In order to prevent the glaze from adhering to the sagger, coarse clay kiln furniture is used to hold up the porcelain when firing it.
At that time, the Yaozhou kiln used a three-legged firing rack, which would leave three dents on the bottom of the porcelain.
The stacking method can save space, but it will inevitably leave traces on the inner bottom of the utensils.
However, the inner wall and outer sole of the secret-color porcelain unearthed from the underground palace of Famen Temple are as smooth as a mirror, without a single flaw.
This level of craftsmanship can only be achieved at Shanglinhu Kiln.
Finally, using a porcelain sagger and sealing it with glaze, the green color of Qianfeng can be presented to us.
If firing porcelain with a sagger is a pioneering work in the history of porcelain, then the method of sealing the seams of the sagger's mouth with glaze is the icing on the cake.
At temperatures higher than the kiln temperature, a large number of iron ions in the porcelain blank are reduced.
This may be one of the reasons why secret color porcelain has better quality!
Someone once tested and compared the composition of secret color porcelain and ordinary celadon.
Data shows that the reduced iron ions in secret color porcelain are ten times that of ordinary celadon.
The high temperature in the completely enclosed space created the emerald color of Qianfeng, which was just a little bit greenish-yellow glaze.
There are two green and yellow bowls in the "Clothing Tent" discovered in the underground palace of Famen Temple. It is more likely that they were fired before the method of sealing the gaps in the sagger with glaze water was invented.
At this time, Chen Wenzhe suddenly realized that secret color porcelain has always been a sagger, containing only one utensil.
The appearance of a piece of secret-colored porcelain means the shattering of a sagger!
It is absolutely impossible to use stack firing with this kind of firing technique.
It seems that this is the only way to maintain the smoothness of the glaze.
The further down he looked, the greater Chen Wenzhe's gains were. Only then did he realize that the secret color porcelain sagger was also very particular.
Their clay materials are more delicate than ordinary kiln furniture.
The materials used for the sagger are still the same, and the mud material of the secret-color porcelain body is even more fine-grained than ordinary celadon, and even the composition has changed.
In addition, after the firing is completed, the sealed sagger must be broken into pieces to reveal the true appearance of the finished product.
As a result, the cost is much higher and not something that the average class can afford.
Therefore, since its emergence, this kind of porcelain has been specially fired for nobles and royal families.
By this time, the main experience of this sagger has been almost finished.
Sure enough, the last piece of porcelain was put into the sagger, sealed, and sent to the kiln.
From then on, it was sealed in dust in the kiln until one day a thousand years later, it was washed away by heavy rain and flowed out of the rotten kiln mouth.
Finally, after several twists and turns, I came to Chen Wenzhe.
This is a well-preserved celadon sagger that has never been opened.
Therefore, the secret color porcelain that was put in back then is still there!
When he saw him, Chen Wenzhe was really filled with wonder!
However, he couldn't describe it accurately in words, he could only say it was beautiful!
You can't blame him for being uneducated. In fact, it has an indescribable beauty.
This is a lotus bowl, consisting of a bowl and a holder.
The bowl has a straight mouth, a deep belly, and ringed feet. The base of the cup is shaped like a bean. The mouth of the bowl is everted, the waist is girded, and the ringed feet are turned outwards.
The outer wall of the bowl, the surface of the bowl and the base of the bowl are all decorated with double lotus flowers, which look like bas-relief-like protrusions.
The porcelain body is off-white, fine and dense, and the particles are uniform and pure.
The lotus bowl is glazed with green glaze. The glaze layer is thick and consistent throughout, making it as smooth as jade.
Its shape is thick and dignified, with moderate proportions, smooth lines, plump and gorgeous, and the whole body is like a blooming lotus. It is ingeniously conceived and natural.
Let’s not talk about the craftsmanship. It must be as thin as paper and as bright as a mirror. The most important thing is the precious light all over its body. What’s going on?
I had seen pictures before, and I only knew that the secret-color porcelain looked like water, ice, and mist. But when I really saw it, Chen Wenzhe realized that the entire glaze was like a dream.
Thousands of green peaks are green in the end, right? The green is not deep, but it is dazzling.
It was not fire light, but a precious light.
The precious light is like autumn water? If the bottom of the porcelain is autumn water, what about the precious light on the surface of the porcelain?
What is this if it's not Baoshao? Chen Wenzhe is very suspicious. This is directly related to the precious porcelain Ru kiln of the Northern Song Dynasty.
Because of this kind of luster, he had seen it not only on copper-red glaze, but also on porcelain fired using Takara-yaki technique, which could achieve this effect.
Think about it carefully. In the previous production process of secret color porcelain, gem materials were added to it?
It seems that there is, because various mineral powders are added, and Chen Wenzhe can't tell what it is for a while. Besides, if you don't distinguish those natural minerals carefully, you really can't tell them apart.
Just like a diamond, there is no comparison between what it looks like without processing and what it looks like after processing.
"This thing must be related to Chai Kiln and Ru Kiln!"
Taking one last look at the small lotus bowl, Chen Wenzhe looked away.
As green as the sky, as bright as a mirror, as loud as a chime, and as thin as paper, these adjectives were first used on the legendary firewood kiln.
However, after seeing the Yue kiln's secret color porcelain, Chen Wenzhe knew that compared to the Chai kiln, it was not bad at all.
Besides, the final glory of Yue kiln may have overlapped with the birth of Chai kiln.
Finally, the Chai kiln must have been inherited by the Northern Song Dynasty. In other words, the Ru kiln was also inherited from the Chai kiln.
Legends and reasoning indirectly prove that the secret color porcelain, Chai kiln, and Ru kiln should be of the same origin.
Judging from the fine porcelain that was finally fired, there must be some connection between the secret color porcelain and the rumored "Chai Kiln".
Although the existence of "Chai Kiln" is still a topic of endless debate, at least in the documents of the Ming Dynasty, "Chai Kiln" appeared more than once as the first of several famous kilns.
The common explanation for the name "Chai Kiln" is that the later Zhou emperor Guo Rong's surname was Chai, and he was probably very good at the porcelain from a certain kiln, so he named the kiln after Chai to show his favor.
Zhang Yingwen's "Secret Collection of the Qing Dynasty" in the Ming Dynasty contains records that discuss kiln utensils, Bichai, Ru, Guan, Ge, Ding.
In the mountains around Shanglin Lake, there are scattered porcelain fragments from various eras. Some fragments from the Tang Dynasty that can be dated are already very thin, completely different from the thick and solid porcelain of the early Yue kilns.
Judging from the bottoms of two stacked bowls that failed to be fired and were excavated from the site, it is more likely that these fragments came from ordinary kiln mouths.
Even so, the thickness of the wall is only three to four millimeters, which is enough to explain the problem.
This is still the case in private kilns. The secret-color porcelain, which is only for imperial use, has to be "transparent and thin" in thickness, so naturally it is not a big problem.
Moreover, in the Five Dynasties, the porcelain making technology was more sophisticated than in the Tang Dynasty.
The common view now is that from the Tang Dynasty to the Five Dynasties, no porcelain type could compete with Yue kiln secret color porcelain in terms of quality, shape and artistic achievements.
The "Chai Kiln" represents the highest level of craftsmanship in this period. The combination of the two determines the uniqueness of the "Chai Kiln" as secret color porcelain.