[3] 63 bronze objects have been found there from the middle Yayoi period,[4] alongside jadeite magatama.
It was discovered beneath a paddy field near the dolmen sites in Morita and Setoguchi.
An excavation in 1966 uncovered the long capstone of this dolmen along with significant artifacts such as large urns, jewelry, and bronze weapons.
AMS dating attributed the grains to the site's Yusu 1 period at end of the 9th century BC, which coincides with the rise of the Yayoi culture.
[6] Research by Nobuyuki Kamijo indicated that rice grains from the early Yayoi period at the Ukikunden site were varied in size, tending to be smaller.
Later in the early Yayoi period, rice had changed its form, resulting in a more consistent, rounder, and medium-sized grain.
[6] The Ukikunden site provides insight into burial customs from the Middle to Late Yayoi period.