HIROSHIMA – “Hadashi no Gen” (“Barefoot Gen”), a manga series by the late Keiji Nakazawa, marks the 40th anniversary of its publication this year, reminding both child and adult readers alike of the horrors of nuclear warfare.

The series started in the June 4, 1973, edition of Shueisha Inc.’s Weekly Shonen Jump after Tadasu Nagano, editor-in-chief of the magazine, persuaded Nakazawa to depict his experiences as a survivor of the Hiroshima atomic bombing on Aug. 6, 1945. Nagano approached Nakazawa, who died last December, after being impressed by the cartoonist’s short story about the atomic attack.

“We were reminded that we had to learn more about the atomic bombing,” recalled Noritaka Yamaji, 65, who worked as an editor in charge of the series. Nagano died in 2001.

“Hadashi no Gen” describes the life of a 6-year-old boy named Gen before and after the city’s obliteration. Shueisha received a large number of letters from readers, including children, who said they had been able to understand the suffering of A-bomb victims for the first time or that they wanted to learn more about the event, even though they could barely look at some of the scenes depicted.

The gut-wrenching theme of the series failed to win widespread popularity, however, forcing Shueisha to discontinue it after one year and four months. Nevertheless, Nakazawa was able to “accurately get across his message to the public,” Yamaji said.

Takashi Yokota, 78, a reporter for the Asahi Shimbun at the time who was moved by the series, often visited Nakazawa’s home after Shueisha ceased publishing it and read letters from readers that were stuffed in a cardboard box. Recalling an early memory of his hometown in Toyama Prefecture, which was devastated by aerial attacks during the war, Yokota said he could not hold back tears.

When he learned that Choubunsha Publishing Co., a small firm in Tokyo, had accepted a proposal to publish “Hadashi no Gen” in book form after Shueisha rejected it, Yokota wrote a story with the headline: “Atomic bomb manga to become book, support quietly growing among youths.”

“People looked down on manga at that time, but I thought the great story of Gen should not be buried,” Yokota said.

“Hadashi no Gen” then began to be used for peace education and became available in libraries and classrooms. It has also been translated into some 20 languages, including English, and more than 10 million copies of the story in its various forms have been printed to date.

It was the first manga that found its way into school curriculums, Kazuma Yoshimura, a professor in the manga department at Kyoto Seika University, said. “People born in the 1970s and after have Gen at the center of their image of war,” he said.

Nakazawa continued to draw “Hadashi no Gen” for different publications, some unrelated to manga, including an opinion magazine for the Japanese Communist Party and a journal published by the Japan Teachers’ Union.

In 1987, he completed a 10-volume series of “Hadashi no Gen” and began to consider a sequel to the story.

He obsessed over how to convey the horror of the atomic bombing to readers, his wife, Misayo, 70, recalled, adding he often told her, “Gen will remain after my death and my goal will be attained if people read it.”