In the 3rd - 7th century AD, Japanese tombs looked like tomuli - like a mound in the shape of a keyhole. These ancient heaps are called kofun 古墳, "ancient grave." They gave the name of that period in the Japanese history as well - the Kofun period.
An aerial view:
The terracotta figures are called haniwa and delimit the sacred areas.
The funeral chamber is beneath the round area of the kofun.
One kofun can be up to 400 m long.
Buddhism was introduced to Japan in the late 6th century, and kofun started to disappear.
Some children chasing butterflies nearby: