What are the characteristics of classic Ru kiln porcelain that you don't know?

2. General situation of the development of north and south blue porcelain kiln industry before the emergence of Ru Ci.

Before the appearance of Ru Ci, celadon had experienced a long period of development, and celadon kilns in the north and south had accumulated a lot of technical experience, which laid an important foundation for the appearance of Ru Ci.

2. 1 Overview of the development of southern celadon kiln industry before the emergence of Ru Ci.

Shaoxing, Zhejiang, called Yuezhou in ancient times, is the origin of celadon, called Yueyao. This area is rich in "high silicon and low aluminum" porcelain stone, which can be fired in the range of1150℃-1250℃. Yue kiln took the lead in firing celadon at the end of the Eastern Han Dynasty, and led the development of celadon for a long time in the following hundreds of years. It is the most important and representative celadon kiln mouth in South China. The glaze of celadon in Yue kiln has a strong luster, but the glaze layer is thin and transparent, and the reduction rate of iron in the glaze is not high (between 40% and 45%), and the glaze color is yellow-green. After the middle Tang Dynasty, with the rise of tea drinking, the demand for porcelain tea sets increased greatly, which promoted the development of celadon technology in Yueyao. Yueyao celadon reached its peak from the middle Tang Dynasty to the Five Dynasties. With the rapid development of technology and high level, high-quality celadon "secret color porcelain" has been fired for official use. The reduction rate of iron in secret porcelain glaze is as high as 55%, and the glaze color is cyan. The high reduction rate of the secret color porcelain glaze benefits from the strong reduction atmosphere created by the sealed sagger process, which is an important innovation of the cross-kiln process and can be used for reference by Ru Ci. The "glaze" of Yue kiln celadon is thin and transparent, which is suitable for describing the comprehensive decoration technique of combining printing, plastic and glaze. The technology and decoration technology of Yue Kiln have influenced many celadon kilns in the north and south.

2.2 General situation of the development of northern celadon kiln industry before the emergence of Ru Ci.

The firing age of celadon in the north is later than that in the south, which is related to the "high aluminum and low silicon" raw material for porcelain making in the north. This raw material needs a high firing temperature (above 1300℃), so it is difficult to fire. Before Ru Ci appeared, Yaozhou Kiln was the most important celadon kiln in the north. Yaozhou Kiln is located in Yaoxian County, Shaanxi Province. In the Song Dynasty, it was called Yaozhou, hence the name Yaozhou Kiln. Yaozhou Kiln is greatly influenced by Yue Kiln, and Lu You wrote in Notes of Laoxuean that "Yaozhou celadon is called Yue Kiln, which is similar to Yuyao County in secret color". The Northern Song Dynasty witnessed the fastest progress in porcelain-making technology and the highest quality of celadon in Yaozhou kiln. The firing temperature is as high as 65,438 0,300℃, and the olive green glazed celadon with good luster and transparency is produced. The overall style is similar to celadon [65,438+0] carved in Yue kiln, and the iron reduction rate of olive green glaze is about 60%. The celadon of Yaozhou Kiln was selected as tribute porcelain in the Northern Song Dynasty because of its excellent quality, which had a wide influence and was imitated by many kilns in the North. Kilns in central and western Henan are deeply influenced by Yaozhou Kiln, and also burn celadon, which is classified as Yaozhou Kiln Celadon, including Deng Kiln (Neixiang Kiln), Yuzhou Kiln, Linru Kiln, Xin 'an Kiln and Yiyang Kiln [2], among which Linru Kiln is the mother of Ru Kiln.

3. The emergence and innovation of Ru Ci.

Henan was an important porcelain producing area in the Northern Song Dynasty. Ru Ci is from Ruyao, and the kiln site is in Qingliangsi Village, Baofeng County, Henan Province. In Song Dynasty, Baofeng belonged to Ruzhou (formerly Linru County), so it was called Ruyao. The appearance of Ru Ci is the result of further innovation on the basis of inheriting and integrating the techniques of celadon from the North and the South.

