The story of Momotaro is a beloved bit of folk lore in Japan. It is a story that combines a bit of Moses and a coming of age story. Momotaro is a child of the heavens transported in a peach, which a poor elderly couple were about to eat until the child talked informing them about his origins. When Momotaro turned fifteen he wanted to do something to help his country and set off to Onigashima or Ogre Island to fight the Ogres that have been terrorizing his home. Along the way he befriends a dog, monkey and a pheasant by giving them food. In exchange the trio agrees to help Momotaro. Naturally, the quartet defeated the Ogre menace and returned home with wealth and everyone lived happily ever after.
Knowing this it is easy to see why this story was so popular during World War Two. Brave son on a righteous quest to defeat the enemies of their home country. Then again America at the time wasn't so much different. We did and still do have a paramilitary organization in the Boy Scouts. We saw how american cartoons were made to dehumanize our war time opponents. Plus, after December seventh we had our own campaign to demonize and compartmentalize Japanese-Americans in interment camps. I guess the adage of: "All's fair in love and war" is true.