The Underworld and the Purification Ritual
After Izanami died giving birth to the fire deity, Izanagi descended to Yomi (the underworld) to retrieve her. But she had already eaten the food of Yomi and could not return. When Izanagi broke his promise and looked upon her decayed form, he fled in horror. At Yomotsuhirasaka—the slope marking the boundary between the living and the dead—he sealed the entrance with a great boulder.
The exchange that followed encapsulates a profound Shinto philosophy of life and death: Izanami vowed to kill a thousand people daily; Izanagi countered that he would establish fifteen hundred birthing houses each day. Life perpetually overcomes death.
Back in the world of the living, Izanagi performed a purification ritual (misogi harai) in a river. As he washed his left eye, Amaterasu (the Sun Goddess) was born; from his right eye came Tsukuyomi (the Moon God); and from his nose emerged Susanoo (the Storm God). These three—the “Three Noble Children” (Mihashira no Uzu no Miko)—went on to govern the heavens, the night, and the seas.
This purification ritual is the mythological origin of the hand-washing (temizu) performed at every shrine entrance today.