3. 1 Ru Ci was influenced by Yueyao and Yaozhou kilns.

Yue Kiln and Yaozhou Kiln have an important influence on the emergence and development of Ru Ci. Yueyao once led the development of celadon for a long time. Secret color porcelain is the top celadon fired in Yue kiln, which inherits the glaze color and firing process of secret color porcelain. In the Northern Song Dynasty, Xu Jing said that "the ancient secret color of Yuezhou is similar to that of Ruzhou's new kiln", and the "ancient secret color" in the paper is celadon with the secret color of Yueyao, which shows that the glaze color of Ru Ci is very close to that of the secret color porcelain. In the late Tang Dynasty and the Five Dynasties Yue Kiln, sealed sagger technology was used to enhance the reducing atmosphere in the sagger, improve the iron reduction rate, and fire the green glaze and secret color porcelain. Ru kiln adopts sealed sagger firing technology, which shows that they are technically inherited.

Due to the proximity of raw materials and geographical location, during the Northern Song Dynasty, there were many kilns in Henan that imitated Yaozhou Kiln to carve celadon, and Linru Kiln was one of them. These kiln products have fierce competition, frequent technical exchanges and rapid development. Before the mid-Northern Song Dynasty, the official porcelains were mostly Yueyao celadon and Ding Yao white porcelain. After the mid-Northern Song Dynasty, Yue Kiln gradually declined. Ding Yao's mouth is too rough to use due to the process of over-firing, and the government needs to find a new substitute. The mouth of Henan Celadon Kiln near Bianjing entered the official view, and Ru Ci was born under this background. In Tan Zhai in the Southern Song Dynasty, it was written that "the white porcelain kiln in Dingzhou in this dynasty was useless, and Ruzhou was ordered to be a green kiln, so it was well known to Tang, Deng and Yaozhou in Hebei Province, and Ruyao was the first". According to this document, Ru kiln was born out of Linru kiln and developed on the basis of Linru kiln. Because of its excellent products (Ru Ci), Linru kiln was selected as a tribute kiln by the government, and it belongs to the celadon system of Yaozhou kiln.

3.2 Ru Ci's development and innovation in glaze color and technology.

As an official tribute porcelain, Ru kiln innovated the glaze color of celadon and created "azure glaze" on the basis of Yue kiln and Yaozhou kiln. The iron reduction rate of azure glaze is as high as 72%, with blue opalescence, soft glaze and jade texture, which has the subtle and elegant aesthetic temperament of Song Dynasty. In order to produce Ru Ci with green glaze, Ru kiln craftsmen have made a series of innovations and improvements in celadon technology, which are mainly manifested in three aspects: first, they have created the technology of secondary firing and thick glaze, and second, they have improved the structure and firing process of the kiln. Thirdly, effective control of sintering temperature and atmosphere. The secondary thick glaze firing technology is to fire the molded clay blank at low temperature (about 800℃) to enhance the mechanical strength of the blank, facilitate repeated glaze application and increase the thickness of the glaze layer. After firing, the glaze color is uniform, the jade texture is strong, and the glaze defects are few. Temperature and atmosphere are the keys of sintering technology. In order to control the kiln temperature, Ruyao newly built a small oval kiln with a small kiln room area, and adopted a sealed sagger firing process to improve the reduction rate of iron [3]. The opacification of azure glaze is closely related to firing temperature. The firing temperature should be controlled between1150-1200℃, otherwise the glaze will become transparent. In order to accurately control the sintering temperature and atmosphere, Ru kiln craftsmen adopted ignition and cake insertion technology to help observe the sintering effect and determine the timing of heating, heat preservation and ceasefire. These technological innovations and improvements are the important guarantee for the successful firing of Ru Ci glass. The appearance of azure glaze highlights the aesthetics of celadon material itself. Without other decorative techniques such as carving, painting, printing and molding, plain Ru Ci decorated with glaze appeared, which subverted the comprehensive decorative techniques of transparent glazed celadon in the past. Su Ru Ci is considered to be the most recognizable Ru Ci, because its pure glaze and jade-like texture complement the shape of the vessel. Figure 1 is the azure glaze work of Ru Ci in the Northern Song Dynasty.

