Japanese ceramics: clay, glaze and form

Ceramics are made by shaping earthy materials and firing them hard. The body is the material beneath any glaze: low-fired earthenware is relatively porous, while high-fired stoneware is denser. Porcelain typically has a pale, dense body that can transmit light when thin. Japanese tōki may include stoneware, so it does not map neatly onto English earthenware. A white surface can also come from glaze or a clay slip rather than a porcelain body.

Mino names a production region, while Shino identifies a type of pottery associated with it. Kakiemon style describes a ceramic style; not every example was made at the Kakiemon family kiln. An object label may separately identify an individual maker. Place, material, technique, style and authorship describe different aspects of the same piece.

Hand modelling shapes the clay directly. Coiling joins successive ropes of clay, while slab building joins flattened sheets and can make angular forms. Throwing raises and shapes clay on a rotating wheel. Moulds can receive pressed clay or liquid slip. Potters choose and combine these methods according to the body and the intended form.

Kōransha describes a sequence for its Arita porcelain. In drain casting, a plaster mould draws water from liquid slip; once a wall has formed, the excess slip is poured out. After some drying, workers trim the body with metal tools to the required size and shape. It is then dried thoroughly before biscuit firing. The absorbent biscuit body can receive underglaze painting and glaze before the high firing. This is the maker’s process, rather than a recipe for every Japanese ceramic.

Glaze melts into a thin glassy surface, changing its sheen and reducing penetration by liquids. Underglaze decoration is painted on the body before a transparent glaze is applied and fired; Japanese sometsuke usually uses cobalt for blue designs. Overglaze enamels are painted on an already fired glaze and fixed in a lower-temperature firing. Incising, stamping, applied clay and contrasting slips offer other ways to decorate the surface.

Temperature is only one part of firing. Oxygen-rich oxidation and oxygen-poor reduction can make metal compounds in glazes develop different colours. Wood ash that lands and melts on a pot can form a natural ash glaze; an applied glaze is prepared and put on the surface before firing. An anagama uses a long chamber on a slope, while a multi-chamber climbing kiln links successive chambers uphill.

Iron in a glaze develops celadon’s blue or blue-green colour during reduction firing. A 2001 Shigaraki Ceramic Research Institute bulletin compares test tiles made with the same crackled celadon glaze. Starting reduction earlier produced a bluer sample; later starts brought greener or blackened results. Reading a ceramic surface therefore means considering the glaze formula and firing conditions together, as well as its colourants.

Ceramic production in the Japanese archipelago began with Jōmon earthenware, followed by Yayoi pottery and the Haji ware and haniwa of the Kofun period. In the fifth century, techniques from the Korean peninsula enabled high-temperature reduction firing of Sue ware. Low-fired lead-glazed wares appeared in the Asuka and Nara periods; in the ninth century, the Sanage kilns produced high-fired wares with deliberately applied ash glaze.

From the late Heian period, Tokoname, Echizen, Shigaraki, Tamba and Bizen produced large quantities of hard, unglazed wares for storage and other daily needs. During the Kamakura and Muromachi periods, Seto and Mino also made glazed wares inspired by Chinese ceramics. Unglazed jars and glazed bowls or bottles belonged to overlapping but varied markets and uses.

From the late Muromachi through Momoyama periods, tea practice raised the standing of locally made pottery, including Raku, Shino and Oribe. The Mino Shino tea bowl Hashihime dates to the sixteenth–seventeenth centuries. Its irregular oval mouth and substantial body frame designs of a bridge and thatched hut visible through the white glaze. Form, surface and the act of holding a tea bowl meet in this particular object.

During Toyotomi Hideyoshi’s invasions of Korea in the late sixteenth century, Hizen lords brought Korean potters to Japan. Their skills became one foundation of the region’s ceramic industry. In the 1610s, the Arita area began producing Japan’s first porcelain. Products shipped through Imari were also called Imari ware. Early blue-and-white wares drew on Chinese models, followed by overglaze enamels and a range of styles.

From the mid-seventeenth century, Hizen porcelain entered export markets in quantity. Kakiemon-style wares combined a milky white ground, bright enamels and open compositions; European elites used them for both practical purposes and display. In Kyoto, Nonomura Ninsei and Ogata Kenzan developed decorated pottery, while the Nabeshima domain kiln made presentation wares for the shogunal household. Trade, tea and political gifts created different demands.

After the Meiji Restoration, overseas markets and international exhibitions brought new demand. Nagoya firms obtained undecorated bodies from Seto and Mino, decorated them and arranged exports. Improved transport and clustered workshops expanded this network. In 1904, Nippon Toki, later Noritake, established a large factory in Nagoya using modern European production methods. Regional supply chains and integrated factories offered different ways to organise ceramic manufacture.

In 1925, Yanagi Sōetsu, Hamada Shōji and Kawai Kanjirō used mingei to name the popular crafts made by anonymous artisans, drawing attention to the beauty of everyday things. The Japan Folk Crafts Museum, opened in 1936, became a base for collecting, research and exhibitions. Utilitarian pottery gained a new setting for appreciation and collection, with practising potters also joining the movement.

Hamada Shōji’s 1949 teapot with divided glazes and finger-drawn decoration has an overhead handle, lid and side spout: its form still serves lifting and pouring. Contrasting glaze areas and curved finger-drawn marks articulate the body. A named potter’s tea vessel connects with mingei’s interest in everyday objects; the movement’s participants did not all make anonymous work. Collector Horio Mikio, who owned this piece, collected Hamada’s work with everyday use in mind.

During the war, metals such as iron were prioritised for military production, and ceramics served as substitutes for other materials. From 1941, ceramics had to carry producer identification numbers under a control system that also managed product types and quantities. Substitute goods and controlled wares exhibited by Tajimi’s Mino Ceramic Art Museum document this wartime change in production and daily life.

A ceramic yutanpo is a hot-water bottle for warming bedding. The Shiga Prefectural Peace Museum lists one among substitutes made during wartime metal shortages. Kitanagoya’s history museum explains a detail of the form: corrugations in metal hot-water bottles accommodated expansion and contraction, and ceramic versions copied them. Changing the material could preserve an earlier shape. This wartime use does not establish that ceramic hot-water bottles were first invented during the war.

Postwar expansion in Mino involved different firing equipment at different scales. A 2024 study examined producers that remained in business as demand declined. Among them, larger producers pursued mechanisation and IT for efficient, varied mass production, while smaller producers used their skills and equipment for higher-value goods or varied small batches.

Sōdeisha, founded in Kyoto in 1948, promoted ceramic works that did not need to function as containers. Yagi Kazuo’s Mr Samsa’s Walk of 1954 assembles hollow tubular forms into a ring. Its openings create a sculptural structure rather than a pot for pouring water or serving tea. Such works added a non-functional direction to postwar ceramics alongside utilitarian vessels. From the mid-1960s, exhibitions including an international exhibition of contemporary ceramics in 1964 introduced overseas developments to Japan. Kyoto’s National Museum of Modern Art describes this widening context as gradually changing Sōdeisha’s relative position as an avant-garde group.