Although initially, these techniques were practised by priests from overseas, especially from China and Korea, who had settled in Japan and were proficient at reading and writing Kanbun (Chinese classical literature), the later 7th century saw the appearance of Ommyo-ji as there was a need for laymen with the techniques, not priests, to serve the Imperial court.
このような技術は、当初はおもに漢文の読み書きに通じた渡来人の僧によって担われていたが、やがて朝廷に奉仕する必要から俗人が行うことが必要となり、7世紀後半頃から陰陽師があらわれ始めた。