Navigating intra-regional unevenness in China: engaging secondary cities towards coordinated mega-regionalization

The mega-regional unevenness, namely the development gap between cores and smaller cities, has increasingly become a key obstacle for inter-city coordination in China. Scholars tend to focus more on the leading role of the cores in responding to this problem. When the smaller cities are mentioned, their endogenous characteristics and weaknesses are often highlighted, rather than being valued as important nodes embedded in the regional network and the inter-city relations. This paper conceptualizes these smaller players in mega-regional system as “secondary cities” to emphasize their interconnectedness to the cores and embeddedness in the inter-city relations. Based on this, we firstly examine the (trans)formation trends of the core-secondary relations in Chinese mega-regionalization. In this way, we focus on the role of secondary cities by exploring the functional and political positioning in the dynamic regional system. Building on such conceptualization of secondary cities, we construct an indicator system to measure changes of core-secondary unevenness from 2006 to 2023. We find that although mega-regionalization aims to rebalance inter-city relations, secondary cities are still facing challenges of polarization and peripheralization. Finally, we conduct a clustering analysis based on the differences between core and secondary cities regarding economic structure, aiming to explore the differentiated vulnerabilities of various types of secondary cities when confronted with polarization and peripheralization. This paper expands the theoretical scope of secondary cities to provide an innovative analytical perspective for understanding the mega-regional unevenness problems in China. Meanwhile, we also emphasize the potential and value of core-secondary relations in addressing the challenges of secondary cities with the expectation of more targeted policy and planning actions.