In March 1951, a junior high school student called Hiroshi Takizawa (瀧澤 浩, Takizawa Hiroshi) (who would later become an archaeologist) passing through the area found obsidian stone tools and clusters of pebbles on a cross-sectional part of a road that cut through a hill called Osedo-yama (オセド山, Osedo yama).

A joint excavation was conducted by Meiji University and Musashino Museum in July of the same year.

This was the second survey on the Paleolithic Age in Japan after a study of the Iwajuku archaeological site in Gunma Prefecture.

It became clear that Paleolithic culture, which is older than that from the Jōmon period, had spread universally in Japan.

In addition, the knife-shaped stoneware excavated in this survey had a very distinctive form and was named a Moro knife (茂呂型ナイフ形石器, Moro-gata naifu-gata sekki).