This is a Shinto ritual that I had the chance to participate in at the Tsubaki Grand Shrine. It’s done in a grotto-like setting in the dark of night, with lit candles burning in spaces between the rocks of the surrounding wall. Men and women do this separately and the women wear a white kimono-like garment while the men wear this diaper-like garment. Exercises are performed about 30 minutes beforehand along with chanting. With the help of priests, you are escorted one by one over the rocks in the pool until you get to this larger center rock under the snowmelt waterfall. There you chant what they have taught you for about 20-30 seconds and then you are released and supposedly purified. No photos of this process were allowed so I grabbed a quick sketch. I had a cold at the time and was not able to participate, but it was an awesome experience nonetheless.
Watercolor and ink