In ancient times, the son-in-law was used to refer to the son-in-law. After the ancients married their daughter who had been raised for many years, they often felt some loss and sadness, but they did not have opinions on their son-in-law, but had high expectations for them. They often called them their own Chenglong express son-in-law.
It is said that Nongyu, the daughter of Duke mu of Qin, was very intelligent and beautiful and liked music. Therefore, Duke mu of Qin asked him to carve a jade Sheng into a piece of beautiful jade and give it to his daughter. Therefore, Nongyu often played Sheng on the pavilion. Once her Sheng voice inadvertently attracted the chorus of Xiao Shi, a master of Huashan flute. Nongyu was very impressed with the sound of the flute, so he asked his father Qin Mugong to find the person who played the flute.
Duke mu of Qin immediately sent a large team to Huashan to find Xiao Shi. Seeing that Xiao Shi was handsome and elegant, and his flute playing skills were unmatched, Duke mu of Qin was very happy and asked his daughter to marry him. Later, Nongyu and Xiao Shi lived in seclusion in Huashan. They often played flute and Sheng on the top of the mountain. More than 10 years later, their ensemble even attracted Phoenix and dragon. The couple flew away in Phoenix and dragon. Since then, people called Qin Mugong's son-in-law Chenglong express son-in-law.