The Blue That Sailed Both Ways

The order comes down the river with the rice boats. A man named Zhang Wenjin, from Jintang in Yushan county, wants an incense burner and a pair of flower vases to give to a temple. He is not a prince. He is an ordinary devout man, and he wants his name on them — and the date, and the reason.

The reason is fear. He asks for "the protection of the whole family, and for peace and prosperity of his descendants." It is 1351. Within weeks of this dedication, the Yellow River works will spit out tens of thousands of angry conscripted labourers, the Red Turban revolt will begin, and the Mongol Yuan dynasty will start to come apart. Zhang Wenjin cannot know that. He only knows that the world feels thin, and that porcelain lasts.

He is right about the porcelain. Six hundred and seventy-five years from this morning, the two vases you are about to paint will be standing in a glass case in London, in a museum, and every art history student on Earth will know them by a name he never heard: the David Vases. They are the earliest blue-and-white porcelain in the world that carries its own date.

Your job today is the blue. Roll up your sleeves.

Nobody in Jingdezhen makes a pot. The town makes the pot. A Ming encyclopaedia of 1637, Song Yingxing's Tiangong Kaiwu, counted the stages and wrote a line that has followed Chinese ceramics ever since.

"For the total labour in a single cup, it passes through seventy-two hands, and only then can it become a vessel." 共计一坯之力，过手七十二，方克成器 — 宋应星《天工开物》, 1637

Follow one lump of the white earth through the shop. Tap a stage — watch what happens to it, and watch the hands add up.

Here is the strangest thing about your job. The colour in your bowl is not blue. It is a dull greyish-black sludge, like wet ash. You will paint an entire masterpiece in a colour you cannot see, and only the fire will tell you what you actually did.

The powder is cobalt ore, roasted and ground. Two kinds reach the town. One is dug in China and is heavy in manganese — cheap, and it fires a soft greyish-violet. The other travels the Mongol roads from Persia, from the mines around Kashan and Qamsar, and is heavy in iron and almost free of manganese. That one fires a deep sapphire — and because iron collects where the brush sat longest, it leaves little near-black pools the collectors call "heaping and piling." Get your recipe wrong and the fire will publish your mistake forever.

In the painting shed nobody paints a whole vase either. One hand draws the outline of every flower — gouxian, the drawn line — and passes it on; the next fills the shapes with washes of thinned blue — fenshui, dividing the water. A third does nothing all day but the rings around the foot. Speed comes from never changing task.

You have the whole vase to yourself. Choose a band, choose a motif, and put it on. Then glaze it, and find out what you did.

Your vase goes into a saggar — a rough clay box that keeps the ash off — and the saggars are stacked into a kiln the size of a house. Then the pine goes in. Porcelain needs about 1300°C, hotter than a lava flow, and the fireman has no thermometer: he reads the colour of the light and the way a test-piece pulled from a spy-hole snaps.

He also controls the air. Choke the vents and the flame goes hungry — a reducing fire, which strips oxygen back out of the iron in the clay and leaves the body a clean blue-white. Let too much air in and that same iron turns the porcelain a straw-yellow and dulls your blue. One vent, two completely different pots.

Here is a drawing of what Zhang Wenjin actually received — one of the pair, 63.6 cm tall, built up in stacked bands like a page of writing. Nothing on it is decoration for its own sake. Tap each band.

This is the part that makes the vase more than a vase. The cobalt is Persian. The shape and the crowded banded design are what Persian and Arab buyers liked. The clay and the fire are Chinese. The ore came east; the finished pots went west — and the biggest hoards of Chinese porcelain on Earth ended up in Istanbul and in a shrine in north-west Iran.