Ryūkakuji Iwaya Kofun

Ryūkakuji Iwaya Kofun is a square burial mound in Sakae with steep stepped slopes on all sides. The structure rises to over 13 meters in height and stretches approximately 78 meters on each side, containing two horizontal stone chambers inside.

The mound was built as a burial structure in the late 7th century. The two stone chambers inside were constructed from a porous sandstone containing shell deposits from the local area.

The stone chamber shows how ancient people honored their dead and the effort they invested in burial practices. You can see today how carefully the chamber was constructed and what importance this place held for that society.

The site is outdoors and can be explored by visitors, with local information centers in Sakae providing directions. It helps to wear comfortable shoes since climbing and walking around the steep mound can be physically demanding.

This is the largest square burial mound from its period in Japan, surpassing even the tombs of imperial rulers. The fact that this structure belonged to a high-ranking official or local leader, not an emperor, makes it particularly interesting to archaeologists.

Location: Sakae

Inception: 7 century

Architectural style: square kofun

GPS coordinates: 35.82111,140.27722

Latest update: December 10, 2025 20:01