Shizen-yu
Shizen-yu is a glaze that forms naturally — no glaze is applied by hand. During long wood-firing, ash from the burning firewood swirls through the kiln, settles on the clay, and melts at high temperature into a glassy surface. Its color ranges from olive green to amber, growing darker where ash falls thickly. Shizen-yu is the defining beauty of Bizen, Iga, Shigaraki, Echizen, and Tamba japanese pottery, and no two pieces are ever alike.
FAQ about Shizen-yu
Q1.How is shizen-yu different from an applied glaze?
Natural ash glaze (Shizen-yu) is formed without applying any liquid glaze; instead, firewood ash melts inside the kiln to create a natural coating. Because of this, no two patterns are ever identical, making every piece one of a kind. In contrast, artificial glazes are applied by dipping or pouring to achieve intentional colors and a uniform finish.
The greatest charm of natural ash glaze lies in its unpredictable expressions, brought to life by the accidental interplay of fire and ash that even the potter cannot foresee. It offers a warm, rustic texture that celebrates the natural feel of clay, along with a subtle patina that deepens with use over time. It brings a powerful yet refined, once-in-a-lifetime beauty—as if the energy of nature itself resides in the vessel—into your everyday life.
Q2. Is shizen-yu ware safe for everyday food use?
Here's my take:
Yes. Because these pieces are high-fired and the melted ash forms a natural glassy layer, they are perfectly suitable for everyday use. For vessels that retain some absorbency, performing a process called "medome" (sealing) before first use will give you extra peace of mind.
"Medome" is a care step where you boil newly purchased pottery in rice water (or water with starch) to fill the microscopic pores and invisible hairline cracks (crazing) on the surface.
As the starch from the rice seals these tiny gaps, it prevents tea, food oils, and odors from soaking into the vessel, while also helping to suppress mold and stain buildup. It is an essential step to keep your favorite tableware clean and enjoyed for years to come.
For more details on caring for Japanese tableware, please refer to the section below.