In considering the vital role played by imperial rites in claiming political legitimacy and maintaining social stability, Chinese emperors endeavored to present themselves as the perfect model for their subjects in terms of ritual performance. Focusing on a Northern Song (960–1127) ritual debate over the placement of imperial ancestors’ spirit tablets and ancestral chambers, especially that of the Primal Ancestor, this study aims to contribute to a better understanding of discussions on ancestral rituals and how they were intensified during the implementation of Wang Anshi’s New Policies. More importantly, this study reveals the differences between Song scholar-officials’ political positions and intellectual interests, thus providing a new interpretation of Song factionalism from the perspective of ritual politics.