The government didn't want the general public to know what our weapons had done
On Aug. 6, 1945, the United States dropped an atomic bomb over Hiroshima, killing at least 70,000 instantly and perhaps 50,000 more in the days and months to follow. Three days later, it exploded another atomic bomb over Nagasaki, slightly off target, killing 40,000 immediately and dooming tens of thousands of others. Within days, Japan had surrendered, and the U.S. readied plans for occupying the defeated country -- and documenting the first atomic catastrophe.
But the Japanese also wanted to study it. In early September, just after the Japanese surrender, director Sueo Ito set off for Nagasaki. There his crew filmed the utter destruction near ground zero and scenes in hospitals of the badly burned and those suffering from the lingering effects of radiation.
Then, on Oct. 24, 1945, a Japanese cameraman in Nagasaki was ordered to stop shooting by an American military policeman. His film, and then the rest of the footage, was confiscated by the US. An order soon arrived banning all further filming. This footage, along with footage taken by the US military, was locked away for over 40 years. Even today, much of it has never been viewed by the public.