The pit type consisted of a hole which was made from the surface of a tumulus called a Boko (a tunnel to put a coffin in), where a coffin was placed at the bottom, and filled with sand again.
竪穴系のものは、築造された墳丘の上から穴を掘り込み（墓坑　ぼこう）、その底に棺を据え付けて埋め戻したものである。