Analysis of Residues in Pottery Vessels Unearthed at the Zhenjiang Tiansheng Daoist Temple and a Discussion on the Daoist Alchemical Vessel ‘Yangcheng Jar’

ABSTRACT This study scientifically analyzed nine special‐purpose pottery vessels and their residues from the Tian Sheng Temple Daoist Site in Zhenjiang. Using advanced techniques like SEM‐EDS and micro‐Raman spectroscopy, the research identified that the vessels' structure (shallow body, wide mouth, pointed base) aligns with the prolonged and controlled heating required by external alchemy (waidan). The residues were primarily lead oxide, containing a compact composite of porcelain fragments and lead phase. This suggests the vessels likely functioned as ‘Elixir mother’ (danmu), a medium used to guide reactions, highlighting the regional persistence of specialised alchemical techniques within institutionalised Daoist centres during the Song‐Yuan period.