I sat with a friend of mine from USC and asked her to tell me some folklore from her culture, maybe something mainstream. She is a Japanese girl approximately 20 years old and both of her parents were born and raised in Japan but she was born in California. She and I sat privately and got lunch on campus while she told me of Momotarō.
Momotarō was a child born out of a peach that was discovered by an elderly couple who raised him until he was able to leave his parents and fight off demons that were torturing his people. He wins the battle and returns a hero with his three friends, a talking dog, monkey, and pheasant. She tells me the story is retold in many different forms but as far as everyone knows this is the original which dates back to 1390. She believes it was told to encourage heroism and unity, and to push success out of the youth.
After briefly researching the subject I found that it is ~extremely~ popular in Japanese culture, for reasons I don’t totally understand because I am not from the area. The story has been converted into dozens of different variations including songs and war stories. There is even a festival held every year at a shrine for the young boy.