Acala is commonly shown as having either black or blue skin (the "Sādhanamālā" describes his color as being "like that of the "atasī" (flax) flower," which may be either yellow or blue), though he may be at times portrayed in other colors. In Tibet, for instance, a variant of the kneeling Acala depiction shows him as being white in hue "like sunrise on a snow mountain reflecting many rays of light". In Japan, some images may depict Acala sporting a red (赤不動, "Aka-Fudō") or yellow (黄不動, "Ki-Fudō") complexion. The most famous example of the "Aka-Fudō" portrayal is a painting kept at Myōō-in on Mount Kōya (Wakayama Prefecture) traditionally attributed to the Heian period Tendai monk Enchin. Legend claims that Enchin, inspired by a vision of Acala, painted the image using his own blood (thus explaining its red color), though recent analysis suggests that the image may have been actually created much later, during the Kamakura period. The "Ki-Fudō" image, enshrined in Mii-dera (Onjō-ji) at the foot of Mount Hiei in Shiga Prefecture, is meanwhile said to have been based on another vision that Enchin saw while practicing austerities in 838. The original "Ki-Fudō" is a 'hidden buddha' or "hibutsu" (秘仏, Buddhist images hidden from public view) traditionally only shown to esoteric masters ("ācārya"; 阿闍梨, "ajari") during initiation rites, though copies of it have been made. One such copy, made in the 12th century, is kept at Manshu-in in Kyoto.