On 6 August 1945, Yamaguchi, a young engineer, was visiting Hiroshima. Seconds after getting off a tram at 8.15am he saw a massive flash of light and was knocked to the ground by the force of the bomb, and passed out as it detonated 600m above the city.
Around 140,000 of Hiroshimaâ€™s 350,000 people perished instantly. Though less than two miles from Ground Zero, Yamaguchi suffered only serious burns to his upper body and a perforated eardrum.
He spent the night in an air-raid shelter, with people dying and screaming in pain all around him. The following day, Yamaguchi navigated through the piles of burnt and dying bodies to catch a train 180 miles back home to Nagasaki â€“ which, like Hiroshima, was an important industrial and military base.
At 11.02am, and once again less than two miles from the centre, Yamaguchi saw a familiar flash of light. This time a 25-kiloton plutonium bomb exploded above Nagasaki, throwing Yamaguchi to the ground.
Tsutomu Yamaguchi was the only officially recognised survivor of both the Hiroshima and Nagasaki atomic bomb blasts at the end of the Second World War.