Built in: Late 4th century.
Size: 150m long, 99m deamiter, 13m tall.
Hirui Otsuka Kofun is one of the Mausoleum located in Ogaki, Gifu Prefecture. In this area, there are many Kofun that explains this place is used to be the large tribe with a powerful King. This
Over 4,000 precious balls found at this Kofun. At the inside of the chamber, 40 relics are found including iron swords.
This Kofun was used to be surrounded by 1,500 Haniwa.