South Korea urges Japan to make amends to second world war sex slaves ©Penta Press Kim Bok-dong, one of South Korea's surviving 'comfort women' Aged only 14, Kim Bok-dong had never ventured more than a few kilometres from the southern Korean town of Yangsan when she was offered work in a factory, to support the war effort of the occupying Japanese empire. Warned that a refusal could harm her family, she assented - never suspecting that she would spend the next four years being transported around far-flung regions of southeast Asia, being systematically raped by hundreds of Japanese soldiers. After her return home following the second world war, it took months for Ms Kim to admit to her family what had happened to her. When she finally did so, their response only reinforced her feelings of shame. "They said: "How could any human being do such a thing?"" she recalls. They were talking about the Japanese - and me, as well. Now 87, Ms Kim is one of a dwindling number of former sex slaves who stand at the heart of an increasingly damaging flare-up in diplomatic relations that is undermining military and economic co-operation between Japan and South Korea and having a knock-on impact on US ambitions in Asia. On Thursday - the 68th anniversary of Tokyo's defeat - South Korean President Park Geun-hye urged Japan's leaders to make amends to "those who, even now, carry with them the scars of history." From the early 1930s until its defeat in 1945, Japan operated "the largest and most elaborate system of trafficking in women in the history of mankind," according to Yuki Tanaka, a war history professor at the Hiroshima Peace Institute. He and other war crimes historians estimate that about 100,000 mostly Korean women were recruited - many through trickery or force - to provide sex to Japanese soldiers. Tokyo has given several expressions of regret for the abuses but Ms Kim - along with South Korea's government and most of its people - protest that it admitted only the "involvement" of military authorities, and that it has never offered state compensation to the women affected. The window of opportunity to address this grievance is closing: the death on Sunday of Lee Yong-nyeo, 87, reduced the number of surviving South Korean "comfort women" identified by rights groups to 57. "Soon there will be none left, and Japan seems to think that will resolve the problem," says one South Korean diplomat. But in fact that will just mean it can never be healed. Soon there will be none [of the women] left, and Japan seems to think that will resolve the problem South Korean diplomat Shinzo Abe, whose perceived attempts to play down Japanese aggression have sparked outrage in Beijing and Seoul, struck a conciliatory tone in a speech to mark Thursday's anniversary, promising to "humbly and squarely face history." While two members of his cabinet angered China and South Korea by visiting the Yasukuni shrine that honours Japan's war dead, Mr Abe stayed away. Even before the nationalist-leaning Mr Abe came to power last December, fraying relations between the countries - stemming largely from continued disagreements over this issue but also a territorial dispute over the Seoul-administered Dokdo Islands, known as Takeshima by Japan - had prompted the breakdown of a US-brokered military co-operation pact. This fed growing worries in Washington that the bad relations between its two major east Asian allies could jeopardise its efforts to boost its military and diplomatic presence in the region, a key foreign policy priority for Barack Obama's administration. The diplomatic stand-off has also cast a shadow over economic co-operation. "All in all, the state relationship between Korea and Japan is very bad nowadays," says Kim Jong-hoon, head of the foreign affairs committee of South Korea's ruling New Frontier party, and a former trade minister. For any agenda of economic co-operation, such as free trade negotiations, we need momentum to push things forward. But for the time being, there is a kind of anti-momentum pushing things backward. Since the Abe government took office, the situation has deteriorated further. In April, finance minister Taro Aso led a party of government officials to pay respects at the Yasukuni shrine. The next day, Mr Abe questioned whether Japan should rightfully be considered to have invaded other Asian countries during that period. Tokyo has extended its sincere apologies and remorse to all those women on various occasions Japanese foreign ministry The following month Toru Hashimoto, the high-profile mayor of Osaka, asserted that a "comfort women" system was necessary to maintain the morale and discipline of soldiers during war. He argued that there was no evidence that Japan had recruited any women against their will. His statement provoked outrage in Seoul and Beijing, and it is angrily rejected by Ms Kim. I was approached by an official who told me that I was required to make clothes for the army at a factory in Japan, and that my family could lose their home if I didn't go. So I went. But it wasn't Japan, it was war zones: Taiwan, Hong Kong, Guangdong, Malaysia, Sumatra, Java, Singapore, Bangkok. A spokesman for the Japanese foreign ministry said that Mr Abe was "deeply sympathetic and sensitive to the "comfort women" who experienced immeasurable pain and suffering." He said that Tokyo had "extended its sincere apologies and remorse to all those women on various occasions," and that it was keenly conscious of its responsibility in the second world war. He also noted the state's administrative and financial support - it contributed Y4.8bn - for the Asian Women's Fund created in 1995, which disbursed compensation to former "comfort women" but was funded largely through private donations. As long as her health permits, Ms Kim will continue to join the weekly demonstrations outside the Japanese embassy in Seoul, attacking Tokyo's position on the sexual abuses. Since 2011, the protest has had a permanent presence in the form of a bronze statue of a "comfort woman" - which drew criticism earlier this year from the Japanese ambassador, who warned that it would not improve bilateral relations. This argument failed to move Ms Kim. "The Japanese leaders are talking nonsense," she says. How can they tell these lies? I am the living proof of what happened.