Photo 1 Three-legged string furnace in Ru Ci in Northern Song Dynasty

4. The influence of Ru Ci

The appearance of Ru Ci reflects that in the process of celadon development, with the progress of technology, the quality of celadon is getting better and better, and the aesthetics of celadon materials is outstanding. Ru Ci's repositioning of celadon aesthetics and its technological path directly contributed to the successful firing of celadon and Jun porcelain in the Northern Song Dynasty, and had an important influence on celadon in the Southern Song Dynasty.

4. The influence of1Ru Ci on the celadon and Jun porcelain of official kilns in the Northern Song Dynasty.

After the appearance of Ru Ci, historical records recorded that the Northern Song Dynasty officials fired celadon in the kilns built by Bianjing during Daguan and Zhenghe years, which was called the Northern Song Dynasty official kilns. However, the kiln site has not been found so far, and its glaze color characteristics and technological characteristics can only be inferred from the official kiln works handed down from ancient times. The glaze color of celadon in the official kiln of the Northern Song Dynasty has three characteristics: first, the pink celadon glaze is opaque and jade-like; Second, the thin glaze along the mouth shows the tire color, and the foot does not show the tire color, which is called the purple mouth iron foot; The third kind is ice crack glaze with different shades, called gold wire. The combination of purple iron foot, gold wire and jade powder green glaze presents a dignified artistic aesthetic feature, which enriches the texture of the official kiln green glaze, as shown in Figure 2, the Northern Song Dynasty official kiln strung bottles. Mr. Chen Wanli once compared the Ru kiln celadon collected by the Palace Museum with the official kiln celadon of the Northern Song Dynasty, and found that the glaze color of the two celadons was very similar, and the craftsmanship showed the characteristics of the same strain. From this, it can be inferred that the celadon fired by the official kiln in the Northern Song Dynasty cannot be separated from the skilled porcelain-making skills of Ru kiln craftsmen [4].

Fig. 2 Schematic diagram of the string-pattern bottle in the Northern Song Dynasty official kiln.

Jun porcelain is a kind of high-quality celadon product which was fired in Yuzhou, Henan Province at the end of the Northern Song Dynasty. The main colorant of Jun glaze is still iron, and the reduction rate of iron is close to that of Ru Ci (above 70%), and it also contains a small amount of copper (copper turns red after reduction). Jun glaze is characterized by distributing one or several purple spots on a large area of blue opalescent glaze, which is called "kiln change". Jun porcelain is known as "kiln glaze". The appearance of Jun porcelain was greatly influenced by Ru Ci, and Yuzhou and Baofeng were geographically close. After the appearance of Ru Ci, some kilns in Yuzhou thoroughly studied and imitated the technology of Ru Ci, and used local raw materials to fire Jun porcelain. During the period of 1975, Henan Provincial Museum made an archaeological excavation of Juntai Kiln in Yuzhou, and found that Juntai Kiln is a comprehensive kiln, and the process of firing and jun porcelain adopts the secondary firing method and thick glaze technology pioneered by Ru Kiln [5]. From 200/KLOC-0 to 2002, Peking University China Archaeological Research Center and Henan Archaeological Research Institute excavated the site of Liujiamen Jun Kiln in Shennan Town, Yuzhou, and found that the technology of Liujiamen Jun Kiln is in the same strain as that of Ru Kiln.

