The first-listed (No. I) satellite tomb of Daisen Kofun. A scallop-shaped mound, 65m long. The truncated front section of the scallop form is regarded as a burial type for powerful figures ranking just below full keyhole-mound status. Sakai City dates it to the middle of the 5th century, the World Heritage site to the first half. It lies south of Daisen's front section, on the projected axis of the great mound and with its own axis parallel to Daisen's outer moat, its front section facing west; the rear circle stands 7.7m high. The front section and moat were reconstructed from confirmation surveys made when the park was laid out. The rear circle is administered by the IHA, the front section and moat by Sakai City (designated a Sakai City Historic Site in 2017). Constituent monument of the "Mozu-Furuichi Kofun Group" UNESCO WHS (2019). The scallop-shaped mound form concentrates in the Mozu and Furuichi groups of the 5th century, documenting the diversification of burial mound forms in this period. Restricted from general entry as an IHA satellite tomb, but the scallop outline is visible from the outer roads of Daisen Park.
Finds & research
The internal burial facility remains unexcavated under IHA management. However, a confirmation survey in FY2011 identified the mound edge and the outer edge of the moat, with fukiishi (facing stones) and haniwa confirmed (Sakai City). Interior grave goods remain unknown. Exterior viewable from public paths.
Official status & archaeological view
Official status
Managed by the IHA as "Satellite Tomb No. I, detached parcel" (the first-listed satellite) of the Nintoku Mausoleum. The IHA catalogs satellite tombs using the Japanese iroha syllabary (i, ro, ha, ni, ho, he, to…); this is tomb "I" (the first). Managed as an appendage of the Daisen Kofun (Nintoku) imperial mausoleum. The front section and moat were designated a Sakai City Historic Site, the "Magodayuyama Kofun front section and moat", in 2017.
Attribution (jitei): the Imperial Household Agency's determination of whose tomb it manages — separate from heritage designation.
Archaeological view
It is classified as a "hotategai-kei" (scallop-shell-shaped) mound. This form is a variation of the keyhole mound in which the front section is drastically shortened, creating a shape resembling a scallop shell. 65m long, with a rear circle 46m across and 7.7m high built in two tiers, and a front section 26m wide and 2m high. Scallop-shaped mounds flourished in the Middle Kofun period (5th century) as a tomb type ranking just below the standard keyhole form.
Field notes
The official World Heritage site gives about a 5-minute walk northwest from JR Mozu Station (Hanwa Line). Sakai City lists it as within Daisen Park. The round rear mound is managed by the IHA and cannot be entered.