The Kifudo-Myo-o (Yellow Fudo, Acalanatha) at Onjo-ji is the most iconographically unique of the numerous images of the Fudo-Myo-o produced since the Heian Period. Heretofore, it has been held that, in keeping with the account in the Enchinden of 902, the work was made according to an inspiration the Tendai priest Enchin (814-891) had while sitting in meditation, before he set sail for China. This treatise proposes that, contrary to this traditional view, Enchin drew on some definite iconographic sources in conceiving this work. Specifically, various features of the Fudo-Myo-o have been based not only on the Ninno-gyo Goho Shosonzo brought to Japan by Kukai, as has previously been pointed out, but also on the Taizo Zuzo brought by Enchin himself. In addition, the depiction of a yellow Fudo-Myo-o standing in an empty void corresponds with what is written in the Dainichi-kyosho translated by Zenmui. Probably painted sometime after Enchin's return to Japan in 858, this work represents an epochal development in the Mikkyo art of the Tendai sect in Japan.