Most of the porcelain that left Japan over the last four centuries was made for the open market. Some of it travelled abroad — Imari ware reached Europe through the East India Company's routes; Hasami ware filled ordinary households across Japan for generations. But there is a quieter strand of Japanese porcelain that was made for almost no one at all.
For nearly two hundred years, this refined porcelain was produced in a single hidden valley in the hills of Saga Prefecture. It wasn't sold. It wasn't exported. It was made by a closed group of hand-picked potters whose techniques were guarded behind a checkpoint, for one client only: the Shōgun.
That porcelain is called Nabeshima ware. The valley is called Ōkawachi-yama. And the family at Kosen Kiln has been making it, in one continuous line, for over three hundred years.
Why Nabeshima isn't Arita
You'll hear Nabeshima ware mentioned in the same breath as Arita ware. The two were born within a few miles of each other, in the same Edo decades, both relying on the same Hizen porcelain stone. Visually, they share a vocabulary: white porcelain, fine painting, occasional touches of cobalt blue and red.
The difference is what they were made for.
Arita ware was the open trade. Its kilns produced volume — for daily use in Japanese homes, for the European export markets via the port of Imari, for the wider world's appetite for Eastern porcelain. (Most of what reached Europe under the label "Imari" was actually made in Arita and shipped out from Imari's harbour.)
Nabeshima ware never left the domain. The Nabeshima clan — Saga's ruling family — chose thirty-one of the most skilful potters from Arita, moved them inland into a remote valley, and put them to work making porcelain to give as tribute to the Shōgun and other lords (daimyō). None of it was for sale. The techniques were trade secrets, and a checkpoint at the entrance to the kiln village kept them in.
That arrangement lasted from 1675 until 1871, when the new Meiji government abolished the domain system. Today, the kilns of Ōkawachi-yama work for themselves — but the lineage, the techniques, and in some cases the families are unbroken.
Three Nabeshima styles, and one that's rare
Within the Nabeshima tradition, three principal styles took shape.
Iro-Nabeshima (色鍋島) is the polychrome work — red, yellow, and pale green enamels painted over a fine cobalt-blue outline. The most ornate of the three.
Ai-Nabeshima (藍鍋島) is the blue-and-white sometsuke — the entire decoration drawn in graduated cobalt under the glaze. Quieter than the polychrome work, and more contemplative.
Nabeshima Seiji (鍋島青磁) is celadon — a jade-coloured glaze applied thickly over white porcelain. Of the three, it is the rarest. It depends on a stone that almost nowhere else in Japan still works with at scale: the local celadon mineral, dug from the hills of Ōkawachi-yama itself.
(There are also Sabi-Nabeshima — iron-toned — and Ruri-Nabeshima — a deep ultramarine — but these are narrower expressions. Most kilns work within the three principal styles above.)
Of the thirty or so kilns still working in Ōkawachi-yama today, only about three make celadon as their main range. Kosen Kiln is one of them.
The blue dug from the mountain
The first thing to notice about Nabeshima celadon stone is that it isn't blue. It's a faintly yellow rock. The whole transformation happens in the firing.
The stone is crushed, dissolved in water until it becomes a thick liquid, and brushed in generous layers over a porcelain body. Inside the kiln, it converts into a translucent jade-green glaze with an unusual depth — the colour seeming to sit a millimetre or two below the surface rather than on top of it. (That depth is a quirk of physics: countless tiny air bubbles trapped in the glaze refract the light, giving the celadon tradition the softened, almost watery look it prizes.)
It is also unforgiving work. The glaze has to mate exactly with the porcelain body, or the piece cracks during firing. Layers must be thick — too thin and the colour never emerges — but a thick glaze takes much longer to dry, which limits how much can be made at once. The reject rate is high. Production is slow.
The reason any of this still exists at scale, in this one valley, is partly geology and partly geography. The stone is here. The families who learned to work it are here. The combination has held for three and a half centuries.
The family still making it
Kosen Kiln (虎仙窯) is run by the Kawasoe family. Their connection to Nabeshima porcelain reaches back to the Edo period, when the family worked at the domain kiln as 細工人 (saiku-nin) — specialists in fine modelling and glaze preparation. The trade passed down for the next three centuries.
In 1963, the kiln's then-head, Kawasoe Tameo, turned his attention back to celadon. The technique was still alive, but the wares were expensive, made in small numbers, and rarely seen outside of formal gifting contexts. He spent over a decade refining the glaze. His goal wasn't to recreate something perfect for a small audience; it was to make the glaze consistent enough to produce more of it, so more people could live with celadon as everyday ware.
That work made the Kosen Kiln of today possible. In 2016, the kiln formally rebranded as Nabeshima Kosen Kiln (鍋島虎仙窯), launched a tea-ware series, and introduced "Kosen" as a more accessible contemporary line. The vision they describe for themselves — 鍋島焼文化の確立 — translates roughly as "establishing Nabeshima ware as a living culture". Three centuries of guarded craft, in other words, finally opening their gate.
The Nabeshima Kosen Kiln we carry
We carry a small but considered range of Kosen Kiln's work.
The celadon rice bowl is our favourite as a versatile piece. Sized as a rice bowl, but at home with a soup, a small dessert, or a morning yoghurt. The jade tone is a particular pleasure against the white of rice.
Two teapots: the side-handle teapot — the classic Japanese kyusu shape, sized for careful two-cup pours — and the top-handle teapot for slightly larger volumes. Both in jade glaze.
Tea cups in two finishes: the tea-cup set in jade and the crackle-glaze set, plus a tea-cup-and-saucer pair in crackle glaze for more formal moments. The crackle finish — fine cracks held in the glaze, deliberate rather than accidental — is part of the Nabeshima tradition's quieter visual vocabulary, and pairs well with darker teas.
Two mugs, again in jade and crackle glaze — a more casual version of the cups, sized for everyday use.
And our first piece of sake ware: a celadon sake-cup set of two. A matching sake bottle is on its way.
A small range of celadon plates is also planned for later in the year.
If you're new to celadon, the rice bowl is the easiest first piece. It sits comfortably in the daily rotation, the colour holds well against food, and the jade depth is hard to look away from once it's in your hand.
→ Shop the Nabeshima Kosen Kiln collection
If you'd like to read about the wider region, our guide to Hasami ware covers Nagasaki Prefecture's porcelain tradition — Hasami town sits just over the prefecture border from Ōkawachi-yama.
