Images of a city smoldering and a river clogged with pale, radioactive cadavers never left Keiji Nakazawa’s mind.

The Japanese manga, or comic-book, artist used those images and other memories of surviving the atomic bombing of Hiroshima to create “Barefoot Gen,” a gruesome yet hope-driven comic about a boy who, like Nakazawa, survived the Aug. 6, 1945, attack.

Nakazawa was a first-grader standing outside his school when the United States dropped the bomb that killed more than 100,000 people, including his father, brother and a sister. He survived, as did his mother, but radiation sent her into premature labor. His newborn sister died days after the bombings at Hiroshima and Nagasaki that effectively ended World War II.

Nakazawa, who since the 1970s had used “Barefoot Gen” to make a case against nuclear proliferation, died Dec. 19 of lung cancer at a hospital in Hiroshima, according to Japanese news reports. He was 73.

“I wanted to put down on paper the scenes engraved in my mind,” Nakazawa told Tokyo’s Daily Yomiuri newspaper in 2009. “Everybody says the atomic bomb was terrible, but I wanted to use manga to show people just how terrible it actually was.”

His 10-volume magnum opus, which has been translated into several languages and adapted into films, cast blame for the bombing on both the United States and Japan and alluded to his longing for world peace.

Like Gen, his comic alter ego, Nakazawa advocated for peace.

Born about a mile from Hiroshima’s city center on March 14, 1939, Nakazawa and his mother spent the years after the bombing in poverty. He worked as a sign painter’s apprentice and dreamed of a life as a manga artist.

At 22, he packed up his sketches and moved to Tokyo, where he worked at various magazines. In 1973, at the urging of the editor of the Japanese magazine Boys’ Jump Monthly, he started writing “Barefoot Gen.”

What differentiated the manga most, Farago said, was its subject matter.

“Barefoot Gen” painted a painful and true account of suffering during a post-World War II Japan that longed for escapism.

Manga was his platform to challenge the norm and incite change.

“I’m a cartoonist, so cartoons are my only weapon,” he wrote in his autobiography. “Doubt is extremely strong, but we have to feel that change is possible.”