In the late Heian period (794-1185), it was widely believed that burying sutras in the earth would preserve them for future ages. These relics, stuffed in a rare cast iron sutra container, were excavated from a sutra mound in the city of Miki, Hyôgo Prefecture. (The sutra container itself is presently undergoing restoration.) The outer container is gray ceramic with a round lid. The relics were accompanied by a Chinese Huzhou mirror of the Song period (960-1279).