Internal exposure has become a major public concern as a result of the Fukushima Dai-ichi nuclear disaster. Hiroshima's “black rain” was the first event that revealed the significance of internal exposure. I began working on the black rain problem in 1985 after meeting Mr. Murakami Tsuneyuki, then Director General of Hiroshima “Black Rain” A-Bomb Sufferers Organization. But let me tell the story from the beginning.

I was born on September 11, 1923 ten days before the Great Kanto Earthquake that devastated Tokyo. I am now 88 years old. I studied at the Meteorological Technical Officials Training School (predecessor of the Meteorological College) for two years before joining the Navy. I was commissioned a second lieutenant in June 1945. On the day of the defeat, I was in Taisha Air Base near Izumo-Taisha Grand Shrine, Shimane, which sent attack aircraft to Okinawa. I worked there as a meteorological officer forecasting the weather. Although I did not know about the dropping of the Hiroshima A-bomb on August 6, I heard rumors that huge numbers of people, mainly soldiers, were brought to the Army Hospital near Izumo-Taisha, bandaged from head to foot. I knew something very serious had happened.