This is the fifth and the last instalment of a series.
Shoji Watanabe, 73, was sitting alone in a waiting room at a Kazuno hospital in Akita Prefecture for a regular checkup offered to atomic bomb survivors twice a year.
Seventy years ago, Watanabe, then 3 years old, was evacuated from Hiroshima to Akita but returned to Hiroshima with his mother six days after the atomic bomb was dropped on the city, where he was exposed to radiation.
A number of people were lying still on the streets, and the city was left to burn. Watanabe vaguely remembers those scenes, which he saw from his mother's back.
"Three bomb victims were in Kazuno," Watanabe said."But two died more than 10 years ago, and I'm the only one now. I have nobody to share experiences of the atomic bombing with. I'm lonely."
A movement against nuclear bombs spread across Japan in response to an incident in 1954 in which crew members of the tuna boat Daigo Fukuryu Maru were exposed to the fallout of a hydrogen bomb test conducted by the United States in Bikini Atoll.
An organisation of victims of nuclear bombs was formed in Akita Prefecture in 1961.
Kiyoji Terui, 88, was exposed in Hiroshima when he was stationed there as a soldier.
He joined the Akita chapter of the Japan Confederation of A- and H-Bomb Sufferers Organisations and tells his story at primary schools and women's clubs, calling for the abolition of nuclear weapons.
But in recent years, Terui, who is currently the Akita chapter's chairman, has rarely been asked to speak.
Terui had an operation for gastric cancer in early July and often receives hospital treatment. "The movement may end when the victims have all died," he said anxiously.
There were 183,519 A-bomb survivors in Japan as of the end of March, after the figure decreased by more than 80,000 over the past decade.
Of the nation's 47 prefectures, Akita Prefecture has the lowest number of victims - 27 - after 10 people died this year.
Younger generation's effort
Inevitably, the world will enter a time without A-bomb survivors in the near future, and the next generation is preparing before the time comes.
"We have always wondered why we can't abolish these terrible weapons ... There are many highly complicated issues related to national interests and international relationships. In the face of these obstacles, I sometimes feel that our actions [to abolish those weapons] might be useless."
So said Chisa Nishida, a junior of Nagasaki University's School of Medicine, in a speech she delivered in front of 150 international delegates attending the Preparatory Committee for the Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) held in New York in April and May last year.
She went on to say she is always inspired by the words of A-bomb survivors when she feels her efforts to abolish nuclear weapons are insignificant.
Nishida is from Hiroshima. Since her childhood, she has heard from many people around her that "A huge, huge bomb was dropped, and many people died." When Nishida became a middle school student, she had an opportunity to study the atomic bombing as a student journalist for a local newspaper.
There, she learned about people who gave up on marriage and childbirth because they were discriminated against because they had been exposed to radiation.
At the time of the Great East Japan Earthquake four years ago, Nishida saw a girl her age in the news on TV who was crying in the aftermath of the nuclear power plant accident. "I want to find out about radiation to help those who are suffering from discrimination and misinformation," she said.
That was why she chose to study at Nagasaki University's medical school, where she can learn the latest radiation medicine.
Despite being busy with her academic work, she joined the university's Research Center for Nuclear Weapons Abolition (RECNA) to conduct surveys of students regarding nuclear power.
It is believed that about 16,000 warheads exist in the world. At the 2015 NPT Review Conference held in April and May, nuclear states and nonnuclear states had intense confrontations over nuclear disarmament.
The conference failed to adopt a resolution, pushing the abolition of nuclear weapons further out of reach .
Even so, Nishida does not give up. This year, she was picked as the youngest-ever member of a committee to draft a peace declaration issued by Nagasaki.
She urged that the declaration include a message for young people. Nishida pursues her goal - with the words of nuclear victims in mind - to make the world free of nuclear weapons.
In the speech in New York, Nishida cited the words of a survivor that inspire her: "Humans created nuclear weapons, humans used nuclear weapons, and humans have the ability to abolish nuclear weapons."