A group of about 150 tombs in Tajima, including the four large chambered tombs Kinrizuka, Tsukayama, Nishinooka and Komorizuka, smaller subgroups, and the earlier Dobayashi subgroup. A fiscal-2025 survey estimated Kinrizuka’s corridor chamber at about 15.1m long, among the largest in Hyogo.
Finds & research
The four large corridor chambers survive. Excavations identified Kinrizuka’s surrounding ditch and established from its ditch that Komorizuka was a round mound about 23m in diameter.
Two views on the occupant
Archaeological view
About 150 mounds extend for roughly 1.5km east–west and 1km north–south on the right bank of the Maruyama River in Oyabu, Yabu. The Dobayashi subgroup includes late-5th- to early-6th-century coffin burials; the four large chambered tombs are dated from the late 6th to mid-7th century, in the sequence Kinrizuka, Tsukayama, Nishinooka and Komorizuka. A fiscal-2025 excavation identified Kinrizuka’s surrounding ditch and revised its mound dimensions to about 40m north–south by 38.5m east–west; excavations in fiscal 1994–95 had established Komorizuka as a round mound about 23m in diameter.
Imperial Household Agency view
Not an Imperial Household Agency mausoleum. Of the four large tombs, Kinrizuka became a Hyogo Prefecture Historic Site in March 1986, while Tsukayama, Nishinooka and Komorizuka were designated in March 1988. The Nozuka and Dobayashi subgroups became municipal cultural properties in September 1979. The designations do not cover the entire group.
Field notes
Yabu City provides a group map and descriptions in its Oyabu Kofun Group brochure. Follow local signs for chamber access. The group pin marks the area near Kinrizuka.