Introduction to Xu Shu Cave: According to legend, Xu Shu, Liu Bei’s military advisor during the Three Kingdoms period, came to Mount Ai after returning to seclusion. Seeing the beautiful scenery here, he dug a hole in the cave and settled in the cave to cultivate himself. From then on, he left behind the words "Xu Shu is not separated from Ai" and "Xu Shu Cave". s legend.