The Miyoshi Basin is known nationwide as one of the places with the largest
number of kofun (ancient burial mounds) clustered in the area. There are about
3,000 of them there. The Jorakuji and Nanatsuzuka Kofun Groups are the
major ones in the Miyoshi Basin. They are designated as national historic sites
and placed under protection. The area of some 30 hectares centered around the
kofun groups is also developed as Miyoshi Fudoki no Oka.
 The Jorakuji Kofun Group has some large circular and scallop-shaped
mounds in its center, each of which is accompanied by smaller circular and
square mounds. The Nanatsuzuka Kofun Group consists of large circular,
keyhole-shaped and scallop-shaped mounds, surrounded by smaller circular
mounds and square mounds. The majority of the mounds were constructed in
the 5th to 6th centuries.
 Fudoki no Oka can be called an outdoor museum of history. The prefectural
museum of history and folklore exhibits materials on the history, folklore and
archeology of the Chugoku Mountain region. This park also has a hall with a
permanent museum of folklore materials; the old residence of the Shinno
family, which is designated as an important cultural property of Japan;
Shinotsuhara 3rd Kofun, which has an ashlar masonry chamber; a restored
ancient residence and a traditional iron furnace. In Hiroshima Prefecture, this is
the only open-air park that currently features historical sites.