Mikomori-san
Mikomori-san (みこもりさん) is a term that appears in Fatal Frame V.[1] Once a year, people in the Mikomori Region who lived around Mount Hikami would journey to the mountain to take water from it, which they called mikomori-san, and enshrine it at their houses. The water would only be used for special events, such as for a baby's first bath or washing a dead body in preparation for its burial. The custom arose from the belief that doing so would return their souls to the water from which it came.
According to an old woman from Mikomori Village, another use for this water came when rumbling came from the mountain. In her story, it was customary to submerge oneself or bathe in mikomori-san when Mount Hikami began to rumble, seemingly because rumbling from the mountain was considered a bad omen, and they thought that drenching themselves with purified water would protect them. They would stay inside their houses the entire time, and when it was over, sometimes young women would be called into the mountain, apparently spirited away.