4.2 Ru Ci's influence on the celadon of Guan Kiln and Longquan Kiln in Southern Song Dynasty.

Ru Ci had an important influence on the celadon of official kilns in the Southern Song Dynasty. At the end of the Northern Song Dynasty, Bianjing Imperial Kiln ended with the collapse of the Northern Song regime. After the regime moved south, a new kiln was established in Hangzhou, which was called the official kiln of the Southern Song Dynasty. In "Tan Zhai Bi Heng", Ye Jian recorded the inheritance relationship among Ru Kiln, Northern Song Dynasty Official Kiln and Southern Song Dynasty Official Kiln as follows: "The white porcelain in Dingzhou was too strong to be used, and Ruzhou was ordered to be a green kiln, so Tang, Deng, Yaozhou and other places in Hebei learned that Ru Kiln came first. ....................................................................................................................................................... When ........................... Zhongxing crossed the river, Shao raised the backyard, which was named Shao Bureau, attacked the Beijing Heritage System, built a kiln to repair the internal division, made celadon, and named the internal kiln. Clear mud is a model, extremely exquisite, bright and clean glaze, which is precious in the world. There is a new kiln under the altar in the back suburb, which is bigger than the old kiln. " From this document, we can know that Ru kiln, Northern Song official kiln and Southern Song official kiln are in the same strain in porcelain making technology. Two official kiln sites in the Southern Song Dynasty recorded in historical materials have now been discovered. Scholars have done a lot of technical analysis and experimental replication on the celadon samples of the official kiln in the Song Dynasty to verify the literature records. 198 1 Shanghai Institute of Silicate, China Academy of Sciences cooperated with Kaifeng Arts and Crafts Experimental Factory, Henan Province, to replicate the official kiln of the Northern Song Dynasty with local porcelain-making materials in Henan Province. Replication is based on the inheritance relationship that the official kiln in the Northern Song Dynasty was technically influenced by Ruguan kiln, and then the technology was transmitted to the official kiln in the Southern Song Dynasty. Based on the research and analysis results of Ru Guan Kiln celadon and Southern Song Guan Kiln celadon, the result is that the microstructure of the reproduced powder celadon glaze is very similar to that of Northern Song Guan Kiln celadon [6].

Ru Ci indirectly influenced the celadon of Longquan kiln in the Southern Song Dynasty through the official kiln in the Southern Song Dynasty. Longquan kiln is the most famous celadon kiln mouth in Zhejiang Province after Yue kiln. The central kiln is located in Longquan, Zhejiang, hence the name Longquan kiln. Early Longquan kiln celadon works are similar to Yue kiln. After the mid-Southern Song Dynasty, the celadon style of Longquan kiln changed greatly, but it was obviously not the inevitable result of the evolution of its own traditional craft, but was directly influenced by another culture, which came from the official kiln of the Southern Song Dynasty [7]. The influence of porcelain-making technology of official kiln in Southern Song Dynasty on Longquan kiln has been confirmed by archaeological data. Longquan Kiln in Southern Song Dynasty adjusted glaze formula and adopted secondary firing and thick glaze technology to produce celadon with pink glaze and plum glaze. The iron reduction rate of the two celadon glazes is above 75%, and the jade texture is very strong, which pushes the beauty of celadon glaze to the peak.

During the Ming and Qing Dynasties, blue-and-white porcelain, glazed porcelain and various colored glazed porcelain rose, while celadon declined, but Ru Ci still had a lasting influence. Jingdezhen Imperial Kiln Factory in Ming and Qing Dynasties once copied many Ru Ci with the glaze color characteristics and craft route of Ru porcelain, which is the masterpiece of celadon in Ming and Qing Dynasties.

5. Conclusion:

Ru Ci plays a connecting role in the history of celadon development. Before Ru Ci appeared, celadon glaze was bluish yellow, and the glaze layer was thin and transparent, mostly for comprehensive decoration. The appearance of Ru Ci is the result of inheriting and innovating the technology of celadon in the north and south. The azure glaze created by Ru Ci is like jade, and the aesthetics of celadon material itself is outstanding. Ru Ci's repositioning of celadon aesthetics and its technological path have influenced a series of celadon with "glaze" as the aesthetic subject, such as official kilns in the Northern Song Dynasty, Jun kilns, official kilns in the Southern Song Dynasty and Longquan kilns.