Vernacular Architectural Knowledge in Historic Fortified Settlements of the Middle Qinhe River Basin

Historic fortified settlements constitute a distinctive component of the traditional settlement heritage of the Qinhe River Basin, where they historically combined defensive, residential, clan-governance, commercial, transport, and resource-use functions. Previous research has generated substantial understanding of their historical development, spatial morphology, environmental adaptation, and conservation. Less clear, however, is the intermediate process through which vernacular architectural knowledge can be identified from heterogeneous evidence, tacit social experience can be anchored to specific spatial carriers, and these findings can be translated into site-specific conservation actions. Focusing on the middle Qinhe River Basin, this study establishes a regional background inventory of 66 sites, selects 19 settlements with comparable spatial data for geographic information system (GIS) analysis, and conducts an in-depth comparison of five information-rich and typologically distinct cases: Guoyu Ancient City, Xiangyu Ancient Fortress, Huangcheng Xiangfu, Diji City, and Douzhuang Village. Documentary analysis, field investigation, spatial analysis, multi-source corroboration, hierarchical coding, spatial anchoring, and relational visualization are combined in an identification-comparison-interpretation framework for vernacular architectural knowledge. The results organize this knowledge into two interrelated layers. Explicit architectural knowledge comprises environmental siting, defensive space, building construction, and spatial organization; tacit architectural knowledge comprises clan organization, belief and ritual, craft practice, trade and transport, resources and livelihoods, collective defense, and local memory. Although the five cases share broadly similar regional settings and historical security pressures, they do not converge on a single defensive morphology. Instead, they show different knowledge relationships, including village-fort integration, vertically coordinated riverfront defense, the integration of official residence, clan organization, and defense, the coupling of resource-based construction with water-land access control, and layered defense through inner and outer enclosures. Tacit knowledge, moreover, is not treated as something that can be directly “extracted” through hierarchical coding; it is interpreted only after documentary, secondary oral-history/local-memory, field, and spatial evidence have been cross-checked and linked to identifiable spatial carriers or behavioral processes. These findings suggest that conservation should move beyond the repair of individual structures toward maintaining relationships among spatial carriers, behavioral processes, social relations, and local memory through case-specific combinations of material repair, interpretive routes, community participation, and routine monitoring.