats, Song Dynasty 12th Century (Daitoku-ji)

In both these texts, the authors use the Chinese term zhan or chazhan (盞・茶盞) instead of the earlier chawan (茶碗 - tea bowl) used by Yu Lu. This is a rather pivotal moment in the history of tea bowls as the wan (椀・碗) in chawan is the generic word for bowl, and in the early days of boiled tea, tea was often made in borrowed wares such as wine bowls.

Zhan, on the other hand, denotes a somewhat more specialised usage and the term chazhan began being used almost exclusively for bowls designed for dian cha, whisked tea, implying that these were more specialised tea wares. 

Unsurprisingly, zhan made at the Jian kilns were called Jianzhan (建盞). These dark bowls also begin appearing in paintings from this time (Fig. 8). From the iconography, it seems that the pairing of dark jianzhan with a red lacquer stand was the most common.

The term zhan is used again in another important writing from this period, this time from Emperor Song Huizong (宋徽宗) in his 1107 Treatise on Tea (大观茶论)

The color of the tea bowl (zhan) is prized when it is bluish-black. Those with distinct and evenly distributed jade hairs resembling hare’s fur are considered the finest. This is because such a colour and luster best bring out the brilliance of the tea’s hue when whisked. The base must be somewhat deep and slightly wide. If the base is deep, the tea stands up well and the foam is easily produced; if it is wide, the whisk can move freely without obstruction during the beating and stirring.

Emperor Huizhong doesn’t mention Jian ware by name, but clearly describes dark bowls with rabbit’s fur glazes, just like Cai Xiang did. The glaze effect on the bowls pictured in Fig. 1 and Fig. 7 are often described as ‘rabbit's fur’ to this day. Later in the treatise, the Emperor also mentions bamboo whisks, so no more scratching up your nice bowl with metal spoons.

Thus, with the Song Emperor writing their praises, dark-glazed chazhan, and especially jianzhan from Jian’ang were cemented as the aesthetic pinnacle of teaware.

Now, let's shift our focus back over the sea to medieval Japan in the 1100s, where Chinese culture was all the rage amongst the aristocracy.

Yōsai and the first Tenmoku in Japan

The standard, simplified tale is that tea plants, tea bowls, whisked tea culture, and Rinzai Zen buddhism were brought to Japan all at once from Song Dynasty China in 1191 by Zen monk Myōan Yōsai² (明菴栄西), but recent research has added some complexity and context to this traditional story. Of course, Yōsai is undoubtedly one of the most important figures in Japanese tea and cultural history, but even so, he cannot be credited with single-handedly introducing tenmoku, matcha, and Zen to Japan.

The discovery of a tenmoku bowl in an archaeological excavation in Hakata (present-day Fukuoka) that dates to the late 11th century³ pushes back the arrival of these bowls in Japan by about 100 years. It is thought that the port city of Hakata, which was one of the primary ports of trade with China, was home to many Chinese immigrants, so it makes sense that the new styles of tea culture and teaware would appear there first. 

There is no record of Yōsai himself bringing back bowls from China, but he does briefly mention them in his seminal work from 1211: Kissa Yōjōki  (喫茶養生記 - Drink Tea for a Long Life). Here, he annotates a Chinese poem about tea, saying,

Ou is a fancy name for a chasan, with a wide mouth and a narrow bottom. To prevent the tea from cooling too quickly, the bottom of the vessel is narrow and deep.

Here, Yōsai is translating ‘Ou’ (甌) , a poetic term, into chasan for tea bowl, which is the Japanese reading of chazhan. From his description of the shape, it is clear that Yōsai is describing the same chasan praised in the earlier Chinese texts. Yōsai’s book helped introduce whisked tea culture beyond the aristocracy and to the warrior class in particular, which ushered in an explosion in tea’s popularity in Japan, and thus a huge rise in demand for these chasan. Before this, tea drinking in Japan was mostly limited to monks and the nobility.

Throughout the 1200s and 1300s, chasan were imported en masse from China to feed this new demand. So much so, that chasan and their stands begin to appear in Japanese painted works. Most textual references to these new Chinese bowls use the word kensan which is the Japanese reading of jianzhan: tea bowls from Jian kilns. While kensan dominate the written record, archaeological excavation has revealed they only accounted for about half of the chasan in Hakata, with the rest coming from other kilns in China.

Sinan Shipwreck

Fig. 9: Artefacts from the Sinan Shipwreck at the Korea Maritime Museum

For centuries, we only had the few surviving artefacts to support the written records as evidence of the mass import of Chinese ceramics into Japan. This changed in 1975 when the wreck of a Chinese trade vessel was found off the coast of South Korea. Upon analysis, the boat was dated to 1323: the year it left Ningbo in Yuan Dynasty China, and sank en route to Hakata with items on board destined for the temples of Kyoto. 

