After the war, teacher Yoshio Sonoda (deceased) continued his pioneering excavation
work, focusing on the Chiamigaito ruins in Kawauchi-cho 3-chome.
The objects he uncovered and collected that were not entrusted to other institutions
are preserved here. The ruins are located on a riverbank at the confluence of the Watarase
and Yamada rivers; 3297 of the items excavated, including some large ear ornaments, have
been designated important national cultural assets.