The origin of matobi (a large bonfire for welcoming ancestors) was people burning straw in front of graves at Haru Higan, a Buddhist ritual at the vernal equinox/spring equinox for the repose of their ancestor’s souls. Matobi is said to be a magical welcoming fire that acts as a sign post for the spirits of the ancestors to gather.
Men hurry naked to the shrine in the pitch blackness of night during the coldest period of the year relying only on the moon for light. They purify themselves with water and then head towards the shrine to pay homage at midnight in front of everyone in their fundoshi loincloth.
This is a hot spring for day trips surrounded by the rich nature here and it has a real sense of seclusion. The smell of sulfur lingers in the air of this spring which has been loved as a therapeutic hot spring from long ago.