Interesting information.

Chinese porcelain was a discovery through the many years of development and manufacture of the pot making techniques specific to China.  Three conditions made it possible for the emergence of porcelain:

• The use of stone containing rich sericite elements, or Porcelain Clay  as the raw material for the body of the ceramic  pot
• The ability to increase of the temperature of the potters kilns to a temperature of 1300 degrees that included designing special  building techniques which supported the  kiln
• and finally, the development of the wood-ash glaze.

These three conditions developed in the Yuyao region of Zhejiang towards the end of Eastern Han Dynasty from A.D.113 to 175. Wood-ash glaze could be coated on the body at high-temperature, making the pot look bluish green or yellowish green. This initial porcelain colour was a high-temperature glazed celadon ware. Called "Yuezhou Celadon", this was the colour that identified Chinese porcelain.

Chai (yao) Kiln

One of the well known ancient kilns, Chaiyao Kiln was known as the royal kiln for Emperor Zhou Shizong, Later Zhou of Five Dynasties, whose family name was Chai after which the kiln was named.  Despite searching, the sites of Chaiyao Kiln remain undiscovered, but are thought to be around Zhenngzhou, Henan Province.

According to historical records, this special porcelain ware produced by the Chaiyao Kiln and,  "featured smooth, delicate outlook with fine cracks on sky blue glaze; most of the products were with foot showing the color of coarse yellow earth."

An important book written in Ming Dynasty called Sacrificial Ding & Li in Xuande Reign,  put Chaiyao ware as the top quality porcelain all collections in the imperial court collections.  It is said that very few Chaiyao products still exist in the world, and thus there is a common saying that, "It takes ten thousand pieces of gold to have a piece of Chaiyao ware." However the following article also sheds a different light on the meaning if this phrase. However, it is indeed impossible to authenticate a Chaiyao ware because no sites of the kiln have been so far discovered or excavated. A stoneware pillow in the Sir Percival David Collection bears an incised poem by the emperor Ch'ien Lung calling it Chai ware, but it is virtually indistinguishable from ChÄn.

An 18th c. commentator wrote that its colour was 'blue as heaven after rain seen through a rift in the clouds'. Indeed it was known as Celeste Glaze which also means heaven.

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This was translated by my friend Hans Qin. It refers to the type and style of porcelain described above. I thought it was very beautifully written and wished to share this with you.

A Single Piece Worth a Thousand of Pieces of Gold

Published by 'China Relics Gazette'
Written by Li Longjiang

"No other porcelain will interest you any more after you
have appreciated the Chai Kiln porcelain; a single piece
of Chai Kiln porcelain is worth  a thousand pieces of gold. "
Only after you have looked at  Chai Kiln porcelain can you
comprehend that  "worth a thousand pieces of gold " in this
old saying, handed down over one thousand years, literally
means it contains a thousand pieces of gold.

The lotus-leaf-shaped bowl which I got hold of many years
ago is jet-black and shiny with glaze. It gives out the blue light .
Slightly change its angle and you will see it changes to
grape-purple and tens of  thousands of golden rays from the
tens of  thousands of  gold pieces in the porcelain are blinding.
It can only be appreciated under soft light. The camera can hardly
capture its true feature. The brim is lined with pieces of gold and
the glaze has peeled off. Your first sight of it will always remain in
your memory. Many of my friends exclaimed "Chai Kiln porcelain
is extraordinarily beautiful."

The porcelain glazed with many pieces of gold could only be used
by the royal family. That's why it's seldom seen. Even if it's seen,
the kiln workers had no way to find so much gold to imitate it. It's very
natural that the art was lost.

It was rumoured that Chai Kiln porcelain was made during the time
of Chai Shizong, Emperor of  Later Zhou of Five Dynasties(954 -
959) and because  his surname was Chai and he ordered the
porcelain to be made, the porcelain was named Chai Kiln porcelain. 
Actually we should understand a simple fact that many emperors in
Chinese history loved porcelain, but none of them named  a kiln with
his own  noble surname. The name of the kiln was only named after
the owner of the kiln or the name of the place.

The Chai Kiln porcelain boasts many colours. More than ten years
ago I saw a porcelain bottle at a collector friend's home which was
glazed brown, gave out the  blue light  and turned  purplish red,
the pieces of gold in the glaze formed tens of thousands of plum
blossoms and sent forth tens of thousands of golden rays,  which
is incredibly beautiful.

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My friend, Craig Coussins, has been collecting antique Chinese Bonsai-Penjing pots for some years. Here are some of his pots. They date from the 17th Century to the 19th Century