The nine tailed fox or fox spirit having been originated from Chinese mythology and writings lead back to the Han dynasty (4th to 1st century BC). Therefore, it's just a collection of declares rather than a scientific work! To write this article I researched on folklore and books, but also in insecure sources like private blogs and Wikipedia. Even today they are a popular figure of Animes, video games, dramas like Legend of Nine Tails Fox and movies like Hometown Legends (Episode 8).
It is one of the most powerful mystical creatures in some Asian countries as China, Japan, Vietnam and Korea. Mystical creates like vampires and werewolfs are very popular in the western world as the nine tailed fox is known in Asia.