Ba'an, there is Ba River in the east of Chang'an City, and there is a bridge on the water called Ba Bridge. When bidding farewell, people often break up willows here and give each other gifts. Li Bai's "Recalling Qin'e" has the sentence "The willows will turn green every year, and Baling is sad to say goodbye", and Luo Yin's "Send Jinshi Zang Xi back to Chizhou" says: "The willows climb the banks of Ba to cover their sleeves, and the water recalls Chiyang Lu with full heart." "Zhangtai and Ba'an are later used to refer to Liu.
Because the ancients also broke willows to express farewell.