In Korea they call them halmoni or grandmothers – although many are so scarred mentally and physically that they have never married or had children. In Japan, they are known as "comfort women", a hated euphemism for their forced role of providing "comfort" to marauding Japanese troops in military brothels. But around the world, another, altogether starker term will follow them to their graves: sex slaves.

Kang il-chul is one of a handful of the surviving women living their final days in the Sharing House, a museum and communal refuge two hours from the South Korean capital, Seoul. It is a stark, concrete building in a sparsely populated area of rice fields and scraggly mountain forests. But she says she has found some peace here. "I am among my friends, who treat me well," she says.

At the age of 15, she says she was taken and sent to a Japanese base in Manchuria. On her second night, before her first menstru-ation, she was raped. Soldiers lined up night after night to abuse her. She has scars below her neck from cigarette burns and says she suffers headaches from a beating she took at the hands of a Japanese officer. "I still have blood tears in my soul when I think about what happened," she says.

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Like many of the women, she finds it traumatic to recall the past, crying and knotting a handkerchief, and swaying as she talks. But she gets angry and slaps the table in front of her when the former Japanese prime minister Shinzo Abe is mentioned. "That horrible man," she spits. "He wants us to die."

Last year, Mr Abe stunned the Sharing House by claiming there is "no evidence" to prove the women were coerced, reversing Japan's position. Amid a political storm and pressure from Japan's US allies, he backtracked in a series of carefully worded statements that took the heat out of the controversy. But the denial "terrified" Kang. "I felt that my heart had been turned inside out," she says.

"The women's greatest fear is that when they die, the crimes against them will be forgotten," said Ahn Sin Kweon, director of the Sharing House.

Thousands of Asian women – some as young as 12 – were "enslaved ... and repeatedly raped, tortured and brutalised for months and years", according to Amnesty International. Sexual abuse, beatings and forced abortions left many unable to bear children.

Most survivors stayed silent until a small group of Korean victims spoke out in the early 1990s. Among the first was Kim Hak-soon, who was raped and treated, in her words, "like a public toilet". "We must record these things that were forced upon us," she said before she died.

The call was taken up by about 50 women, recalls Ahn Sin Kweon. "Many weren't married or were living alone in small towns, barely able to scrape a living." A Buddhist organisation helped construct Sharing House on donated land in the 1990s. "They were initially reluctant because the more they were out in the spotlight, the more people knew that they were raped. It is very difficult for women of that generation to discuss sexual matters openly, let alone these experiences."

Japan officially acknowledged wartime military slavery in a landmark 1993 statement, followed by the offer of compensation from a small private fund, which expired last year. But the so-called Kono statement has long baited Japanese revisionists, who deny the military was directly involved. "The women were legal prostitutes, earning money for their families," claims the revisionist academic Nobukatsu Fujioka.

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Although Mr Abe is gone, replaced by Yasuo Fukuda, Kang il-chul and her fellow victims fear it is only a matter of time before the denials return, perhaps with the next Japanese prime minister. The struggle defines the final years of their lives: if they lose, they will in effect be branded prostitutes.

When her health allows, the 82-year-old drags herself to a weekly demonstration outside the Japanese embassy in Seoul. The former sex slaves have been coming here since the early 1990s and marked their 800th consecutive demonstration in February. Their demands, including the punishment of those who raped them, an apology from the emperor and the building of a memorial in Japan, are angrily hurled against the walls, but are unlikely to be won.

The Wednesday protest, as it is known, has become ritualised and tinged with sadness as the already small group of survivors is reduced by illness and mortality. Of 15 former residents of Sharing House, just seven remain, most in poor health.

But the women are heartened by small victories. Last year, the US congress passed Resolution 121, calling on Tokyo to "formally apologise and accept historical responsibility" for the comfort women issue. Kang il-chul was one of the women who travelled to Washington to testify.

The resolution, sponsored by the Japanese-American politician Mike Honda, was fought hard by Tokyo. An editorial in Japan's largest newspaper, Yomiuri, said there was not "one shred of evidence to substantiate" the claim that the Japanese government systematically coerced and recruited the women.

Today, a large banner showing a beaming Honda is draped across the main courtyard of the commune. A copy of Resolution 121, signed by Honda and House Speaker Nancy Pelosi hangs in Ahn Sin Kweon's office. "The resolution was very important for us because our priority is to keep the memory of the women alive," he says, recalling Honda's reception when he visited here last November. "He was treated like a hero."

Surprisingly, perhaps, Mr Ahn reserves much anger for his own government. Like many activists, he believes Seoul bartered away any compensation claims when it signed a friendship treaty with Japan in 1965, in return for millions of dollars in soft loans and grants.

He says it is also up to the Japanese people to criticise their government. Every year, he says, about 5,000 Japanese travel to his office. Their encounter with the former sex slaves is often wrenching and tearful. Some stay as volunteers to work at the centre.

But Kang il-chul is deeply suspicious of Japanese journalists. "They want to show us weak and dying," she cries, again slapping the table in anger. "Especially the camera crews. They follow the oldest, sickest women around." Later, she stops me taking pictures of a frail woman blankly watching television. "You must show us strong," she demands and we take pictures of her posing, like a boxer, beside a monument to the sex slaves.

She recalls the day she was taken. "The soldiers had a list with my name on it. They put me in a truck. My nephew came out to look at them. He was just a baby. The soldiers kicked him and he died."

Memories like that make her strong, she says. "Future generations will call us prostitutes. Either they [the Japanese government] save their faces, or we save ours."