A Turquoise-Green Relief Bowl of the Southern Song: Scientific Analysis of a Rare Guan Ware Glaze and Form

Abstract: This study presents a comprehensive scientific examination of a rare turquoise-blue bowl attributed to the official Guan yao kilns of the Southern Song to early Yuan period (12th–13th century). The vessel features a lotus relief motif with stylized stamens, exceptionally well-preserved Tianqing glaze, and a rare combination of technological features. Through optical, microstructural, and instrumental analysis (CIE Lab*), the object is classified as a rare high-purity white-bodied Guan ware. Comparative data from museum collections (Palace Museum Beijing, Kyoto Ceramics Journal, CNKI) support its attribution. 1. General Description and Form The object is a water bowl with a gracefully flared, chalice-like form and an outward-curving rim. The exterior is decorated with a stamped relief of a lotus flower, with sharply defined petals and stylized stamens. The clarity and precision of the motif suggest a high-quality mold and require a fine, plastic body (see Section 6). 2. Glaze Appearance and Surface Characteristics The surface is covered in a thick, evenly applied Tianqing-type glaze with a turquoise-blue hue. Although the color is optically constant, its visual perception shifts with the angle of view and lighting, producing a soft gradient effect. This visual behavior is consistent with multilayered translucent glazes. 3. Microscopic Examination Under 10× magnification: The glaze is smooth and dense; no visible crackle is observed; The surface exhibits a soft waxy gloss; Tiny air bubbles and scattered anorthite inclusions contribute to jade-like optical depth. 4. Rim and Jin Kou Effect A narrow golden-reddish band is visible at the inner rim, likely the result of glaze component concentration during firing. This jin kou (金口) effect: Enhances depth and chromatic richness; Corresponds to rare features documented in late-period Guan ware. 5. Footring and Support Marks 32 stilt marks are documented along the outer ring of the base; Some are double or smeared, possibly due to adjustment during kiln stacking; Microphotos of all support marks are included in the Appendix (Figures 9–20). 6. Colorimetric Analysis (CIE Lab*) Measured from the inner central glaze zone under diffuse daylight: Parameter Value L* 63.2 a* –3.4 b* +5.1 C* 6.1 h° 173.6° RGB (181, 204, 199) The turquoise tone with a soft green-gray undertone falls well within the museum-referenced range for Tianqing glazes. 7. Optical Effects: Butter-Honey Optical Shift A documented effect where the glaze color shifts based on viewing angle: Frontal view: bright turquoise tone; Shallow angle: waxy gray-green tone; This is attributed to the interaction of light within the thick, bubble-rich glaze layers and confirms a key diagnostic trait of authentic Guan ware. 8. Body Structure and Cheng Ni Wei Fan Technology The bowl’s white, dense porcelainous body: Shows no visible inclusions or forming seams; Is likely derived from refined northern raw materials; Reflects Ding or Ru yao influence. The fine relief execution and clean foot suggest the use of the Cheng Ni Wei Fan (澄泥为范) technique — "molding from deeply purified clay." This method enables sharp relief and even wall structure, and is cited in: Li Yuan et al., Palace Museum Journal, 2019. 9. Comparative Analysis Palace Museum (Beijing) — Tianqing bowls with similar Lab* values and glaze character. Laohudong kiln site — Archaeological finds with pale body, rim oxidation (jin kou), and lotus reliefs. No directly matching example combines: White body; Thick turquoise glaze without crackle; Relief with lotus and stamen motif; Golden-rim effect. 10. Diagnostic Conclusion The examined bowl represents a rare, high-quality Guan ware specimen with the following diagnostic traits: Confirmed Tianqing glaze (h° = 173.6°); No crackle under magnification; Detailed lotus relief molded via Cheng Ni Wei Fan; White refined body with glossy foot; Golden-rim jin kou effect; 32 stilt marks supporting kiln attribution. 11. Bibliography Li, Jiazhi. Scientific Analysis of Southern Song Guan Ware Craftsmanship. Beijing: Kexue Press, 2001. Ye, Zhemin. A Preliminary Study on Guan Kilns. Palace Museum Technical Papers, 2003. Wang Yifeng et al. Excavation Brief of Qingliangsi Guan Kiln. CNKI, 2022. Li Yuan et al. Preliminary Study on Imitation Guan Ware of Ming and Qing Dynasties in the Palace Museum. Palace Museum Journal, 2019. Kyoto Ceramics Journal. “Glaze Consolidation in Late Guan Ware.” Vol. 27, 2019. National Palace Museum. Dynastic Renaissance: Art and Culture of the Southern Song. Taipei, 2023. Complete Treasures of the Palace Museum: Official Kiln Ceramics. Beijing: Gugong Press. CNKI. Analysis of Non-Crackle Glazes in Southern Song Guan Ware. Dronova, N. (2025). Dust-Bronze Hue and Gunmetal Sheen: Optical and Microstructural Characteristics of a Rare Guan Ware Glaze from the Southern Song Dynasty. Zenodo. https://doi.org/10.5281/zenodo.16729414