From periphery to borderland: Yelang metallurgy and Han imperial governance of Southwest China

The Bronze Age cultures of Southwest China were marked by remarkable diversity and vibrancy. As the Han Empire (202 BCE–220 CE) expanded into the region and established governance, indigenous polities gradually disintegrated. Existing research paradigms that interpret archaeological materials primarily through historical texts are limited in explanatory power. Studies on the interactions between the Han Empire and its southwestern periphery must now prioritize the cultural agency of indigenous groups. By integrating archaeometallurgical data with historical textual evidence, this study explores the subtle process by which the Han Empire gradually infiltrated Guizhou.

Metallurgical analyses indicate that western Guizhou, the core of the Yelang culture, experienced a technological evolution from unalloyed copper to tin bronze and then to lead-tin bronze between the 5th and 1st centuries BCE. Lead isotope data from Hezhang suggest four distinct lead sources. Copper and Type B lead were likely local to the Yunnan–Guizhou region. Type C lead may have come from northern China, and Type D appears to be a mixture of common local lead and highly radiogenic lead from northeastern Yunnan. Type A lead, matching isotopic signatures from Xiaoqinling in western Henan, was introduced into northwestern Guizhou under Han cultural influence.

These findings suggest that Han influence reached northwestern Guizhou before the mid-Western Han. Even prior to Emperor Wu's campaigns, Han artifacts, technologies, and mineral resources had already permeated the region. Resource exploitation drove Han expansion into the southwest, while both local and external forces shaped the integration of Yelang. Subjected to multifaceted cultural influences, Yelang underwent gradual transformation, accelerating the Sinicization process in the Guizhou region. In its early engagement with the Southwest, the Han empire adopted a low resistance strategy of infiltration and control rather than outright replacement. Through the gradual introduction of goods, technology, and raw materials, it steadily penetrated Guizhou, reflecting the power structure when the Han Empire initially encountered the highlands of Southwest China.