Oubosan Kofun (Tumulus)
Zentsuji City is home to around 400 large and small tumuli, making it a well-known town of ancient tumuli. Among them, the Arioka tumulus group is particularly noteworthy as it is believed to be the tumulus of chiefs from the same lineage.
This group is known as the Valley of the Kings in Zentsuji City and has been designated as a national historic site.
At the center of the Arioka tumulus group is the Oubosan tumulus, which is a 46-meter-long, front-recessed circular mound.
It is believed to have been constructed in the first half of the 6th century.
