Kuma no Ko Ûfu was a creation of Kanzawa Toshiko (1924 -) who was highly praised with Chibikko Kamu no Boken [The Adventure of Little Kamu] in 1961, a story of a magnificent adventure which took place in a northern land where reindeers live. Kanzawa herself said later that although stories with full ups and downs are amusing, she wanted to create a story which approaches the essential quality of beings, without relying on the narrative itself. That was why she wrote Kuma no Ko Ûfu: she tried to do the same thing when writing poems (that is, to approach the essence of beings) in the field of books for younger children.
  Kuma no Ko Ûfu consists of nine short stories. The name of the protagonist, Ûfu, comes from his howling voice. He loves to imagine and to learn. In his and his friends' stories, things do not seem to have any inevitability at first sight, but they are connected and construct a logic in the end. In "Sakana niwa Naze Shita ga Nai" [Why Don't Fish Have Tongues?], Ûfu wishes to be a tree, then a bee, and a fish. He is teased by a carp and ran back home. After talking with his mother, he is happy to be a boy bear. In "Ûfu wa Oshikko de Dekite Iruka??" [Is Ûfu Made of Urine?], Ûfu is interested in what is made of what. He guesses a hen is made of eggs because she lays so many eggs. Tsuneta, a boy fox, knows Ûfu's idea, and says that "Ûfu is made of urine." Ûfu is very shocked by this, but later he realizes that he does many things - to think, to feel, or to be happy, which urine would never do. He comes to the conclusion that Ûfu is made of Ûfu. In "Chôcho Dake ni Naze Nakuno" [Why do You Cry Only for a Butterfly?], Ûfu is annoyed by Tsuneta's indication that crying over a dead butterfly and happily eating beef, a dead cow, is a contradiction. In "Kuma Ippiki Bun wa Nezumi Ippiki Bun ka" [Does the Amount for One Bear Equal to that for a Hundred Mice?] in a long dry weather, small animals complain that one bear can eat or drink that which can support 100 of them. However, Ûfu's father tells him that a bear eats and works in the amount of one bear, a mouse eats and works in the amount of one mouse. These stories show Ûfu's recognition of his identity. Pictures by Inoue Yôsuke broaden the image of Ûfu and his story.
  Kuma no Ko Ûfu is one of the few stories for younger readers which deals with essential questions and can be enjoyed by adults as well as children. Nakagawa Masafumi points out that these stories have realistic elements such as springboards to enlarge the field of imagination.
  Kuma no Ko Ûfu was published as one of the Poplar Pocket Book series in 1977, and Kôdansha Pocket Book series in 1978. In 2001, stories selected from Kuma no Ko Ûfu and its sequel Zoku Kuma no Ko Ûfu [A Sequel to Kuma no Ko Ûfu], were published in the form of three books: Kuma no Ko Ûfu, Konnichiwa Ûfu [Hello, Ûfu], Ûfu to Tsuneta to Mimi-chan to [Ûfu, Tsuneta, and Mimi-chan].