What was the Eugenics Protection Law?
The law, which was enacted in 1948, aimed to restrict a rapid population increase from the massive flow of repatriates from the battlefield, and a baby boom after World War Two.
It allowed surgical sterilizations to be carried out on people with mental disabilities or hereditary disorders without their consent.
At the time the law was enacted, it was believed that such disorders were hereditary. The law stated that its purpose is to "prevent the birth of inferior descendants."
Physicians would determine the necessity of sterilization and apply to the prefectural commission to examine its propriety.
The government also permitted physicians to restrain the body of patients, administer anesthetics, and deceive them about the purpose of the operation that was taking place, on the condition that such actions were limited to the minimum necessary level.
The Eugenics Protection Law remained in force for 48 years. About 16,500 men and women across Japan are said to have been sterilized without their consent under the law.
Meanwhile, the governments of Germany and Sweden, which also conducted forced sterilizations, have recognized them as a violation of human rights, and have issued a formal apology and compensation to the victims.
Since 1998, the United Nations has repeatedly called on the Japanese government to provide victims of forced sterilization with compensation.
But Japan's Ministry of Health and Welfare has refused to issue a formal apology and compensation, saying that it was legal at the time.
A 75-year-old plaintiff in Tokyo says he was 14 when he was sterilized without his knowledge. He was a resident at a welfare facility. He later married, but for most of his 4-decade marriage, he couldn't tell his wife about his past. He says he felt hurt when he saw his wife cradling a friend's baby.
The man finally told his wife 5 years ago, just before she died. "I felt very sorry for my wife. I hope the court will understand my feelings," he says.
Doctor looks back on forced sterilization
NHK spoke to a doctor in his 80s who says he conducted surgery once under the now-defunct law. He says the patient was a woman, aged about 20, who had a hearing impairment and a mental disorder.
The doctor says her parents told him they were worried that the girl might one day become pregnant. He says he applied for the surgery to the local screening panel, and was given the go-ahead.
The doctor says the parents were very happy. When asked about the numerous others who are thought to have been forcibly sterilized, the doctor says some may not have needed to undergo the procedure. He says that although it couldn't be helped at the time as it was government policy, it was all wrong in hindsight.
Moves to file lawsuits are likely to spread
The government has long maintained that the measure was legal at the time. It has never apologized. Nor has it offered any relief.
On the other hand, the governing coalition parties have recently launched a working group on the issue. A non-partisan group of lawmakers has also been formed. They're aiming to submit a bill to the Diet to offer relief to the victims.
Despite such moves, there are challenges. Many of the sterilization records have been lost. And some of the victims are severely disabled, making it difficult for their voices to be heard.