Turn It Over: Reading a Vessel from the Underside

We tend to look only at the surface of a vessel—the rim that meets our lips, the glaze that catches the light, the delicate painted design. Our eyes stop there. Yet every vessel has another side.

Face down on a table, tucked away at the back of a shelf, the underside spends its life unseen. This is where the potter left bare clay, pressed tools into the surface, accepted the marks of fire, and sometimes even carved a name. Yet this hidden side often reveals more than the front about where a piece was made, when it was made, and by whose hand.

Turn a vessel over, and you see it differently. Here, we trace the act of “looking at the underside” through four clues. By the time you finish reading, you may find yourself flipping over whatever vessel sits closest to you.

Tsuchimise: Where You Meet the Clay Itself

Most glazed vessels leave some part of the base unglazed. Because glaze melts into glass during firing, a fully glazed bottom would fuse to the kiln shelf. So the potter wipes or trims the glaze away from the base before the piece enters the fire.

Yet the term tsuchimise—literally “showing the clay”—refers to more than just this necessary patch of bareness. It names the deliberate choice to leave clay exposed as a point of beauty: not clay that happens to be bare, but clay the potter chose to reveal.

This intention is easiest to see in Raku ware, the Kyoto tradition dating to the Momoyama period (1573–1603 CE). The founder, Chojiro, covered his tea bowls entirely with glaze—a style called soyu, or “full glaze.” His successor, Jokei, influenced by Oribe taste, became the first Raku potter to leave the clay exposed. By the third generation, Donyu was alternating between full glaze and exposed clay, bowl by bowl. To conceal the clay or to reveal it was not a technical limitation but an aesthetic choice.

Showing the clay serves another purpose. By leaving part of the body unglazed, the contrast sharpens between the glassy gleam of the glaze and the dry grain of bare earth. Gloss and matte, color and clay, light and shadow. Set side by side, the glaze looks deeper and the clay more vivid. Tsuchimise is a kind of negative space that heightens the dialogue between surface and body.

On Shino ware, the unglazed foot has long been treasured as a point to admire—a place to savor the beauty of the clay itself. Above, a soft pink-white glaze; below, a pale brown the color of orange earth. A single bowl holds both its glaze and the clay that gave rise to it, each making the other more vivid.

Kodai: Where the Hand and Tools Remain

At the center of the exposed clay sits a small ring that supports the vessel. This is the foot ring—kodai.

Foot rings are made in two main ways. In the first, the potter throws the form on the wheel, then carves the foot from the leather-hard base with a trimming tool. In the second, a separately shaped ring is attached to the bottom. When carving, potters usually hollow out the inside of the ring. If shaping the upper body is a process of building up, the foot is a process of carving away. That is why the marks of the blade—the rhythm of the trimming—survive here more vividly than anywhere else.

And here lies the heart of looking at the underside. Precisely because the foot is hidden, it preserves the potter’s habits: the country, the era, the kiln, the particular hand of an individual potter. For this reason, the foot has long been considered one of the most reliable clues for authenticating a piece and identifying where it was made.

By the Momoyama period (1573–1603 CE), potters were devoting special care to this hidden area, and the practice of turning vessels over to appreciate the foot took root as a recognized custom. Looking at the underside is a way of seeing that has been part of Japanese ceramic culture for centuries.

Feet take many forms. A simple ring is called wa-kodai. A stepped ring resembling a bamboo node is takefushi-kodai. A foot with a ring of glaze wiped away inside it is janome-kodai, or “snake-eye foot.” A ring with notches cut into it is wari-kodai, or “split foot.”

Each shape carries its maker’s intention and style, and the way a foot is carved changes how a vessel sits and how it holds itself.

A soba choko cup from the Baizan kiln of Tobe ware, featuring a janome (snake’s-eye) foot ring. The glaze is left only on the further-recessed inner portion of the foot ring, and a meiin (maker’s seal) reading “bai” (梅, plum)—described later—is stamped there as well. This shows that even an everyday item like a soba choko carries a meticulous attention to detail down to the smallest features.

