A ningjo (Japanese: 人魚), a popular figure in Japanese folklore, is a Yokai. The name means fish-man, mermaid, mermaid.
The latter name can be misleading, as both their appearance and their nature are very different from the mermaid image that is familiar and common in Western culture.
Like their western relatives, they live a water-bound life, believed to live in seas and oceans.
In classical ningjo depictions, fish-like rather than human-like features predominate, but from the Edo period onwards, the Western mermaid image also became more prevalent, leading to a 'beautification' of the Japanese mermaids.
In the original Japanese depictions, however, they are depicted as fish-tailed, shiny, golden-scaled, hideous, deformed creatures with the features of both carp and monkey.
Their upper bodies are mostly human, and their hands end in long, bony fingers and sharp claws. Their stature can range from child-sized to the size of a seal.
One of the best-known ningjo legends is Jao Bikuni (Japanese: 八百比丘尼 "800-year-old priestess") or Happjaku Bikuni, the story of a fisherman from Wakasa Prefecture who one day finds an unusual catch.
In his long career, he has never seen a fish like it, so he decides to fry it and invite his friends for dinner.
One of the guests wanders into the kitchen and notices that the fish has a man's face and warns his companions not to eat the flesh. As soon as it is time to eat, they accept the gift, saying they will save it for later, but on the way they get rid of it.
One guest, however, leaves drunk and forgets to throw it away. On returning home, he recklessly gives the fish to his daughter, who eats it. By the time the man wakes up to warn her, it is too late. But as nothing happens to him, the matter is soon forgotten.
Years go by, the little girl grows up and gets married. But after that, she doesn't age a bit, and continues to look young, while her husband grows old and dies.
Exasperated by the curse of eternal youth and widowhood, she becomes a priestess and travels the world. Finally she returns to her hometown of Wakasa, where she ends her life at the age of 800.
The creature is first mentioned in the Nihon Sōki, one of the oldest Japanese chronicles, with the earliest ningjo records dating back to 619. Like most Yokai, their perception is ambivalent.
And some legends about ningjos are downright horror stories, even compared to mermaid tales from the Atlantic and the Mediterranean.
They are incapable of human speech, but instead make pleasant flute-like sounds. The ningjo is said to cry pearls instead of tears, while other sources say that if a Japanese mermaid sheds a tear, it becomes human.
Its particularly tasty meat is believed to give its consumers immortality and eternal youth.
However, its appearance is a bad omen, caught from the sea it is a sign of a storm, while a washed up ningj is considered a sign of war, so if one is caught in a fisherman's net it is thrown back.
However, interestingly, one of the main Buddhist deities in Japan is a ningjo, who goes by the name Ningjo Sinko. Perhaps this explains why some shrines keep and pray to mummified specimens of alleged mermaids.
The Edo period was the heyday of travelling circuses, or "miszemonos", in Japan. In these circuses, artists, performers, exotic animals and freaks were performed or displayed.
These were particularly popular with the people, as they were believed to bring good luck and health to the audience.
The creatures on display included mermaids, which were exhibited all over the world, mostly from Japanese and Indian waters. Japanese fishermen developed special techniques to make mummies as authentic as possible.
This involved adding mummified body parts of various animals, such as monkeys, owls, etc., to the dried fish body. The most famous of these is the Fiji Breast, which dates back to 1810 and is attributed to a Japanese fisherman.
It is thought to have been bought from him by the American businessman P.T. Barnum, who later exhibited it.
In addition, many other similar mummified ningjo and other Japanese spirit creatures (such as kappas and tengus) are still found in Buddhist and Shinto shrines throughout Japan.
The oldest and largest specimen (170 cm long), thought to be over 1400 years old, is kept at the Kannon Shrine in Siga Prefecture, Kannon Sodji, and is the subject of a special legend. According to this legend, the creature appeared to Prince Sōtoku as he passed by the shores of Lake Biva on one of his journeys.
The beast told him that it had once lived as a fisherman, and that its soul had been placed in the body of a fish as a divine punishment. He added that over the years he had come to realise the horrors of the extinction of life and that this had brought him enlightenment.
Before his soul was allowed to depart to the afterlife, he petitioned the prince to build a temple for the ningjo body and place it on the altar. This, he said, would help people to realise the sanctity and value of life.
The Prince did as the ningjo suggested: he built a temple and placed the remains of the mermaid inside.
Due to a series of strange phenomena, the body was moved to another temple, and then changed hands several more times before it was placed in its present location at the foot of Mount Fuji.
Like many other supernatural creatures, ningjōs often make a comeback in all areas of popular culture, be it manga, anime, video or role-playing games.