What are the records about "hairpin" in ancient books?
"The Book of Rites and the Moon Order" says: "The moon in summer is also, and the son of heaven drinks with rites and music." "Shuo Wen Jie Zi Zhu" says: "Qiang, triol is also." In other words, rice and distiller's yeast are fermented again by adding wine instead of water to improve the alcohol content. This wine is very popular because of its high alcohol content.