Prof. Nona Dronova Doctor of Technical Sciences, Professor of Traditional Arts, St. Petersburg📖 Published in: Nona Dronova, "What You Must Know About Ancient Chinese Porcelain", Moscow, 2016, p. 13. ISBN: 978-5-9908782-6-6 📄 Abstract This study presents a comprehensive diagnostic analysis of a flower-shaped bowl attributed to the Guan yao (official kiln) tradition of the late Southern Song – early Yuan period. The bowl features a thick, icy Tianqing-type glaze with natural crackle, an iron-burnt unglazed foot, and a violet halo at the rim — all strongly consistent with official kiln standards. Microscopic examination reveals a fine crystalline glaze texture, a natural crack network without artificial staining, and precise glaze-body transitions. Additionally, instrumental color analysis confirms the grey-green tone as belonging to the “stony” Tianqing glaze subtype, further supporting attribution. The object is published in the author’s monograph and is proposed as a diagnostic reference for authentic Guan yao ware. 🏺 Object Description Catalogue No.: GE-FL-11-CB-01 Title: Flower-shaped bowl with icy Tianqing glaze Date: Late Southern Song – early Yuan (12th–13th c.) Attribution: Guan yao, Laohudong kiln system Material: High-fired porcelain with Tianqing-type glaze Dimensions: 11 cm diameter × 7 cm height Shape: Chrysanthemum form with petal-like lobes Foot: Unglazed, iron-burnt with visible shrinkage line and violet optical zone Glaze: Grey-green, glassy, with fine icy crackle and oily translucency 🔬 Diagnostic Features Confirming Authenticity 1. Natural Ice Crackle Glaze The glaze surface exhibits dense, naturally formed ice crackle (tianlan wen 天蓝纹) without pigment infill — typical of official Song wares. Figure 1. Underside of the bowl showing unglazed foot, icy Tianqing glaze, and violet halo. 2. Microstructure of the Glaze Under magnification, the glaze shows a uniform microcrystalline matrix and soft internal reflection, suggesting a high degree of glaze purification. Figures 2 & 6. Close-up of crystalline surface with subtle reflectivity and light diffusion. 3. Crack Anatomy and Iron-Rich Edges Natural cracks are deep, sharp, and exhibit localized iron-rich edge deposits under magnification. Figure 3. Clean crack structure with reflective surface and no artificial enhancement. 4. Glaze–Body Transition The glaze terminates cleanly with a well-defined shrinkage line above the iron-burnt foot zone, confirming high-temperature reduction firing. Figure 4. Interface between glazed wall and burnt foot. 5. Violet Optical Halo A violet to lavender optical hue is observed at the glaze cutoff — a rare and authentic optical phenomenon seen in high-end Guan yao specimens. Figure 5. Violet tinge at iron-burnt rim due to reduction atmosphere. 🎨 Instrumental Color Analysis The glaze color was sampled using digital imaging under calibrated lighting conditions: RGB: (151, 160, 148) HEX: #97a094 This color matches a light, muted grey-green tone, characteristic of the “stony” subtype of Tianqing glaze (天青釉). It shows: High lightness Low chroma (desaturated tone) Cool neutral undertone Such color properties are consistent with late Southern Song official kilns, especially for refined ritual bowls and incense vessels produced in Laohudong workshops. 📘 Comparative References Museum Comparable Object Shared Features Palace Museum (Beijing) Guan yao flower-shaped bowl, cat. F1957.12 Same crackle, foot structure, glaze tone Freer Gallery of Art (Washington DC) Chrysanthemum bowl with Tianqing glaze (F1909.27) Identical shape, violet halo, and oily translucency ✅ Conclusion The flower-shaped bowl GE-FL-11-CB-01 exhibits a full set of diagnostic markers consistent with authentic Guan yao wares of the late Southern Song to early Yuan period. Its glaze tone, violet halo, crackle morphology, and microstructure match known standards from major collections. The piece is recommended as a diagnostic benchmark for researchers and institutions working with Song official ceramics. 📎 Figures and Captions Figure Description Fig. 1 Underside of bowl with icy crackle glaze and violet halo on iron-burnt foot Fig. 2 Microcrystalline Tianqing glaze texture under magnification Fig. 3 Detail of natural crack with iron edge and internal light reflection Fig. 4 Glaze–body interface with visible shrinkage line Fig. 5 Violet-lavender tinge at glaze cutoff (optical firing effect) Fig. 6 Uniform microstructure of Tianqing glaze with natural crackle 📚 Reference Publication This bowl is published and fully documented in: Dronova, Nona. "What You Must Know About Ancient Chinese Porcelain", Moscow, 2016, p. 13.ISBN: 978-5-9908782-6-6 🔑 Keywords Guan yao, Tianqing glaze, Song dynasty ceramics, Ge ware, official kilns, crackle glaze, reduction firing, violet halo, ceramic diagnostics, flower-shaped bowl, Southern Song porcelain, Chinese art history

The scientific study of ancient Chinese porcelain, particularly from the official kilns (Guan yao, Ru yao, Ge yao) of the Song dynasty, requires a comprehensive, multidisciplinary approach. Authentic pieces often exhibit subtle visual and material features — such as crackle morphology, glaze tone, microstructure, and firing traces — which can only be reliably identified through the combination of: Visual microscopy Instrumental colorimetry (CIE Lab, RGB) Glaze–body interface analysis Comparative museum reference mapping This integrative method allows scholars to distinguish genuine imperial wares from later imitations with a high degree of certainty. Such diagnostics not only aid in scholarly attribution but also help define new reference standards for museum collections and international authentication protocols.