Introduction to Kaogong Spring: Kaogong Spring was originally called the Good and Evil Spring. It is said that the spring water can cure all diseases and distinguish good from evil. As long as you stand by the spring, the image of the good will be clear and the image of the evil will be blurred. Li Chen, Emperor Xuanzong of the Tang Dynasty, issued an edict stipulating that local county officials should lead civil and military officials to Puli Temple to worship on the birthday of Buddha on April 8 every year. In order to expand the influence of Buddhism and rectify official customs and people's customs, Li Chen changed the name of the "Good and Evil Spring" to "Kaogong Spring" and stipulated that when officials made pilgrimages, they should take pictures by the spring so that the gentry and the common people could examine the officials' merits and demerits.