Manufacturing technology and lead provenance of bronze vessels from the Wanggang Cemetery (475–338 BCE), Huaibin County, Xinyang, Henan Province

The middle and upper Huaihe River region contains abundant eastern Zhou archaeological remains. Among them, the Wanggang Cemetery-an elite Chu burial ground dated to the early Warring States period (475-338 BCE)-has yielded bronze vessels of significant archaeometallurgical value. This study employs metallographic microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), micro-X-ray fluorescence (µ-XRF), and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) to characterise seven bronze vessels from the Wanggang Cemetery. The results indicate that the assemblage includes both cast and hot-forged artefacts, all made from Cu-Sn-Pb ternary alloys. This reflects a relatively uniform alloying tradition but diversified forming techniques. Meanwhile, lead isotope data reveal interregional metal-resource sharing among the middle and upper Huaihe River region, the Nanyang Basin, and the Jianghan Plain during the early Warring States period. Furthermore, bronzes from different sites within the middle and upper Huaihe River region exhibit highly consistent lead isotope signatures. These patterns were likely enabled by the region's well-developed fluvial transport network and its strategic geopolitical status within the Chu state. Comparative lead isotope analysis of galena deposits in Chu and adjacent regions rules out southern Anhui, western/southern Hunan, and eastern Hubei as major lead sources, while pointing to western Henan and northern Jiangxi as the most probable supply areas. These findings provide new insights into bronze production, lead resource exploitation, and interregional material circulation within the Chu state.