Bizen Ware: When the Packing Material Became the Decoration

Nearly every pottery town in Japan is known for something it puts on the pot. Arita has cobalt under a clear glaze. Kutani has five colours over it. Kyoto has enamel and gold. Bizen has nothing at all: no glaze, no slip, no pigment, no brushwork. The pot goes into the kiln the colour of mud and comes out however the fire decided.

And yet a shelf of Bizen is one of the most visually various things in Japanese ceramics — scarlet ribbons, pale round patches, drifts of glassy green, whole faces gone blue-black. None of it was applied. All of it happened in the kiln, and most of it started out as a way of stopping pots from sticking to each other.

Clay from under the rice fields

The material comes from an unlikely place. The best Bizen clay, called hiyose, is dug from beneath paddy fields in the Imbe area of Bizen City — a layer sitting roughly three to five metres down, under the rice. It is sticky and very fine, heavy in iron, and its resistance to heat is low, which for most purposes would be a defect.

It cannot be used as it comes up. The dug clay is left out in the weather for a year or two, then levigated — slurried in water so the particle sizes separate — and then aged. Only after that does anyone throw it.

That long preparation is not fussiness. In a glazed tradition, the clay body is a substrate; the surface is where the work goes. In Bizen there is no surface but the clay, so the clay is the work. Potters here talk about tsuchi-aji — the flavour of the earth — and mean it as the thing being judged.

Two weeks of fire

Bizen is yakishime: fired hard, unglazed, until the body vitrifies on its own. Firing runs somewhere between one and two weeks. The national crafts body puts the standard at roughly two weeks at around 1,230°C in a climbing kiln fuelled with red pine, with wood fed in around the clock; individual kilns vary, and temperatures of 1,200 to 1,300°C are commonly quoted.

What comes out is dense and unusually tough. The old line in Okayama is that Bizen won’t break if you throw it — a proverb rather than a warranty, but it points at something real. Medieval Bizen made the heavy, working end of the pottery trade: storage jars, large water jars, and the ribbed grinding bowls called suribachi. They went out by water — down the Yoshii River in the earlier medieval centuries, later out of Katakami Bay into the Seto Inland Sea — and by the late Muromachi period Bizen was turning up across western Japan. Heavy unglazed pots travel well.

The kilns grew with the trade. Early ones ran about ten metres; by the mid-Kamakura period they had stretched to twenty and thirty, and one Muromachi-period kiln measured some forty metres long and over three metres wide.

The four accidents

Load a kiln that big for two weeks and the pieces are not sitting in neutral air. They are packed against each other, against ash, against the wall — and each of those positions leaves its own mark. Bizen’s four best-known kiln effects, its yōhen, are those four positions, given names.

Hidasuki (緋襷), “scarlet sash,” is the famous one: bright red-orange lines crossing a pale body. When pieces were stacked for firing, rice straw was laid between them so they would not fuse. The straw burns; its alkali reacts with the iron in the clay; where it lay, the clay turns scarlet. It was packing material. Now potters wrap the straw deliberately and place the piece where the flame can’t reach it directly.

Botamochi (牡丹餅), “rice cake,” is a pale disc on an otherwise dark surface — the shadow left where a smaller piece, a cup or a spacer, sat on top during the firing and shielded that patch from ash and flame. Also originally a stacking trick. Also now done on purpose.

Goma (胡麻), “sesame,” is pine ash landing on a piece near the firebox and melting into a spatter — sometimes a scatter of specks, sometimes running into a glassy green pool. This is glaze, in the strict chemical sense. Nobody applied it.

Sangiri (桟切), the blue-grey and blackish-brown zone, comes from pieces buried in ash and charcoal, where oxygen runs short and the iron in the clay reduces to a different colour entirely.

Which is why the single most consequential thing a Bizen potter does is not throwing. It is kamazume — loading the kiln. Deciding what goes where, wrapped in what, buried in what, at what height, in which chamber, is the act of design. Then the kiln is sealed and it is out of anyone’s hands for two weeks. No two pieces come out the same, and the potter cannot fully specify any of them.

A thousand years, and a near miss

The lineage runs back through sueki, the unglazed grey stoneware of the Kofun period, and the local trade got going in earnest at the end of the Heian period around the foot of Mt. Kumayama. By the mid-Kamakura period the reddish-brown body we would recognise had arrived; by the Muromachi period, production had concentrated at Imbe and gone industrial.

