Tajima's largest keyhole mound, on the left bank of the Maruyama River in Asago City. Renowned as Japan's richest source of waterbird haniwa, thought to express beliefs about the watery otherworld. As railway and highway cut the mound, the visit centers on the finds at the Hyogo Prefectural Museum of Archaeology.
Finds & research
23–30 waterbird haniwa (the most from any kofun; 14 are ICPs), cylindrical and figural haniwa, and umbrella-shaped wooden objects. Burial unexcavated.
Two views on the occupant
Archaeological view
A keyhole mound ~135m long (measurements range 134.5–136m) — the largest in Tajima and fourth in Hyogo. Built in the early 5th century; the burial is unexcavated (a chest-style sarcophagus is presumed). Its moat yielded the largest number of waterbird-shaped haniwa from any single kofun in Japan — 23 to 30 individuals depending on the count, 14 of them Important Cultural Properties. The mound has been cut by the Meiji-era San'in Line and the Route 9 bypass.
Imperial Household Agency view
Not designated by the IHA. Hyogo Prefectural Historic Site (2013); the excavated artifacts were designated Important Cultural Properties in 2019.
Field notes
About 5 min by car from JR Wadayama Station, but the site itself is unmaintained and bisected by rail and road. See the waterbird haniwa at the Hyogo Prefectural Museum of Archaeology. Pairs well with Chasuriyama Kofun (id:588) for tracing Tajima's chieftains.