~45m circular mound (terminal kofun period) in Tenjin, Nagaokakyo City — part of the National Historic Site "Otokuni Kofun Group." The final chieftain's tomb in the Otokuni Kofun Group, housing one of the largest horizontal stone chambers in Kyoto Prefecture. Developed as Imazato Otsuka Kofun Park; the megalithic stone chamber is open to view. Tomb of a magnate who controlled the Otokuni region in the early 7th century.
Current circular mound ~45m dia., 6.5m high (possible keyhole shape discussed). Early 7th century. Houses the largest horizontal stone chamber in the Otokuni region (burial chamber 5.5m+ long, 3m wide, 3.6m high) — third largest in Kyoto Prefecture after Hebizuka and Narabigaoka No.1. Surrounded by a shield-shaped moat (~18m wide). The final-phase chieftain's tomb of the Otokuni Kofun Group.
Imperial Household Agency view
Not designated by the IHA. Designated as part of the National Historic Site "Otokuni Kofun Group" in 2016 (Heisei 28). Located at Tenjin 5-chome, Nagaokakyo City. Developed as Imazato Otsuka Kofun Park.
Field notes
About 10 min walk from Hankyu Kyoto Line "Nagaokaten-jin" Station. Open as Imazato Otsuka Kofun Park (free). A rare opportunity to view the megalithic stone chamber interior up close. Recommended combined with Igenoyama Kofun (id:283).