Wangwu Mountain corresponds to the north celestial pole. This well is located in Tianji position in the Plaza, hence the name Tianji well. For thousands of years, Tianji well has been dry for a long time. Tao Te Ching said: "Good is like water, and all things in water conservancy are not disputed". Jishui is the best realm of "water" in the world, with its flat springs, limpidity, hiding and appearing, crossing the river without turbidity, benefiting and harmless. According to legend, Yellow Emperor, Lao Zi, Sun Simiao, and Qiu Chuji all used this well to prevent and treat folk plague diseases.