Hachiko was a real dog,he belonged to a Tokyo University professor named Eisaburo Ueno in the 1920’s.
Hachiko was the quintessential example of the spirit that embodies man’s best friend. He would see professor Ueno to the station every morning, and trot out to wait for him as he came home at night.
When the professor died, his wife moved out of Tokyo. She gave Hachiko to some relatives who lived near the station, but he wouldn’t stay with them. Every time he had a chance, he would dash away to Tokyo station to wait for his master.
Years later, one of professor Ueno’s former students heard about Hachiko’s constant vigil. He wrote about it, and the story quickly became a national sensation. People used the story as a symbol of the kind of loyalty they were trying to promote.
http://www.timeidol.com/hachiko-the-true-story-of-a-loyal-dog-2/