Bridging the crafts: lead isotopes reveal the innovation of lead-glazed pottery in Warring States China

This study reassesses the origin of low-fired lead-glazed pottery in ancient China through a systematic analysis of seven excavated specimens from the ancient Linzi City, the capital of the Qi State, dated to the late Warring States period (300–221 BCE). By integrating archaeological context, compositional and lead isotopic analysis, the research establishes these ceramics as the earliest scientifically verified lead-glazed pottery in China. The findings indicate that these wares were produced using a standardized technological protocol, locally sourced clay bodies coated with high-lead glazes (50–62 wt% PbO), exclusively colored by iron oxide (Fe2O3), and fired in a reducing atmosphere, which represent a rather different process compared to the typical Chinese lead glaze technology since the Western Han dynasty (202BCE-8CE). Moreover, lead isotopic data attribute the lead source to highly radiogenic deposits that were locally available and mined for Qi bronze production, revealing a shared lead supply to both ceramic and metallurgical production. The study argues that the initial development of lead glazing emerged as a result of cross-craft interaction involving ceramic production, proto-porcelain, lead-barium siliceous materials, and, most significantly, leaded bronze manufacturing. These findings contribute to the ongoing debate regarding the earliest lead-glazed pottery, underscore the significance of cross-craft interactions in technological innovation, and reframe the Qi State as a key center for early ceramic experimentation.