The glaze firing process of Ru porcelain is still very critical. It mainly involves immersing the entire bisque-fired carcass in glaze water of moderate concentration, and using the water absorption of the carcass to absorb a certain thickness of glaze layer.
This method can make the thickness of the glaze layer of the utensils more consistent, making the operation simpler and more convenient.
Since glaze has a certain viscosity, after dipping in glaze, the glaze that is not fully absorbed is likely to remain on the rim of the vessel.
When the object is turned over and left to rest, this part of the glaze will gradually dry, forming a relatively thick glaze layer on the edge of the mouth or the bottom part.
Traces of this kind of craftsmanship can be seen in handed down vessels and unearthed vessels.
Of course, the cross section of the Ru porcelain specimen shows no signs of multiple glazing applications.
This proves that the glazing process is still a single glazing application, and the main factor in increasing the thickness of the glaze layer is the increase in the alumina content in the glaze.
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As the alumina content in the glaze increases, the high-temperature viscosity and melting temperature of the glaze increase.
This is conducive to the formation of thick glaze, resulting in the effect of piles of fat like jade.
Glaze firing is the last step in the Ru kiln porcelain making process, and it is also a crucial step.
The quality of glaze firing will have a very direct impact on the quality of your porcelain.
The kiln structure and the use of kiln furniture are the material basis to ensure the smooth progress of glaze firing.
When the Ru kiln is glaze firing, the heating, cooling process and oxidation-reduction atmosphere in the kiln, etc., and a series of firing indicators are called the firing system.
The firing system has left traces of craftsmanship on Ru kiln products. Through the traces of craftsmanship, we can get a glimpse of the precise mastery of the firing system by the ancients.
After firing is completed, the porcelain will crack during the natural cooling process.
This kind of crack in the glaze layer is actually a defect in the ceramic glaze.
But on the contrary, in the eyes of Northern Song Dynasty literati, this defect had a unique beauty and became one of the characteristics of Ru porcelain.
Glaze flakes, also known as flakes, are cracks in the glaze layer caused by the different expansion coefficients of the glaze during the firing process of porcelain.
The occurrence of chipping is itself a defect in the firing process.
The perfect combination of tire glazes should have the same expansion coefficients, so that the glaze surface does not crack.
However, this unique skill was difficult to achieve in the Song Dynasty. Due to the relationship between the materials and the firing process, it was generally impossible to achieve the level of no opening.
The only unmarked piece of Ru porcelain handed down from generation to generation is the azure unmarked narcissus basin hidden in the Wanwan Forbidden City.
This Song Dynasty cultural relic became an alternative among porcelains due to flaws, and later became a national treasure among national treasures.
This is a legendary piece of porcelain, which was born in the Ru Kiln of the Song Dynasty in my country.
It once entered the imperial palace only for royal use, and it even had a story with Emperor Qianlong that has been passed down to this day.
The real reason why it has become a national treasure among national treasures is precisely because it was once a substandard product.
Will substandard products become national treasures? This is impossible, it is really possible.
The most famous porcelain in my country was produced in the Song Dynasty.
The five famous kilns, Guan Kiln, Ge Kiln, Ru Kiln, Ding Kiln and Jun Kiln, are world-famous.
"Song porcelain is the best in the world", and "Ru kiln is the best".
This Ru kiln, which ranks first among the five kilns, was originally produced in Ruzhou.
At that time, Zhou Shizong Chai Rong ordered people to bake a kind of porcelain called Chai kiln, which was the earliest Ru porcelain.
Ru porcelain has two characteristics that are different from other porcelain. First, the glaze color is unique, between blue and green, just like the first touch of blue exposed after the rain and the clouds disperse.
After the rain, the blue clouds break the virginity, and the color is like the future. This is Ru kiln.
Another unique feature of Ru porcelain is that during the firing process, due to the different expansion degrees of the matrix and glaze, the fired Ru porcelain will naturally form fine and uniform cracks.
Usually, we call it opening, and people also evaluate the quality of your porcelain based on the opening.
In the Northern Song Dynasty, thanks to the obsession of the artist Emperor Song Huizong, the style of Ru porcelain became more simple and beautiful.
The color is more elegant and calm, and the glaze is as moist as jade.
So far, Ru porcelain has successfully defeated all opponents and reached the pinnacle of ancient Chinese porcelain.
However, what is unexpected is that in the late Northern Song Dynasty, due to the invasion of Jin soldiers, all Ru kilns were abandoned and all Ru porcelain was destroyed, and the extremely exquisite refining skills of Ru porcelain were lost.
At this point, every piece of Ru porcelain handed down from generation to generation is a national treasure.
The azure and patternless narcissus basin we are going to talk about today is now hidden in the Wanwan Forbidden City.
The shape of this azure, grainless narcissus basin is based on the wooden basins of the Song Dynasty. Its outline is simple and elegant, with only a few straight lines throughout.
Several perfect curves form the same simple plane.
It is dignified, gentle and elegant.
Not only does it inherit all the advantages of Ru porcelain such as its simple and smooth shape, and its azure glaze, which is quiet and cool, but the most unique thing is that it does not have a single crack in its entire body, making it absolutely unique among Ru porcelains.
At present, among all the Northern Song Dynasty Ru porcelains in the world, there is no open piece. This is the only one.
The magic of this azure and patternless narcissus basin goes far beyond that. There is also a legendary story attached to this special piece of Ru porcelain.
This azure, patternless narcissus basin was born in the Northern Song Dynasty. Perhaps because it was not opened, it was an unsuccessful piece of Ru porcelain and was thrown into Ouchi's warehouse.
Because I sat on the bench, I escaped war after war and destruction again and again.
In the blink of an eye, in the Qing Dynasty, no one cared about the existence of the azure patternless narcissus basin.
It was placed haphazardly in the corner of the treasury, gathering dust.
That year, Emperor Qianlong had some free time and discovered two kittens at the corner of the palace.
He felt that the two kittens were pitiful, so he ordered the eunuch to build a nest for them.
The emperor opened his mouth and the eunuch ran away and broke his leg.
The cat's nest was quickly set up, but there was no feeding basin for the cat.
This was absolutely not possible, so one of the eunuchs came to the treasury and asked the eunuch guarding the treasury for a cat food bowl.
Who dares to be careless in the emperor's errand?
The eunuch who was guarding the treasury opened the door of the treasury and gave the dusty azure patternless narcissus basin to the eunuch who was building the cat's nest.
Half a month later, Emperor Qianlong suddenly remembered the two kittens.
He came to the scene to check and found that the azure and patternless narcissus basin had been licked by the cat and no dust was left at all.
Although there are still cat food residues hanging on it, under the shining of the eyes, it shines with a breathtaking "treasure light".
Logically speaking, the unopened azure and patternless narcissus basin is a defective product.
Precisely because of its uniqueness, it has become a unique masterpiece in the world.
This "defective product" from Ru kiln did not become depressed or give up on itself because of others' disdain.
It has been waiting "silently" for hundreds of years, and finally waited for its "Bo Le" to appreciate it, albeit in the form of a cat food bowl.
The azure, patternless narcissus basin was regarded as a treasure and placed in front of Qianlong.
Qianlong also wrote a poem for him: "The official kiln should not distinguish between the Song Dynasty and the Tang Dynasty. The fire is not kept alive. It is a false food utensil, but the Cu Ping knows how to repay the kindness of the pig (a cat still knows how to be grateful to its owner when it has gained weight)."