In the coastal hills of Izumo, researchers have unearthed a Yayoi-period shrine containing a central pillar surrounded by eight polished copper mirrors. The mirrors were oriented to catch the first light of the rising sun during the summer solstice, reflecting the beams onto a central jade stone. This arrangement suggests a highly formalized Solar Greeting festival that predates many established Shinto traditions.
This discovery provides a tangible link to the mythological foundations of Japan, specifically the tales of the sun goddess Amaterasu. The shrine's design indicates that communal gatherings were held here to witness the solar reflection, reinforcing the sun's role as a primary focus of early Japanese seasonal festivals and cultural unity.