Then tea found it. From the late Muromachi period onward the tea masters took to Bizen’s plainness — a tradition that already looked much the way wabi aesthetics were arguing pottery should look — and the Momoyama period was its height, with Toyotomi Hideyoshi among its admirers. In the Edo period the domain lord Ikeda Mitsumasa put the trade on a formal footing, supplying the Imbe kilns with fuel and raw material and appointing the best potters as official domain craftsmen. Six families — Ōae, Kaneshige, Kimura, Terami, Tongū and Mori — held the trade and ran the shared kilns among them. In 1831 the first multi-chambered climbing kilns arrived, and stayed in use until around 1940.

And then Bizen nearly died. Porcelain was cheaper, whiter, lighter and easier to decorate, and against it a brown unglazed pot with an accidental surface looked like something from the previous century, which it was. Through the Meiji era and into the early Shōwa, the trade contracted badly.

The man who reverse-engineered his own tradition

Kaneshige Tōyō (1896–1967) was born in Imbe, into the Kaneshige family — one of the six. What he did from around 1930 was archaeological as much as artistic: he studied surviving Momoyama Bizen and worked backwards from it, rebuilding the loading and firing methods that produced those surfaces, including the straw-wrapping that gives hidasuki. By the early 1940s he had recovered the range of old Bizen effects. In 1956 he was designated a holder of Important Intangible Cultural Property — a Living National Treasure — the first Bizen potter to be so named. Fujiwara Kei (1899–1983) and Yamamoto Tōshū (1906–1994) followed.

Bizen ware was designated a national Traditional Craft on 1 November 1982; the recognised production area covers Bizen City, Okayama City and Setouchi City. In 2017 it was named a Japan Heritage site as one of the Six Ancient Kilns. Imbe today is a working pottery town, most of its kilns and shops within walking distance of the station.

Living with a Bizen pot

Because there is no glaze, the rules are a little different from ordinary tableware — and pleasantly simple.

Wash it before the first use with mild dish soap; fine clay and ash can still be sitting on the surface.

Wet it before you use it. The potters’ own cooperative in Okayama recommends dipping the piece in water and blotting it with a towel before serving — the colours come up noticeably, and a damp body takes on less oil and odour.

Dry it properly. This is the one that actually matters. Unglazed stoneware left damp will smell, and can grow mould. Wash promptly, dry completely, and don’t stack it away wet.

No direct flame and no oven. Bizen is not flameware — for that, see Iga. Sudden temperature swings can crack it. If you want warm sake, heat it elsewhere and pour it into the tokkuri.

Microwave and dishwasher: ask the maker. The Okayama Bizen potters’ cooperative says both are generally fine but that it depends on the individual piece — which is an honest answer for a ware where every piece came out of the kiln differently. Hand washing is the safe default, and a lot of retailers advise it flatly.

Mind the underside. An unglazed foot is rough enough to scratch a lacquered or polished table. A cloth mat solves it. The rough feel of the pot itself wears smooth with use.

You will also hear, in Bizen shops, that beer poured into an unglazed cup throws a finer, longer-lasting head, and that cut flowers last longer in a Bizen vase. The proposed mechanism — a microscopically irregular, minutely porous surface — is at least plausible, and the claims are repeated everywhere in Okayama. Treat them as a pleasant possibility rather than a reason to buy. The reason to buy is that you are getting a two-week fire on a shelf, and no one, including the person who made it, knew quite how it would come out.

Read: Japanese ceramics for every day, or choosing sake cups. Or browse hand-picked, Japan-shipped ceramics on The Table.

Sources & Further Reading

• BIZEN Yaki (Pottery) — Traditional Crafts Aoyama Square — The national traditional-crafts body: the 1 November 1982 designation, the Bizen / Okayama / Setouchi production area, hiyose clay, firing at about 1,230°C for roughly two weeks on red pine, and the Living National Treasures.
• Bizen Ware — The Six Ancient Kilns (Japan Heritage Promotion Council) — The Japan Heritage council on the Heian-period start near Mt. Kumayama, the growth of the kilns from ten to forty metres, Ikeda Mitsumasa’s Edo-period patronage, and the multi-chambered climbing kilns of 1831.
• About Bizen Ware / How to Use Bizen Ware — Okayama Bizen Ware Potters’ Cooperative — The production association itself, in Japanese: the six Edo-period kiln families, the hidasuki straw reaction, Kaneshige Tōyō’s 1956 Living National Treasure designation, and the care and usage guidance followed above.
• What is Bizen Pottery? — Okayama Prefecture Official Tourism Guide — The prefecture on firing temperatures, the goma / sangiri / hidasuki kiln effects, the 2017 Japan Heritage listing, and the Imbe district today.