The largest source of obsidian in Japan is scattered along the Yubetsu River as the “Shirataki Site Group.
The stone tools are called “Yubetsu technique” and seem to have had a close relationship with the whole area of Northeast Asia.
More than 1,900 pieces of obsidian stone tools and other artifacts are displayed as national treasures at the Engaru Town Buried Cultural Properties Center in Shirataki.

Engaru Town Buried Cultural Properties Center.

Engaru Town Buried Cultural Properties Center.

National Historic Site Shirataki Ruins.

The Yubetsu River flows near the Shirataki Ruins.