A large keyhole mound (203m, 4th largest in the Mozu group) within Daisen Park, Sakai City. The three-tiered mound with triple moats is an imposing monument. Access to the mound itself is restricted as an IHA reference site. Located just 500m northeast of Daisen Kofun, the two giant mounds together form the dominant landscape of the Mozu plateau. One of the 49 constituent monuments of the "Mozu-Furuichi Kofun Group" UNESCO WHS (2019). The name "Gobyoyama" derives from gobyo (sacred mausoleum), indicating early recognition of its funerary importance. The IHA's reference-site designation associating it with Emperor Ojin draws a parallel with Konda Gobyoyama Kofun (425m) in the Furuichi group.
Finds & research
No excavation permitted under IHA mausoleum regulations. Internal structure and grave goods remain unknown. Exterior viewable from public paths.
Two views on the occupant
Archaeological view
The occupant is archaeologically unknown. 203m long (3rd largest in the Mozu group after Daisen, Kamiishizu Misanzai, and Haji Nisanzai), with three-tiered construction. Dated to the early 5th century based on haniwa typology. Located immediately northeast of Daisen Kofun, it is presumed to have a close relationship with that mound. Some identify it as the tomb of a figure connected to Emperor Ojin, paralleling the Konda Gobyoyama Kofun in the Furuichi group, but archaeological evidence is lacking.
Imperial Household Agency view
Designated by the IHA as a "Ryobo Sankochi" (imperial mausoleum reference site) associated with Emperor Ojin. This lower-tier designation indicates a site possibly—but not definitively—related to an imperial burial. Administered by the IHA Shoryobu bureau. As it lies within Daisen Park, it is visible to park visitors, though access to the mound itself is restricted.
Field notes
The Daisen Park promenade allows close observation of both the front and rear sections. It can be conveniently combined with a visit to the Sakai City Museum (in the park) and the Daisen Kofun exterior walk. From the park's grass meadow, the rear circle of Gobyoyama is visible as a green hill to the south.