Christopher Nolan reveals one of Oppenheimer’s most shocking lines was improvised

In one scene, US Secretary of War Henry Stimson makes a trivial decision about the targets for the atomic bombs

Christopher Nolan has revealed that one of the most horrific lines of dialogue in Oppenheimer was improvised by an actor.

The film stars Cillian Murphy as theoretical physicist J Robert Oppenheimer – the man who developed the first nuclear bomb for the top-secret Manhattan Project.

One scene depicts Murphy’s Oppenheimer meeting with US Secretary of War Henry Stimson (played by James Remar) and other government officials for a discussion about where to drop the atomic bombs in Japan.

In one shocking line, Stimson rules out Kyoto because he and his wife honeymooned there. The off-hand, subjective way in which the fates of thousands are decided causes the other men in the room to visibly squirm in their seats.

In an interview with The New York Times, Nolan revealed that Remar had come up with the line himself.

“[Remar] kept talking to me about how he learned that Stimson and his wife had honeymooned in Kyoto. And that was one of the reasons that Stimson took Kyoto off the list to be bombed,” the director said.

“I had him crossing the city off the list because of its cultural significance, but I’m like, just add that. It’s a fantastically exciting moment where no one in the room knows how to react.”

Christopher Nolan directs Cillian Murphy in ‘Oppenheimer’ (AP)

“Each actor was coming to the table with research about what their real-life counterpart had been,” Nolan said earlier in the interview.

“They had tons of homework to do. They had a great resource with American Prometheus [the Oppenheimer biography on which the film is based]. They then did their own research and what it meant for me, which isn’t something I’d ever really been able to do in the past.

“So, for example, with the scene in the section classroom with all the scientists, we would be able to improvise the discussion. The script is there, but they could come into it with passion and knowledge based on all of their own learning.”

The USA detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki, respectively, killing approximately 200,000 people, most of whom were civilians. It remains the only use of nuclear weapons in an armed conflict.

The Independent understands that plans have not yet been finalised for Oppenheimer’s theatrical release in Japan.

The film’s coinciding release with Greta Gerwig’s Barbie movie has caused discomfort in Japan as people combine the films to make “Barbenheimer” memes, which have been criticised for trivialising the atomic bombings.

Warner Bros was forced to apologise to its own Japan branch after engaging with one such meme that depicted Barbie star Margot Robbie with a hairstyle in the shape of a mushroom cloud.

“Warner Brothers regrets its recent insensitive social media engagement. The studio offers a sincere apology,” Warner Bros US said after its Japanese arm called their interaction “regrettable”.

Oppenheimer is out now in cinemas.