Tenmoku glaze sake cup by Okada Yu

Width: 8.3cm Height: 4.9cm

Tenmoku glaze sake cup

- Created by Masaru Okada -

Work summary

This Tenmoku-glazed sake cup was created by Okada Masaru, who runs a kiln in Uji Sumiyama, Kyoto. The soft curves that flow from the gently open rim to the base, and the misty silver light that appears on the matte black glaze with a pale purple-gray hue, create a tranquil yet somehow warm appearance.

Characteristics of the design

Rim : The edge is slightly curved outwards but rounded, so it gently touches the lips. The rim is slightly tinted with red, evoking the image of Beni Tenmoku.

Body : Based on a hemispherical shape, the surface is gently pressed down with the pads of the fingers after being shaped on the potter's wheel, creating a subtle undulation. This enriches the shadows in the glaze, creating a different appearance depending on the angle from which it is viewed.

Base : A low, narrow base. The sides of the base are lightly planed, providing stability and a comfortable grip when placing the sake cup.

Glaze and Technique

Tenmoku glaze color : After firing the iron-rich feldspar glaze with a reducing flame, a short oxidizing flame is applied at the end of the firing process, creating a gradation of purple-gray to silver-gray to blue-ink on a black background. The glaze surface is semi-glossy and has a texture that feels like it sticks to your fingertips.

Silver Haze : Fine iron crystals float in the matte finish, creating a pale silver veil. Under strong spotlight, the crystals shine like a nebula, evoking a tranquil cosmic view.

Clay and reduction : Mr. Okada mixes clay from around the coal mine with fine clay from Seto, adjusting the balance between plasticity and firing strength. The stable clay body is resistant to distortion even when subjected to strong reduction, supporting this delicate glaze.

Historical background

Tenmoku glaze originates from the black-glazed bowls of the Jian Kiln in Fujian Province during the Song dynasty, and is said to have been introduced to Japan by Zen monks during the Kamakura period. Among them, the purple-tinged "Konoha Tenmoku" and "Haika Tenmoku" are rare, and were considered to be precious landscapes that only came about through the chance of an oxidation-reduction balance within the kiln. This work can be said to be the result of an attempt to control this chance and reliably reproduce it using modern technology.

Aesthetic Intention and Spirituality

This sake cup, wrapped in a veil of purple gray, combines the serenity of the Zen concept of "emptiness" with the sparkle of a once-in-a-lifetime encounter brought about by the kiln transformation. When sake is poured into it, a faint light floats on the surface, evoking the pale purple sky before dawn and leaving the drinker with a deep, lingering aftertaste.

How to use and points to note

Suitable for room temperature to slightly warm sake : The matte glaze keeps the sake at a gentle temperature, allowing the aroma to develop gradually.

Light source selection : The silver haze emerges under the warm light of incandescent lamps or candles, while the purple-gray gradation stands out under daylight LEDs. Enjoy the completely different expressions depending on the time of day and lighting.

Also suitable as a tea bowl : the inside is slightly raised, making it more suitable for thin tea and gyokuro tea than thick tea. The green of the tea stands out against the black glaze.

This sake cup, with a silver mist floating in the purple ash, is a masterpiece that demonstrates the kiln change control techniques that Okada Masaru has cultivated over many years. Sipping a cup while gazing at the infinite universe hidden in the silence will add a quiet elegance to your everyday life.