The tumulus was designated a National Historic Site of Japan in 2002 with the area under protection expanded in 2003..[1] It was said to be the joint tomb of Empress Suiko and her son Prince Takeda before they were reburied in the Yamada Takatsuka Kofun the Isonagatani Kofun cluster.

[2] It was robbed before the modern period, and a number of the stones used in its construction, including the monolithic ceiling stone for the east burial chamber, which was repurposed as a water basin during the construction of Kashihara Shrine in the early Meiji period.

A hollowed-out house-shaped stone coffin made of tuff from Mount Aso was placed in the antechamber.

In the drainage ditch, gilt bronze ornamental metal fittings from horse harnesses and a crystal three-ringed ball hilt from an iron sword were found.

Sue ware was excavated..[2] The location and configuration of this tumulus correspond to an account in the Nihon Shoki, which stated that Empress Suiko was buried in the tomb of her son, Prince Takeda, in 628.