A physician from the Jin Dynasty, a native of Shanyuan (present-day Sheng County, Zhejiang), skilled in medical arts and Buddhist teachings. According to the Shaoxing Prefecture Records, Yu once treated a difficult delivery during a journey using mutton soup and acupuncture, resulting in the swift delivery of the baby. Fan Xingzhun believes this to be the earliest record of the use of sheep membrane in our country. The Sui Records mention a one-volume work titled Discussions on Preparedness and Precautionary Measures by Yu, which has been lost.