TOKYO - Around 200,000 women were forced into sexual slavery for the Japanese military up to and during World War II.
Known euphemistically in Japan as "comfort women", the few who are still alive demand atonement from Tokyo for their suffering.
Japan offered an apology in 1993, the words of which remain government policy. But campaigners say many on the right, including Prime Minister Shinzo Abe, insult the memory of their suffering by playing down any official role by the country or its military.
Here are brief portraits of two elderly former sex slaves.
When Shinzo Abe addresses the US Congress on Wednesday, Lee Yong-Soo would like nothing better than to be seated up front, directly in the Japanese prime minister's line of sight.
"I wish I could sit smack in the front row... so that he can see right into my eyes," said the 87-year-old, one of the last and most outspoken survivors among the thousands of South Korean "comfort women" forced into Japanese military brothels during World War II.
Snatched from her home by Japanese soldiers in 1944 at age 16, Lee survived a harrowing boat journey to Taiwan, only to be held at a Japanese military brothel where she was repeatedly raped, beaten and subjected to electric shocks.
In testimony to the US Congress in 2007, Lee recounted how she was "attached" to a Japanese commando unit and forced to service four to five men a day.
"They were not in the slightest way sympathetic towards us," she said, recalling how the demands of the soldiers had to be met even after persistent bombing raids saw them evacuated to the nearby mountains.
"If the bombing ceased, the men would set up makeshift tents anywhere... and they would make us serve them," Lee said.
"Even if the tents were blown down by the wind, the men didn't pay any attention but finished what they were doing to us." Lee was sent home when World War II ended but, like most other victims, was afflicted by an overpowering sense of shame and kept silent for decades about her experience.
Then in 1991, a handful of former comfort women - encouraged by rights activists - began to speak out about their past, and Lee joined them a year later.
She soon became one of the group's most persistent voices, travelling across the world to speak at forums and symposiums - determined to ensure that what happened to her and thousands like her was recognised and not forgotten.
She was one of seven surviving comfort women who met Pope Francis when he visited South Korea in 2014.
Days before Abe's address to Congress, she travelled to Washington to make sure the testimony of the 50 or so surviving comfort women was also heard.
"Abe keeps lying... denying the fact that we were drafted against our will," she told reporters. "I'm not going to die until we resolve this issue."
Kim Bok-dong was only 14 when she was taken by Japan's military to work as a sex slave.
"On Saturdays from 12 to 5 pm and on Sundays from 8 am to 5 pm, there were long lines of men," the 88-year-old told reporters in Tokyo last week.
"How could I say that the life I led was the life of a person?" The military told her she would work at an army uniform factory, but instead she was taken from her village in South Korea to Guangdong province in China to work as a so-called "comfort woman".
Korea was a Japanese colony at the time, and Kim says she could not refuse to go for fear of being treated as a traitor.
After Guangdong, Kim was transferred to Hong Kong, Singapore, Sumatra, Malaysia and Java, where she had to have sex with soldiers for several months in each place.
She remembers there being about 15 men a day on weekdays and many more on weekends.
"If I didn't obey them, I would have been beaten. I had to do what I was told," she said. "I wanted to die." Kim said the Japanese government had a duty to speak the truth about comfort women.
"Now is the time (Japan) should recognise the mistakes that were made in the past. To deny it is such an absurd thing." She acknowledges that Abe himself was not guilty, but said as prime minister he "has responsibility to fix what was done in the past".
He should acknowledge the wrongs done in the past and apologise, Kim said.
"What I want is my dignity and honour back."