@This is a book that established Unno's fame and popularity as the author of military stories for boys. (Unno started his career as a writer of detective stories.) This story first appeared in Shônen Club [Boys' Club]. Soon it gained great popularity, and , just after the end of serialization, it was published in book form. Kabashima Katsuichi drew realistic illustrations which looked like photos.
@The story is as follows: a big floating island for airplanes is under construction in the Pacific Ocean. An English soldier, who is responsible for the construction, has a plot against Japan. He secretly makes the "floating island" not as a mere base but as an aircraft carrier, which can cruise by itself. He also tries to make a secret alliance with Russia against Japan. A young Japanese officer notices that, and, with the self-sacrificing help of his soldier, he succeeds in destroying the "floating island," and saves Japan.
@Unno said that learning science was more important than the strength of mind or economy. As enthusiastic devotion to the nation or the strength of mind was greatly valued in those days, Unno's recognition can be said somewhat objective at that era. Nevertheless, this story has strong nationalistic taste and stereotyped characters, which are the objects of today's criticism.
@A reprint of the original edition was published by Kôdan-Sha in 1960.