Seihakuji: White Porcelain Where Blue Pools in the Carving

Seihakuji is porcelain made by covering a white porcelain body with a clear glaze that holds the faintest trace of iron, then firing it to a white tinged with blue.

Flat surfaces look almost entirely white. But where the glaze gathers in a carved groove or in the valley of a relief pattern, a pale aqua settles there and deepens. Blue appears within the white, like a shadow. This is what makes seihakuji worth looking at.

Because the names are so close, it is often confused with celadon and white porcelain. It differs from celadon in the character of the glaze, and from white porcelain in the tint of the glaze. This article separates those differences first, then covers how to choose and use seihakuji pieces.

How it differs from celadon and white porcelain

All three carry the character for porcelain in their names, but there are only two things to look at. What the body is made of, and how much iron is in the glaze.

What separates it from celadon is the glaze

Celadon and seihakuji work the same way: iron in the glaze turns blue in the flame of a reduction firing. What differs is the amount and the thickness.

In celadon, the glaze itself carries the color. An iron-rich glaze is applied thickly, wrapping the whole piece in blue-green. It hides the color of the body, so it works even over an iron-rich stoneware clay.

In seihakuji, the glaze is all but clear. The white body shows through the thin glaze, so flat surfaces read as white. Blue is visible only where the glaze has pooled thickly. It is a treatment that cannot exist without a white body.

What separates it from white porcelain is the tint of the white

White porcelain and seihakuji both use a white porcelain body, and there they are the same. What differs is the tint of the glaze laid over it.

White porcelain keeps the iron in its glaze as low as it can, aiming to show the white of the body as it is. Seihakuji deliberately leaves a trace of iron, layering a blue cast over the white. On the same white ground, seihakuji reads as a cool, clear white depending on how the light falls.

From Jingdezhen in the Northern Song

Seihakuji is held to have been perfected at Jingdezhen in China during the Northern Song dynasty (10th to 12th centuries). In China it was also called yingqing, or shadow blue. The name describes blue settling into the shadow of a carved pattern.

In Japan, the Gifu Prefecture potter Tsukamoto Kaiji was designated a Holder of an Important Intangible Cultural Property, a Living National Treasure, for white porcelain and seihakuji in 1983. Taking Northern Song white porcelain and seihakuji as his model, he pursued thin, sharp carving and a clear glaze.

Blue only appears where there is carving

Almost every seihakuji piece has relief and recess. Without somewhere for the glaze to pool, no blue shows.

• Carving　A pattern is cut into the body with a blade. Angling the blade makes the blue deepen toward the deeper side of the groove
• Shaving　The surface is shaved into facets divided by ridgelines. Glaze pools in the grooves of shinogi as well
• Raising with a mold　A mold lifts the pattern into relief. Blue settles in the valleys around the raised design
• Trailing　Slip is squeezed out to draw a line, the technique called icchin. Glaze pools along both sides of the line

Under the same glaze, the depth and angle of the groove change how deep the blue runs. Seihakuji is a glazing technique and, just as much, a technique for carving the body.

Seihakuji at Nokaze

Maeda Asami (pictured at the top), working in Kyoto, finishes scalloped plates in seihakuji, their floral arabesque raised in relief from a mold. The rim undulates like petals, and in the well the arabesque runs in a ring. Glaze pools around the raised pattern, and the design surfaces within the white like a shadow.

They come as small and medium plates, so you can match sizes within a single pattern. They work as side plates, sweets plates, or saucers for a cup. Her technique is introduced in her artisan profile. The pieces can be seen in the Maeda Asami collection.

She finishes the same pattern in a haisei glaze as well. It is a colored glaze whose name carries the character for ash, laying a pale blue-green over the white. How glazes made with ash differ is covered in the ash glaze article.

Using seihakuji

Because the body is porcelain, it is among the easiest ware to look after.

• No seasoning needed　It does not absorb water, so you can wash it and use it straight away
• Stains and odors rarely linger　Oily food and strongly colored dishes are fine
• Use a soft sponge on the relief　Wipe gently with a sponge so grime does not stay in the grooves of the pattern

Being white, it suits whatever you serve on it. But seihakuji only works when the pattern shows. Rather than covering the whole surface with food, place a little at the center and leave the relief around it visible. Even a single piece of wagashi or fruit is enough for the blue to do its work.

Day-to-day care for porcelain is covered in caring for Japanese ceramics. If you would rather know first how it differs from stoneware, do have a look at stoneware and porcelain

Related articles and terms

White and blue porcelain

• Celadon (Seiji): The Blue-Green Glaze of Iron and Fire
• Japanese Porcelain: Made from Stone, Not Clay
• Sometsuke: Blue and White Porcelain, Explained
• Ash Glaze (Haiyu): The Origin of High-Fired Japanese Glazes
• Japanese Pottery Glazes: The Main Types Explained

Techniques that create relief

• Shinogi: The Carved Ridges on Japanese Pottery
• Icchin: Slip Trailing, the Raised Dot Technique
• Artisan Maeda Asami | Japanese Porcelain Patterned in Relief, Not Paint

Read further

• Stoneware vs Porcelain: How to Tell Them Apart
• A Short History of Japanese Ceramics, Jomon to Now
• How to Care for Japanese Ceramics: A Practical Guide

Pieces available at Nokaze

• Arita Porcelain | Hand-Painted Japanese White Porcelain