A mid-sized keyhole mound in the Mozu group, 106.4m long with a front section 10.6m high, built in the late 5th century. It carries no Imperial Household Agency designation and is managed by Sakai City as part of the National Historic Site Mozu Kofun Group. It lies about 160m south of the south-east corner of Daisen Kofun, between Daisen and Gobyoyama, with its front section facing west. Like Nisanzai Kofun, its broad, high front section displays a later trend in mound design. Ground-penetrating radar indicates that the burial facility is a pit-style stone chamber. It is a constituent monument of the Mozu-Furuichi Kofun Group World Heritage Site, inscribed in 2019.
Finds & research
Ground-penetrating radar has identified the burial facility as a pit-style stone chamber; it has not been excavated. Cylindrical and figural haniwa have been recovered from the mound and the moat. A moat surrounds the mound and is preserved underground.
Two views on the occupant
Archaeological view
A keyhole mound 106.4m long with a front section 10.6m high, built in two tiers in the late Middle Kofun period (second half of the 5th century). It stands about 160m south of the south-east corner of Daisen Kofun with its front section facing west, and has a projection on the south side of the waist only. Radar survey has identified the burial facility as a pit-style stone chamber. The IHA has made no satellite designation, and the occupant is unknown. The name "Nagatsuka" (Long Mound) may refer to the elongated shape of the mound.
Imperial Household Agency view
Not designated by the IHA. Preserved and managed by the Sakai City Board of Education. Not listed in the IHA register. Protected by Sakai City as part of the National Historic Site "Mozu Kofun Group"; archaeological excavation is permitted.