The foot of this Iga ware kobachi is what potters call a tokin-kodai. Look closely, and a small peak rises at the center of the foot ring—shaped, as the name suggests, like the pointed headgear known as a tokin.

Meato: Marks Left by Fire and Time

Inside the foot ring or on the inner base, you sometimes find small dots arranged in a circle—often three to five. These are meato, or spur marks: the scars left by firing.

They come from a practice called stacking. To make the most of limited kiln space, potters set vessels one on top of another, separated by small supports. Where a support touched the glaze, the glaze could not fuse, and a bare spot—a dot—remained. These supports took various forms, such as small clay pellets, grains of sand, or refractory clay spurs.

These marks are not unique to Japan. The technique of stacking for efficient firing was shared across East Asia. The same scars appear on the bases of qingbai—a pale, bluish-white porcelain—from the Northern Song dynasty (960–1127 CE) Jingdezhen kilns, on wares from the Korean peninsula, and on ceramics produced in large quantities in Vietnamese and Thai kilns and shipped across the sea. The small dots on the underside reflect firing techniques shared across East Asia, whose ceramics also moved widely through maritime trade.

Because the arrangement and material of the supports varied by kiln and period, spur marks help identify which lineage of kilns produced a piece and when it was fired. These small dots are, in effect, the vessel's fingerprints, recording how it passed through the fire.

At first glance, the marks may look like flaws—chips in the glaze. Yet some potters deliberately leave them as part of the vessel’s landscape. Unlike the uniformity of industrial products, these are traces of fire and time.

Meikan: The Maker’s Mark

At the most hidden spot of all—the very bottom, rarely seen by anyone—a maker sometimes leaves a mark.

A seal, a brushstroke, an incision made with a wooden spatula: when a potter records the name of the artisan, the kiln, or a patron on the base, the mark—or the act itself—is called meikan, a maker’s mark. A stamped version is called meiin. On the bases of Imari ware, for example, you often find a squared character for fuku (福, fortune), known as kaku-fuku; a swirling version called uzu-fuku; auspicious phrases; or even reign marks such as “Made in the Great Ming Chenghua era” (1465–1487 CE)—inscribed in homage to celebrated Chinese kilns rather than to date the piece. These small marks on the bottom record where its maker wished to belong.

This practice is not limited to antiques. Kilns and potters still stamp and sign their work on the underside today: a small seal bearing a kiln’s name, a stamp certifying the place of origin, a mark pressed by hand one piece at a time. In the same place where Imari craftsmen once carved the character for blessing, contemporary artisans leave their own marks. Turn over a piece you have just picked up, and you may well find one—a small inscription telling you what lineage the vessel belongs to.

Most buyers never notice it. Even in daily use, the mark seldom comes into view. Still, the artisan inscribes it, leaving proof that the hand reached all the way to the end, in a place they know will rarely be seen. When you turn a vessel over and find that mark, the maker's hand rises into view on the other side.

The Blue Brush Rim Square Sauce Plate, from Shiga, is the work of Omi Shimoda Toubou—the only kiln still carrying Omi Shimoda ware into the present. On its underside, a woven-cloth texture called nunome, left by the cloth during forming, spreads across the base, and pressed over it is a maker’s mark bearing the kiln’s name. Together with that cloth-marked base, the small mark speaks quietly of a plate like no other.

The World That Opens from the Underside

Clay, hand, fire, name. Layers of traces that never appear on the surface remain on the underside—the clay it was made from, the hand that carved it, the kiln whose flame it passed through, the maker who gave it form. Knowing what lies beneath adds a dimension to the world of vessels; the same piece begins to appear as an object with a history.

Next time you pick up a vessel, turn it over gently. Feel the ring of clay beneath your fingertips, the rhythm of the trimming, the circle of dots, the small inscription. This is a gesture that connoisseurs have practiced for centuries. The underside is not the end of a vessel—it is another entrance.

References: Yabe, Yoshiaki, ed. Kadokawa Nihon Toji Daijiten [Kadokawa Encyclopedia of Japanese Ceramics]. Tokyo: Kadokawa Shoten, 2002.