It is in the shadow of a 30-meter-high limestone outcrop, the center of the ruins extends from the north end to the southwest side of the rock wall.

Archaeological excavations have been conducted five times since 1970, with stratigraphic examination of over 14 layers indicated that it had been occupied from the early to late Jōmon period.

Artifacts were found in all layers, and included Jōmon pottery with fine ridge line designs, tongued points, arrowhead grinders, sharpeners, gravel implements, and seven stone slabs inscribed on chlorite schist.

A total of 28 sets of human remains were also found, notably a female human hipbone with a deer-antler javelin stuck in it, believed to have been part of a posthumous ritual, as well as a female statue carved into a stone using a sharp flake stone tool, which may have been a ritual object.

The same soil layer also unearthed the world's oldest piece of earthenware at the time of its discovery, radiocarbon dated to approximately 14,500 years ago.