Ru ware

Lean close to the glass and look at the surface of the glaze. It is not quite blue and not quite green. It is a soft, misty colour, like a pale sky behind thin cloud. Under that colour runs a fine web of cracks, light as frost on a window. This is Ru ware, and you are in the city that gave it its name.

Ru ware is the pottery of a single place and a short moment. The name comes from Ruzhou, the old prefecture here in Henan province, in central China. During the Northern Song dynasty, kilns in this area made ceramics for the imperial court. The Song dynasty ruled China from the tenth century to the thirteenth century, and its northern capital stood at Kaifeng, not far to the east of here.

The imperial production of Ru ware lasted only a few decades, around the late eleventh and early twelfth centuries. Then the north fell to invaders, the court fled south, and the kilns went quiet. That short life is one reason the ware became so precious. Chinese connoisseurs later counted Ru among the Five Great Kilns of the Song, together with Guan, Ge, Jun and Ding wares. Many of them placed Ru at the very top.

Here is the first surprise. Fewer than one hundred pieces of Ru ware are known to survive anywhere in the world. Most of them sit in a handful of great collections: the Palace Museum in Beijing, the National Palace Museum in Taipei, and the Percival David collection at the British Museum in London. So if you see an original piece here, you are looking at one of a very small family of objects.

Now look at the shapes. Ru ware is quiet and plain. You see shallow dishes, small bowls, narrow-necked bottles, and low round basins that scholars call brush washers. There is very little decoration. No painted flowers, no dragons, no gold. The whole beauty rests on three things: the form, the colour of the glaze, and the way light sits inside it.

That glaze is thick and soft, almost like jade or wax. Its colour is often described in Chinese as sky blue, and in English as duck-egg blue. A popular saying links this colour to the sky after rain clears. The phrase is often repeated in stories about Song porcelain, but it is a poetic tradition, not a documented order from any emperor. Still, stand in front of a good piece and the comparison feels natural.

Then there is the crackle. As the pot cooled after firing, the glaze shrank at a different rate from the clay underneath. Fine cracks opened across the surface. Potters in many places tried to avoid this. In Ru ware, the crackle became part of the look. Collectors admired it, and some later potters copied it on purpose.

Here is the second surprise, and it is on the bottom of the pot. Ru pieces were often glazed all over, even underneath. To fire them, potters rested each piece on tiny clay supports called spurs. When the pot came out of the kiln, the spurs left very small marks on the base. People often compare them to sesame seeds. If a display shows the underside of a dish, look for three or five of these tiny pale dots.

There is a local tradition about the glaze too. According to an old story, the potters here mixed crushed agate into their glaze, which gave it its soft, jewel-like depth. Agate is a semi-precious stone. Historians still discuss how much truth this story holds. Treat it as a much-loved legend, but remember it next time you see that cloudy blue.

For centuries, nobody knew exactly where the kilns had stood. The answer came in the 1980s. Archaeologists identified the main kiln site at Qingliangsi, a village in Baofeng County, in the Ruzhou area. Excavations there found fragments of glazed ware, kiln furniture and the remains of the kilns themselves. Broken pieces, thrown away by potters nine hundred years ago, finally gave the ware a confirmed home.

Ru ware never lost its fame. Later emperors treasured it. The Qianlong emperor of the Qing dynasty, who ruled in the eighteenth century, had his own poems carved into the bases of some Ru pieces in the palace collection. In modern times, the ware still sets records. In 2017, a small Ru brush washer sold at auction in Hong Kong for a record price for Song ceramics.

Today, Ruzhou has not let the craft disappear. Workshops in the city make new Ru-style porcelain, chasing the old colours and the old crackle. You may see studios, shop windows and market stalls filled with these modern pieces. They are not Song treasures, of course. But they show a living craft, and many local potters spend years learning how a single glaze behaves in the fire.

If you visit a workshop, watch how the glaze looks before firing. It is dull and chalky, nothing like the finished colour. Only the heat of the kiln turns it smooth and blue. This is why Ru potters speak of the kiln with respect. A small change in temperature or air can turn a piece grey, green or yellow. Every firing carries some risk.

So take one more moment with the piece in front of you. Follow the line of its rim. Look for the fine cracks and the soft depth of the colour. Notice how little the potter added, and how much remains. When you walk back out into the streets of Ruzhou, you may start to see that pale sky colour everywhere.