It is said that Dokyo once cured Retired Empress Koken by using a mystical rites of Sukuyo (an esoteric Buddhism astrology based on the Sutra of constellations and planets, and an astrological doctrine of which was introduced from India), and since then, the Empress and Dokyo had maintained a close relationship.
道鏡は孝謙上皇の病を宿曜秘法を用いて治療し、それ以来、孝謙上皇と道鏡は密接な関係があったとされる。