The story follows the young narrator at a leisurely pace, from his first appearance as a primary school child a little before the second world war, to his young adulthood as an electrician. It starts as he and other small children search for a mochi tree, to use its bark for birdlime. Wandering off alone he stumbles on a little piece of ground, closed in by steep wooded slopes and a little stream. This becomes a favourite secret place to play. One day, he finds a young girl there. As she makes to leave, she finds that one shoe has gone missing. The narrator looks to see if it has maybe been carried off by the stream.
"There it is. Got it."For years after this, he searches for the little people, but never finds them. With the changes that the times bring, he ends up in a more distant town, starting work as an electrician. But he has not forgotten the little valley. He has no money, but he seeks out the owner of the land, to ask him to agree to sell it once he has saved enough. The owner agrees, and since he has no use for that bit of land, he allows him to start building a house on it.
Splashing through the stream I reached out my hand for the shoe. And then I instinctively pulled that hand back. Inside the little red gymshoe I had noticed something like the wriggling of an insect.
But it was not an insect. What I was looking at were two or three little people, no bigger than my little finger. They were looking my way and waving their tiny hands.
I stood there in shock and watched the shoe float by.
What? What was that?
Now the little people approach him from their side. They have been observing him for a long time and think he is someone they can work with. So they want him for an ally. It turns out that both narrator and korobokkuru need each other, as there is a plan to build a new road through the land, with compulsory purchase. The narrator and the korobokkuru must stop this, to save their home.
For readers looking for a fantasy of tiny people, the book might be disappointing. They are seen very much from through the human narrator's eyes. What we know of them is limited to his speculations and reports of what they tell him, so that we feel less close to their characters. Presumably we get to know some of them better in later books in the series. Where the book is strongest is in its sense of place and of nature, and of the attachments that a child can feel for a particular place. In this respect, it is a little reminiscent of books like Richard Jeffries' Wood Magic and Bevis.
There is an English translation, although I haven't seen it myself and it is probably hard to find: A little country no one knows, translated by Ruth McCreery. Kodansha International, 1988.