ABSTRACT
In the middle third century ce, giant keyhole-shaped (zenpō-kōen) mounded tombs, or kofun, appeared in the southeastern Nara Basin, and quickly spread across most regions of Japan, except for Hokkaido and the Ryūkyū Islands. The Hashihaka tumulus (278 meters in length, and 35 meters in height, with a circular rear mound 160 meters in diameter), located in Sakurai City, in the southeastern part of the Nara Basin, is considered to be the earliest keyhole-shaped tomb. This marks the beginning of the Kofun era, which lasted until the beginning of the seventh century.
