An elderly, illiterate hired woman in rural Showa-era Japan transmitted an entire cosmology of yokai (spirits and monsters) to young Mizuki through everyday talk, assigning specific spirits to specific places, weather, and fears. This folk tradition survived not in books or institutions but in one marginal person's casual storytelling.
Each named yokai attaches a recognizable form and story to an otherwise formless experience: a particular sound, shadow, illness, or dread is credited to a specific spirit. Naming the fear this way makes the inexplicable navigable, giving the child both an account of what happened and rules for how to behave around it.
Through NonNonBa's teaching the ordinary landscape becomes populated by an unseen second population of spirits occupying the same fields, houses, and darkness as people. Once this lens is adopted, the same physical place reads as crowded and watched rather than empty, changing how one moves through and attends to it.
The book presents the author's lifelong creative vision as rooted not in schooling or respectable authority but in time spent with a poor, uneducated old woman that the adult world dismissed. It argues that what a society discards as superstition or low status can be the very material that forms an artist's imagination.