Short answers, pulled from the story.
Japanese folklore encompasses the informally learned folk traditions of Japan as expressed in oral traditions, customs, and material culture. The academic study of this field is known as folkloric studies, and practitioners use the term "folklore material" to describe the objects and arts they examine.
The Namahage are men who dress in ogre-like masks and traditional straw capes called mino and make rounds of homes in an annual ritual on the Oga Peninsula in the Northeast region of Japan. They masquerade as kami and are meant to instill fear in children who have been idling lazily by the fire.
The Shikoku Pilgrimage is a circuit of eighty-eight temple sites, commonly known as ohenro-san. Pilgrimage to major sacred sites declined after the Edo period, but this particular route has more recently become fashionable, supported by popular media and cottage industries.
Mukashi-banashi is the term for common Japanese folktales, meaning stories of "long ago" or from "bygone times." These tales typically open with the word "Mukashi," equivalent to "Once upon a time," and close with a set phrase such as "dotto harai."
Sazanami Iwaya was a children's story author who lived from 1870 to 1933 and is often called the Perrault of Japan. His retellings of classic tales like Momotarō had a strong hand in establishing the forms of those stories most widely recognized today.
The Mingei movement, spearheaded by Yanagi Sōetsu, sought to appreciate folk craft from an aesthetic viewpoint. It argued that everyday handmade objects deserved recognition as art, not merely as ethnographic specimens.