01 / Onono-iwaya Kofun
The burial chamber's ceiling is 6.5m high --'the highest in Japan,' says the Agency for Cultural Affairs.

This keyhole-shaped tumulus is about 123m long. The main room of its corridor-style stone chamber (横穴式石室) measures 5.2m long, 3.0m wide and 6.5m high, a ceiling height the Agency for Cultural Affairs describes as the highest in Japan. The mound was once thought to be a round tumulus 39m long, but excavations from fiscal 2003 to 2008 showed it to be keyhole-shaped.
- Chamber ceiling: 6.5m high
- Length: about 123m
- Late Kofun period (late 6th century)