| Location | Sakai, Osaka |
|---|---|
| Shape | Keyhole-shaped mound |
| Mound length | 300 m |
| Period | Late 5th century |
| World Heritage | Mozu-Furuichi Kofun Group (UNESCO) |
300m long (7th nationally, 3rd in Mozu group). 3-tiered construction rising to about 23m at the rear circle. As a reference site (sankochi) rather than a confirmed mausoleum, it has permitted more academic investigation than the main designated tombs. Joint surveys by Sakai City and the IHA (2004, 2010) revealed detailed mound structure. It stands at the eastern edge of the Mozu group, now within Sakai City's Naka ward.Constituent monument of the "Mozu-Furuichi Kofun Group" UNESCO World Heritage Site (2019). The "reference site" (sankochi) designation differs from a confirmed mausoleum (ryo) in that the IHA has determined there is a possibility of imperial connection without certainty. This allows slightly more academic access, making Haji Nisanzai an important case study for understanding Mozu group mound construction methods.
Joint IHA/Sakai City surveys (2004, 2010) confirmed three-tier construction, stone paving (fukiishi), and haniwa rows at the waist section of the rear circle. As a "reference site" (sankochi), this mound has permitted more investigation than typical designated mausolea, making it an exceptional source of archaeological data within the Mozu group. Cylindrical and figural haniwa fragments have been recovered; burial facility and grave goods remain uninvestigated.