A 425m-long keyhole mound, the second longest in Japan and reportedly the largest by mound volume. The three-tiered mound has its front section facing north, and the rear circle rises 36m. Projections stand on both sides of the waist, and a square earthen platform occupies the summit of the front section. Two moats and an outer embankment surround it. The sharp bend in the inner moat on the east is interpreted as avoiding the earlier Futatsuzuka Kofun. The Agency for Cultural Affairs notes that the collapse of the north-west side of the front section is now widely attributed to an earthquake. The Imperial Household Agency administers it as the mausoleum of Emperor Ojin. It is a constituent monument of the Mozu-Furuichi Kofun Group World Heritage Site, inscribed in 2019.
Finds & research
A pit-style stone chamber recorded on the summit of the front section may lie within the square earthen platform. Cylindrical and figural haniwa have been recovered from the mound and moats, including many water-bird figures. The number of cylindrical haniwa that stood on the mound is estimated at more than 20,000 by the Agency for Cultural Affairs and more than 18,000 by the official World Heritage site. Clay objects shaped as fish, whales and octopuses have also been found.
Official status & archaeological view
Official status
The IHA lists its official form as zenpo-koen (keyhole). Officially designated "Ega-no-Mofushi-no-Oka-no-Misasagi" (Mausoleum of Emperor Ojin) by the IHA's Shoryobu bureau. Parts of the outer moat and outer bank, lying outside the mound, inner moat and inner bank managed by the IHA, were designated a National Historic Site, the "Ojin-tenno-ryo Kofun outer moat and outer bank", in 1978 (with later additions), and since 2001 they have formed part of the National Historic Site "Furuichi Kofun Group".
Attribution (jitei): the Imperial Household Agency's determination of whose tomb it manages — separate from heritage designation.
Archaeological view
Occupant archaeologically unknown. At 425m it is the 2nd longest mound in Japan, but first by the volume of the mound itself (Agency for Cultural Affairs). Dated to the middle of the Middle Kofun period (first half of the 5th century). Until the Meiji era a hexagonal hall stood on the rear circle as the inner sanctuary of Konda Hachimangu, the shrine immediately to the south. The adjacent Kondamaruyama Kofun is the reputed source of the gilt-bronze horse trappings, now National Treasures, said to have come to light in 1848. A Fujiidera City column, noting that there is still no settled view on which emperors the five kings of Wa correspond to, compares the construction order of the great mounds with the kings' dates and suggests that this mound is the tomb of the ruler who preceded San, the first of the five kings.
Field notes
A green corridor links the mound to Konda Hachimangu shrine, which adjoins it to the south, creating a distinctive landscape in which mound and shrine form a single whole. The official World Heritage site gives about a 16-minute walk southwest from Kintetsu Hajinosato Station (Minami-Osaka Line). The mausoleum is at 6-chome Konda, Habikino, Osaka. Per the IHA, it is about a 17-minute walk from Kintetsu Hajinosato or Domyoji Station, and worship is generally possible year-round from 8:30 to 17:00. The goryoin (mausoleum seal) is kept at the Furuichi Mausolea Office in Habikino, Osaka, where visitors can use it free of charge (reception 8:30–17:00; staff may be unavailable on weekends, holidays, 29 Dec–3 Jan and some other days).