Keijiro Matsushimawas a 16-year-old student at a school in Hiroshima
when, on August 6, 1945, he remembers looking up and seeing two American bombers over the city.
''I just thought, ‘Beautiful planes shining in the morning sun’.
But the next moment there was a very strong flash
and a very strong shockwave and heat wave attacked me at the same moment.''
Matsushima describes the people he saw
as he made his way out of the city.
''Many of them had been so badly burned from head to feet.
Their charcoal-grey skin was peeling from their faces, arms and necks.''
An estimated 45,000 people died on the day of the Hiroshima explosion.
But during the following months, years and decades,
the death toll continued to rise
- up to an estimated 166,000 people.
''Even healthy people, seemingly with no injury, no burns,
they looked alright - but they became ill all of a sudden
with lots of strange symptoms
like high fever, or bleeding from the gums,
or many spots on their bodies.
And even doctors did not know how to deal with them.
People just named them ‘A-bomb diseases’, that's all.''
During the following decades,
these diseases would be recognized as forms of radiation sickness.
Now the crisis at the Fukushima nuclear power plant,
caused by damage from the tsunami,
is unleashing a new wave of radiation over parts of Japan.
The government has evacuated everyone from a 20-kilometer radius around the plant.
Some vegetables grown in Fukushima and neighboring prefectures
have been contaminated with radiation.
In Tokyo - 250 kilometers to the south -
parents have been warned not to give tap water to infants,
after it was found to contain high levels of a radioactive element.
The survivors of Hiroshima and Nagasaki
- the so-called ‘hibakusha’ -
have become the major source of information
on the effects of radiation exposure.
Professor Masaharu Hoshi of Hiroshima University has spent
three decades studying them.
He says his biggest fear now is a sudden surge in radiation levels
from the Fukushima plant.
''With Fukushima, one scenario is that people are exposed
to radiation gradually over a long time.
And that is not a problem.
But if later there is a nuclear explosion
and people get exposed over the course of couple of days,
that scenario really scares me.''
Hoshi says he fears information is being hidden from the public
about how serious the situation is.
''For example, the government says everyone
living beyond a radius of 30 kilometers from the plant
is OK staying at home.
But there are still dangerous areas outside that 30-kilometer zone.
The American government said the zone should be 80-kilometer.
For me that is the far better calculation.
Keijiro Matsushima says Japanese people
soon forgot the horrors of the atomic bomb after 1945.
''People thought so long as nuclear power is used
in peaceful ways, that's OK.
But we should have learned the evil of nuclear power
from the experiences of Hiroshima and Nagasakim.''
But, says Matsushima, the threat from Fukushima nuclear plant
has reminded Japan of what happened back then
- and the whole nation fears what may happen next.
''From now on we will have a very hard time.
I am afraid so.
But we have to do our best to recover and rise up again.
Yes we can!''
It is in that spirit that the firefighters and engineers
battling to prevent disaster at Fukushima have been embraced as heroes.
Japan knows only too well
the potential consequences if they fail.