Abstract:The axial system of traditional Chinese cities and architecture is not only a reflflection of temporal and spatial concepts but also of the philosophy of yin and yang, the belief in Heaven, environmental geography, cosmic concepts, and ritual norms. From the Yuan to the Qing dynasty, the central urban axis of Beijing did not coincide with the true meridian but diverged from the meridian by more than two degrees. As the people of the past had the ability to measure the meridian accurately, this was a conscious choice made by them rooted in the regulations for building a mingtang (numinous hall), the belief in Heaven, and the idea to adapt architecture to the topography, next to other environmental considerations.