The introduction of celadon production in North China: Technological characteristics and diversity of the earliest wares

Abstract

Celadon, technically a stoneware with a lime-rich glaze, had been produced in South China for more than two millennia before it was first made in the North in the second half of the sixth century. It appears to have been an immediate precursor to white porcelain, which was first produced by northern kilns. The compositions and microstructures of early northern celadons from kilns, residential sites and tombs in Shandong, Hebei and Henan provinces, and dated 550s-618 CE, have been determined by SEM-EDS. The majority of the vessels were made using a low-iron kaolinitic clay, with high alumina (20-29%), as anticipated for northern clays. A small number of celadon vessels from a kiln at Caocun, which produced mainly lead-glazed wares, have lower alumina contents and appear to have originated in the South. It seems possible that these imported vessels were being used by the potters as models on which Caocun wares were based. Consistent differences in major element composition are observed between the products of kilns at Anyang, Xing, Luoyang and Zhaili. Unlike southern celadon glazes, which were prepared as two-component mixtures of vegetal ash and body clay, the northern celadon glazes are three-component, and typically contained an additional siliceous component, probably loess. An exception is the glazes of the Xing celadons, which present no evidence for loess but which are rich in Na2O. The source of the soda is unclear, common salt and albitic feldspar are discussed as possibilities. Based upon micromorphological characteristics such as the relative size and abundance of remnant quartz and the extent of observable mullite, as well as the position of the glazes in the CaO-Al2O3-SiO2 phase diagram, the Xing bodies are more mature and they appear to have been fired to higher temperatures than the products of other kilns. These results suggest that celadon technology was not directly transferred to the North from the South, but that the northern potters adopted their own strategies to make high-fired glazes. Furthermore, each kiln appears to have had its own preferred recipe, to suit the available raw materials. The products of Xing kiln were exceptional and it appears that here the trajectory towards white porcelain was already apparent, perhaps reflecting the creativity of the Xing potters who were among the first to make a successful white porcelain.

Tracing the origin of Chinese early white porcelain in the late sixth century—evidence from Xing kiln

“…Titanium and iron oxide are both present, with contents in the range of 0.54–0.79 wt% and 1.55–2.13 wt%, respectively. The glazes have a high level of calcium oxide (10–15 wt%), and the total quantity of K 2 O and Na 2 O in the glazes is generally between 2 wt% and 7 wt%, which is consistent with previous research on the early Xing wares (Huang et al, 2020; Ma, Ma, et al, 2018; Ma, Zhao, et al, 2021). The contents of Fe 2 O 3 and TiO 2 are in the range of 1.01–2.41 wt% and 0.13–0.50 wt%, respectively, causing variances in the glaze hues of the samples among white, green, and yellow.…”

Searching for the earliest use of limestone as a flux in Chinese high-fired ceramic glazes—evidence from Sr isotopic analysis of Chinese northern porcelain

“…Green glazed stoneware was the first high-fired ceramic made in North China and the technological precursor of early northern porcelain. It has been suggested that the northern green stoneware glaze was created following the original southern recipe: wood ash plus body material (Huang et al 2020). The Sr isotopic compositions of our Gongyi green stoneware glaze samples are very consistent at 0.715-0.718 for 87 Sr/ 86 Sr and 300-350 ppm for Sr concentration (Figure 1).…”

“…The results of Sr isotope and chemical analysis of our early porcelain samples from Xing kilns show that body material was not the sole siliceous material in the glaze formula. Although green stoneware glaze from Xing kilns is not studied in this work, from its chemical composition reported in Huang et al (2020), we can see that it has a very similar chemical composition to Xing early porcelain, and there is also a Na 2 O content discrepancy between Xing green stoneware body and glaze which suggests that another raw material, apart from body material and wood ash, was included in the glaze recipe.…”

“…Halophytic plant species are tolerant to alkalies including Na + and are therefore exceptions to this rule; their ash can contain over 10 wt% Na 2 O. The non-halophytic plant ashes originating from the loess landscape have low Na 2 O contents of less than 1 wt% as many data show (Kerr andWood 2004, Li et al 2019b), and this is also confirmed by many chemical compositions of wood ash glazes made at production sites located in the loess dominated area (Shen et al 2019, Huang et al 2020. Therefore the Na 2 O content in the glaze must have derived from a material other than the body and wood ash.…”

“…The key to pinpointing when and where limestone was first used in glaze making is to work out from which varieties of glazes we should look for the answers. It has been repeatedly proven that green stoneware glaze, which was the earliest high-fired ceramic glaze in China, was a wood ash glaze; and southern Qingbai glaze was a limestone based glaze 1 according to historical records and scientific evidences (Huang et al 2020, Ma et al 2014. A recent study suggested that the earliest use of limestone in glaze recipes at Jingdezhen, South China occurred before Qingbai ware was first produced and the early use of limestone at Jingdezhen could have been under the influence of northern porcelain makers (Wu et al 2020).…”