On August 6 1945, a Japanese school teacher was having her breakfast when, after a bright flash of light, she was buried in the darkness beneath a pile of rubble that once stood as her home.

She was still in her nightdress when she was dragged out of the pile of bricks by a neighbour and walked four miles barefooted across a burning bridge in search for her father, out in the country away from devastated Hiroshima.

Not much is known of Taza Shibama, although historians believe she was in her early 20s and worked as a teacher at a girls’ school in the Japanese city, teaching students aged 13 or 14.

Some survivors of the atomic blast went on to become advocates for the anti-nuclear movement, but an online search of Ms Shibama brings back very little results.

But her recollection of surviving the first use of a nuclear weapon in warfare was captured in an interview recorded by the Thames Television production company in 1972.

In it, she described the moment her house collapsed after a uranium bomb nicknamed Little Boy exploded over Hiroshima.

“It was so dark, I did not hear any sound at all. I did not know what happened,” she said

“The two-storey wooden building that was my house with eight rooms in it was blown down to pieces and covered me up.”

An audio clip of the interview is preserved at the Imperial War Museum (IWM) in London, which will be released online to mark the 75th anniversary of the dropping of the atomic bomb on Hiroshima.

“An account like hers, told in eloquent terms of what she was doing and how she survived, is quite rare,” said Anthony Richards, head of documents and sound at IWM.

“I think what’s so memorable about her interview is how she describes that moment when it happened in a very matter-of-fact way, it kind of brings it home how sudden and unexpected it was.

“She’s sitting in her kitchen having breakfast before she is due in school, with a bowl of rice in one hand and chopsticks in another, and the next thing she remembers is being in a pile of rubble.”

The United States detonated two nuclear weapons over the Japanese cities of Hiroshima and Nagasaki on August 6 and 9 1945.

The two bombings killed more than 100,000 people instantly, most of whom were civilians, and caused thousands more to die of their injuries or the after-effects of radiation.

Mr Richards said the teacher touches on how she suffered survivor’s guilt, a mental condition whereby a person feels guilt or shame for having survived a traumatic event while others died.

He added: “She was a teacher and a lot of those school girls didn’t survive, and those who did were put to work pulling down a lot of the wooden houses to stop the fire from spreading.

“In doing that, they were near the epicentre of the blast and got radiation poisoning.

“The teacher’s first thought was to flee the city to find her father in the country, while others were doing their bit to go through the rubble to find others.

“It’s very sad but you see that in different wars and conflicts, survivors trying to justify why they survived and not someone else.”

Japan surrendered on August 15 1945, bringing an end to the Second World War.

An extract of the audio recording, part of the IWM’s voices of war collection, will be released on the museum’s website and social media on Thursday.