Japanese film-maker Sunao Katabuchi was not born when atomic bombs were dropped on Hiroshima and Nagasaki in 1945.
But his father, who was in Saga prefecture in southern Japan, bore witness to the tragedy on that fateful day of Aug 9 in Nagasaki.
"He told me that he was able to see the mushroom-shaped cloud forming from the mountains in the direction of Nagasaki. And behind him, the glass windows of the houses were shaking," he tells The Straits Times in an e-mail interview.
"I could imagine the scenario of looking at the mushroom-shaped cloud from afar, but for the people under the cloud, I do not dare let my imagination run wild."
There is an echo of this scene in the anime In This Corner Of The World, which is showing in cinemas. It was directed and co-written by Katabuchi, adapted for the big screen from the manga of the same name (2007-2009) by Fumiyo Kono.
It is about the life of an ordinary young woman, Suzu, in wartime Japan. In the movie, she sees a mushroom cloud in Kure city, which is 20km away from Hiroshima.
Katabuchi, 56, says: "I could feel that it was my destiny to make it into an animation."
For the project, he did a lot of research into "how the people led their lives and what they were thinking during the period".
The production team lovingly recreated the look of pre-bomb Hiroshima and even studied fashion trends.
"Previous war dramas portrayed the women wearing work pants, but, in fact, they did not wear them until the mid-war period, the reason being that such attire was seen as inappropriate," he says.
His quest for authenticity extended to the use of a Hiroshima dialect that is no longer spoken regularly and even Japanese people "might also not understand all the dialogue".
Acknowledging that the historical accuracy might be distancing, he says: "However, we can feel that Suzu is someone whom we might know in our surroundings and she is the one who will lead us to this unfamiliar world."
It also helps that she is voiced with provincial homeliness by actress-model Non.
The film has been a hit in Japan, grossing more than 2.5 billion yen (S$30 million) and earning various accolades, including the Japan Academy Prize for Animation of the Year and the Hiroshima Peace Film Award from the Hiroshima International Film Festival.
It is a success that Katabuchi shares with his wife Chie Uratani, who co-wrote the script.
The couple have often worked together on animated films, including a feminist fairy tale Princess Arete (2001) and youth drama Mai Mai Miracle (2009).
He says: "We are not working together as a family, but it's more because we share the same goals. We are good partners at work. Therefore, she does not want to be known as 'Katabuchi's wife', but more as the position of creator and animator."
•In This Corner Of The World is showing in cinemas.