Fig. 10: Kensan from the Sinan Shipwreck

Of the 20,000 ceramics on board, mostly celadons, there were some 500 or so tenmoku pieces, some kensan and some other chasan from other kilns in China. These tea bowls were likely destined for nobles, samurai, and monasteries, as these were the only classes that could afford such Chinese luxuries. Interestingly, all the tenmoku on this boat were second-hand antiques with signs of use. This is because by 1323, whisked tea was moving out of fashion in China, where steeping tea in tea pots was the new fad. As such, no one was making any more tenmoku in China.

The word “Tenmoku”

So far, for these first 400 or so years of history, we’ve seen these bowls called san, chasan, or kensan, in the case of Jian ware. So, you might be thinking, why on earth do we call them ‘tenmoku’?! 

Throughout Japanese history, many Buddhist monks travelled to China to study the dharma and bring back new teachings and practices to Japan. Tea itself, being a fantastic meditative aid due to its caffeine and theanine content, was perhaps originally brought to Japan on one such monastic trip. In the 12–1300s, some of these journeying monks practised Zen at temples on Tianmu Mountain (天目山) in Zhejiang province and brought chasan from these temples or from shops nearby, back to Japan. In Japanese, tianmu is read as tenmoku and so these bowls were called tenmokusan (天目盞). The first time this term appears in the written record is in 1335.

Domestic Tenmoku

Fig. 11: Seto Tenmoku - mid-1400s

Despite the huge influx of tea bowls from itinerant monks and ships loaded with ceramics, this still wasn’t enough to keep up with demand, so kilns in Seto, Aichi Prefecture began to produce domestic copies in the late 1200s. Their formulation of an iron-rich glaze became what we now call ko-seto (古瀬戸 - old-seto). Seto continued production of tenmoku well into the 1700s, with many variations in shape and glaze.

Even then, this wasn’t enough to satisfy growing demand, and lacquered wooden bowls in the same shape were also made. In addition to a few rare surviving examples, there are many such bowls depicted in scrolls and screens in the 13–1400s. The production of such affordable and accessible ‘replicas’ for the lay people only helped to elevate the original imported kensan and tenmoku to an even higher status.

Karamono-suki

Fig. 12: Imported dai-tenmoku and celadon on display, The Story of Fukutomi, mid-1400s (Cleveland Museum of Art)

The vogue of imported Chinese ceramics, including tenmoku, became known as karamono-suki (唐物数寄 - discernment for Chinese wares). Owning, displaying, and understanding karamono was a means of showing wealth, power, and cultural authority through their connection to China and Zen culture, especially for the samurai class who rose to power once again with the Ashikaga Shōgunate in the 1300s.

As this taste developed among the warriors, tea culture was undergoing an explosion in growth and a diversification in practice—once limited to nobles and monks, tea was now sold by street vendors in tenmoku, served at tea guessing games at lavish parties, and became part of hospitality etiquette.

For the warrior elite, this hospitality aspect gave them an excuse to show off their expensive Chinese teaware. It’s like using your fine china for when the Queen comes for tea, except in this case it’s the Emperor, and by this case, I mean the 1437 formal visit of Emperor Go-Hanazono to the Shōgun Ashikaga Yoshinori’s Muromachi Palace. 

The decoration record for this visit⁴, which is an amazing insight into the tea culture of this time, records no less than 31 kensan on display in 5 different rooms in 3 buildings. Additionally, there were 2 yuteki, and 3 usan. What are those? Ask Nōami (能阿弥), the interior decorator behind this display, as well as the author of this record and tea master and aesthetic advisor to the Shōgun. 

About 30 years later, he and his grandson Sōami (相阿弥) wrote another guidebook on the formal display of Chinese items for different palaces⁵, but this time, he included illustrations and a ranking of tea bowls which changed how we interact with tenmoku ever since.

I’ll dive into that text and the classification of tenmoku in part 2 :)

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¹ Read as tatecha or tencha in Japanese, not to be confused with tencha [碾茶], the raw material for matcha

² Also read Eisai, but Yōsai is probably closer to how he would have said it [Kōzu Asao, 茶の湯の歴史]

³ibid

⁴The Muromachi-dono Gyōkō Okazariki (室町殿行幸御飾記)

⁵ The Kundaikansōchōki (君台観左右帳記) copies of which usually contain display guides/records for the Ogawa Palace (小川殿) and the Higashiyama Palace (東山殿), the latter of which survives, in part, as Jishō-ji/Ginkaku-ji (慈照寺・銀閣寺)