Abstract for “The Marginalization of the Esoteric Buddhist Medical Astrology”

By the time Buddhism reached Japan in the 9^th century, the Hindu astrology had already been incorporated into its teachings, and its practice was consequently spread as an esoteric form of understanding the religion by such Buddhist pioneers in Japan as Kukai and Saicho. Thus transmitted, the peculiar and localized form of the Hindu astrology came to be known as Sukuyoudou (宿曜道), or the way of telling future events by means of looking at the lunar mansions and the astrological signs. This tradition, however, dwindled rather quickly, and by the 12^th century, its rival theory of On’myoudou (陰陽道) that based its system on the Ying-Yang Five Activity (陰陽五行説) prevailed. On’myoudou, too, would face the defeat against the Western science and medicine in the Edo period. What interests me, however, is not the eventual defeat of the Japanese esoteric astrology in the advancement of modern science, but the ways in which these seemingly unscientific theories such as astrology were able to account for the causes of illness and provide cure for them up to their replacement with the Western science. As in the West, astrology was not only a means to predict future events, but also preeminently a medical practice on which people depended for their health and wellbeing. My aim in this paper is to explain the mechanics of such system as introduced by esoteric Buddhist teachings, and offer an account for why such astrology had to give away. In doing so, I will specifically focus on its medical aspect, calling it a practical astrology, rather than its predictive aspect normally attributed to such a discipline. I hope to show that the esoteric Buddhist medical astrology did contribute significantly to the later theories that replaced it, and hence was essential to the advancement of modern medicine. However, its compatibility with On’myoudou and the latter’s broader applicability made it inevitable that Sukuyoudou got subsumed under it, still managing to survive being marginalized, and Sukuyoudou continued to exert influences in our everyday life even after centuries of its marginalization in history of medicine.