How did Daoism and yinyang philosophy affect early Japanese religious and philosophical ideas?

Daoism and yinyang philosophy (known in Japan as in-yō) significantly shaped early Japanese religious and philosophical thought through their integration into court life, folk beliefs, and established religions like Shintō and Buddhism.123

Rather than being implanted as a formal, unified religion, Daoist practices were adopted selectively. By the 7th century, the Japanese court established the On-myō-ryō (Bureau of On-myō), a government department tasked with divination and regulating the calendar based on yinyang principles to maintain harmony between the social and cosmic orders. This influence persisted through the ommyō-ji (masters of yin and yang), who utilized the I Ching and Chinese astrology to guide court life, including the observance of directional taboos.213

Daoism also deeply influenced Japanese spiritual life through:
* Folk Beliefs: Practices such as the Kōshin vigil and various magical arts, including exorcisms and the use of mirrors or charms, became widespread.12
* Asceticism: Techniques for longevity and spiritual power were adopted by yamabushi and practitioners of Shingon and Tendai Buddhism.2
* Religious Synthesis: The blending of traditions was a hallmark of Japanese history, where Daoist and yinyang concepts merged with indigenous kami worship and Buddhist thought.24