Nagai Nagai Pengin no Hanashi is a story of penguin brothers growing up in a harsh environment. Although penguins are personified, the story is generally based on penguin ecology. It is a pioneering work of postwar literature for younger children.
  The story begins when the penguin brothers were hatched. The adventurous elder was named Ruru, the discreet younger Kiki. When Ruru goes out to the snowfields, he has a narrow escape from a seagull, and is found by a human who is engaged in whale fishing. Fellow penguins surround the whaling ship and recover Ruru. In summer, Ruru and Kiki, asleep on a small iceberg, wake up to find they are adrift. After being rescued by Gai, a young whale, they are attacked by a grampus. Ruru plunges into the sea to distract the grampus’s attention and succeeds in saving Kiki and Gai. Ruru reaches an island ruled by the king of emperor penguins and is captured. Disgusted with the tyrannical king, a guard runs away with Ruru. Later when the brothers grow larger, they neglected swimming practice, and were just watching it when a group of seagulls attack. Ruru, all alone, is protected by his swimming teacher who is wounded. Ruru regrets his selfish behavior.
  Nagai Nagai Pengin no Hanashi was of great significance at a time when it was considered that stories for younger children should be short. Before publication, Inui Tomiko (1924-2002) had the story read at a nursery school so as to confirm that it was acceptable for younger children. It also introduced a new genre of animal fantasy. Nagai Nagai Pengin no Hanashi first appeared in a coterie magazine and then serialized in a magazine called Kodomo no Shiawase [Children’s Happiness] from October 1956 to January 1957. It was published in book form after some revision. It went out of print due to bankruptcy of the publisher, and then Rironsha published it in 1963 in a large-sized edition. It was included in Iwanami Shônen Bunko [Iwanami Children’s Library] and when it was revised in 1990, the story was rewritten to accomodate new knowledge on the ecology of penguin, which shows how the author insisted on describing animal life as true as possible.
  Illustrations of the first version disappointed Inui since they emphasized on the cuteness of penguins. In the Rironsha edition, they were changed to a more realistic style by Yamada Saburô.
  When the first edition of Nagai Nagai Pengin no Hanashi was published, its strong appeal to readers was highly praised. Nagai Nagai Pengin no Hanashi was introduced in China and Slovakia, and was made into a film using dolls as well as into a kamishibai (a picture-story show).