The Shinjō-ryūō mounded tomb No.1 is a scallop shell-shaped mound tomb located in Shinjō-chō, Shōbara City, Hiroshima Prefecture. In March 2007, as part of “Field Practice in Archaeology C” for the sixteenth annual class of archaeology majors at the Hiroshima University School of Letters, we conducted a topographic survey of this mound with the aim of creating a detailed survey map and clarifying its historical significance. The results of this survey indicated that the Shinzō-ryūō mounded tomb No.1 is a scallop shell-shaped mounded tomb of the Kofun period with 51.9m in length. In addition, according to the possibility that the mound shape is similar to that of the Maruyama-jinja mounded tomb No.1 and the change of the surface shape of the rectangular part of scallop shell-shaped mounded tombs in Hiroshima Prefecture, we draw the conclusion that the Shinjōryūō mounded tomb No.1 was constructed around the end of the 4th century to the early 5th century AD. As a result, the Shinjō-ryūō mounded tomb No.1 is the oldest among the scallop shell-shaped mounded tombs of the fifth century in the vicinity of the cities of Miyoshi and Shōbara in the northern part of Hiroshima Prefecture
