Yaobikuni (⼋八百⽐比丘尼) is the name of a legendary nun who lived for eight- hundred years but retained the youthful appearance of a young woman throughout her whole life. Her perpetual youth and beauty were attained by accidentally eating the flesh of a Ningyo (fish-like creature) - which is said to grant eternal life. Her story is found over and over again in almost every region of Japan.
Long ago, a fisherman discovered a strange creature when he pulled up his nets. It was the largest fish he had ever caught in all of his years of fishing, and it had a human face. He told everyone he knew about the fabulous and strange fish he had caught, and invited them to dinner to taste it. During the meal, one of his guests snuck off into the kitchen to sneak a peek at this fish which everyone had all heard so much about. The guest recognised that it wasn’t a fish, but a Ningyo. It was well known that Ningyo flesh bestowed eternal life and youth on whomever ate it. He quietly warned the others what it was. Despite the promise of eternal life, the guests felt strange about eating the flesh of a yōkai, so they only pretended to eat the meat, secretly wrapping it up and hiding it in their sleeves to discard on the way home.
One of the guests, however, had gotten drunk and forgot to throw away his meat. At home, he absent-mindedly gave the leftovers to his teenage daughter. The next morning, he remembered what he had done and was filled with dread. He was sure that his daughter would be poisoned or cursed for eating yōkai meat. Days passed, but she showed no signs of distress. As she appeared alright, the man never bothered to say anything about the Ningyo to his daughter. Soon the matter was forgotten entirely. Many years passed, but the young girl never seemed to age a day. She got married. Her father grew old and died. Eventually, so did her husband. But no matter how many years passed, the girl remained as youthful and beautiful as she did in her teens. Everybody she cared for grew old and died while she never aged. She became sad and lonely, and eventually she joined a temple and became a nun. She left her hometown to travel the country, planting trees and helping people wherever she went.
After hundreds of years, Yaobikuni grew weary of the world. She retired in Wakasa Province, and took up residence in a cave. There she prayed day and night to be free of her curse. She never moved from the cave, and eventually she had sat for so long that she turned into stone. It is said that in one of the caves around Wakasa, there stands a stone that looks just like a beautiful, young woman.