Reassessing the architectural configuration of Northern Song imperial tombs: Restraint and functionality reflected in the Upper Palace of Yongchang Mausoleum

Yongchang Mausoleum, the tomb of the founding ruler of the Northern Song dynasty, occupies a pivotal position in the development of Chinese imperial tomb architecture. This study reconstructs the above-ground architecture of its Upper Palace by integrating archaeological evidence with textual records and coeval parallels. Employing a systematic approach that progresses from abundant to scarce evidence and from macro-scale features to finer structural details, the study applies quantitative methods to infer construction units (chi) and estimate timber grades, while considering modular principles and traditional construction norms. The reconstruction reveals a coherent layout centered on the burial platform, with an axial sequence of ritual structures—including que towers and the Spirit Gate—reflecting Tang precedents. Architectural elements combined ceremonial, functional, and spatial roles, providing a template for later Song and Western Xia mausoleums. Notably, Yongchang exhibits relatively restrained dimensions in timber and platform scale, reflecting early Northern Song political and fiscal priorities, and illustrating a broader tradition of architectural frugality. This study deepens our understanding of Northern Song imperial tomb design, and its most robust findings may serve as references for future architectural-historical research and for presenting this heritage more accurately to the public.