Taiyi Pool, also known as Taiyi Spring, is the highest fissure spring in Wangwu Mountain. In philosophy, Taiyi refers to the origin and noumenon of all things in the universe. Its water source is underground water filtered by layers of rocks, which is blocked by the bottom shale aquifuge and gathers into a pool in the butterfly depression. The ancients regarded it as the source of one of the four blasphemies, and Xu Jingzong was quoted in The Book of New Tang Dynasty: "blasphemy is the only way to speak, and you can only go to the sea because of the surplus water." The economic undercurrent is repeated, although the shape is subtle, it is unique and respectful. ” In addition, it is recorded in Recalling the Past that "the water comes out of the king's house, and its source is inexhaustible. The spring is boiling, and the ground is light. "The record confirms this cognition.