Tru Bieu gateways of Hue’s village communal houses in Vietnam: morphology, decorative grammar, and vernacular threshold typology

This article examines the Tru Bieu, the pillar gateways of village communal houses (Dinh) in Hue, Vietnam, as a distinctive vernacular threshold type within the broader East Asian architectural landscape. Based on field surveys of 64 Dinh (including 58 four-pillar gateways), the study integrates morphometric measurement, statistical and overlay analyses, decorative motif classification, and semi-structured interviews with nine master artisans. The findings demonstrate a recurrent yet adaptable proportional module where central pillars consistently exceed the height of lateral ones by approximately 7% (h1/h2 = 1.075), and lateral spans are closely calibrated to the main span (B = 0.9A), and elevations converge on a tripartite base:body:capital ratio of roughly 1:4:3. Quantitative matrices of motif frequency further reveal a rule-based pattern of decorative organization that differentiates axial from peripheral roles, with dragon imagery and paired inscriptions concentrated on the central Tru Bieu and floral or plain fields prevailing on lateral pillars. Artisan testimonies confirm that these rules are transmitted through embodied craft knowledge rather than written prescriptions. Comparative discussion with Vietnamese regional variants and Chinese Paifang/Japanese Torii clarifies the typological autonomy of Hue’s roofless and communally oriented gateway, and provides an evidence-based framework for documentation, conservation, and contemporary design reference.