This is the first book of Imae Yoshitomo (1932 -), and a forerunner of Japanese humorous children's literature after the war.
  A junior high school freshman, Yamane Jirô, called Pinky because his face is easily flushed, goes to his mother's hometown during summer vacation by himself. He admires Takasugi Shinsaku, and he regards his travel as training to be like Takasugi. He meets his childhood friend, Akiyo, there and knows that village children earn money by fishing and catching frogs in order to have a library at school. Jirô joins them in catching eels. Meanwhile, Ichirô and Saburô, Jirô's classmates, and Mr. Iyama, his classroom teacher, follow Jirô and come to the village. On the day of summer festival, village gangs try to steal cement for the school library. Jirô comes to know that and, although once he was caught, he has escaped and catches the gangs with his friends and his teacher. Through these experiences, Jirô matures.
  This story was first appeared serially in Gifu Nichinichi Shimbun [Gifu Daily News]. The author Imae said that Erich kästner influenced him in the way of describing groups of children. The description of laughter, which appears very often in this story, creates a cheerful atmosphere. The expectation of post-war democratic education can be seen in this story. The sea over the mountains symbolizes the future of children.
  Illustrations in black and white are by Chô Shinta, which go very well with the story and create a light-hearted humor.
  Yama no Mukô wa Aoi Umi Datta gathered little attention when it was published, but Tsurumi Shunsuke's comment for the Kadokawa Pocket Book edition in 1973 caused the re-evaluation of this story. One critic praised its humor and the element of first love in the story, while others criticized its over optimism or overly understanding adult characters. It was published in several editions from Rironsha and Kadokawa Shoten. It is said that in 40 years Rironsha has sold more than 130,000 copies.