Well, generally it is considered a true story. The story likely draws on real - world situations, perhaps from the author's own adventures or things he's heard about. It gives readers a sense of authenticity as if it could really have happened.
Indeed, 'Kensuke's Kingdom' is based on a real story. The author uses his personal experiences to create a vivid and believable world. He might have met someone like Kensuke in his travels, or perhaps experienced the feeling of being in a strange and unknown place himself. This real - life basis helps the readers to connect with the story on a deeper level, as they can imagine that such things could really occur.