TOKYO — “Comfort women,” used by the Japanese military for sex, were present wherever the army invaded and occupied Asia countries from the early 1930s through the end of World War II.

That aspect of wartime history was kept quiet until the early 1990s, when a South Korean woman came forward, joined by some others, seeking Japanese help and accountability. Since then, the two countries have been divided over how badly Japan treated comfort women and how it should atone for past behavior.

That hasn’t changed despite a 2015 agreement intended to resolve differences. After South Korean activists installed a “comfort woman” statue in front of the Japanese consulate in the South Korean port city of Busan, Japan announced last week that it would temporarily recall its ambassador to South Korea and suspend economic talks.

The divide is reflected in the term “comfort women” itself. Both countries use it, but it means different things to each:

Who Are the “Comfort Women”?

The original Japanese word, “ianfu,” (pronounced EE-an-foo) is a euphemism for women sent to front-line brothels called “comfort stations.” Recruited or captured in Japan, the Korean Peninsula, China, the Philippines and Indonesia and elsewhere in Asia, they were used by hundreds of brothels supervised by the military, which set the tariffs, service hours and hygiene standards. The idea was to prevent venereal diseases and avoid triggering anti-Japanese sentiment by deterring Japan’s troops from raping local women.

Japan says there is no official record of the number of comfort women. Estimates by Japanese historians range from 20,000 to 200,000 depending on the parameters used. Initially, some were adult prostitutes or women from poor Japanese families, historians say. Later in the war, many non-Japanese, sometimes minors, were kidnapped or tricked into working in the brothels, some victims have said.

Japan and South Korea also used their own comfort women for American GIs after the war. Japan’s government set up brothels soon after its surrender in 1945 for U.S. servicemen pouring into the country and hired as many as 70,000 Japanese prostitutes, though Gen. Douglas MacArthur closed them in 1946. South Korea reportedly had a similar system for U.S.-led U.N. troops during the 1950-1953 Korean War and promoted sex businesses for American troops after the war. In 2014, about 120 former South Korean prostitutes and bar employees who worked near U.S. bases in the 1960-1980s sued their own government seeking compensation; a ruling is expected next week.

What Term Means in Japan

In Japan, comfort women initially were considered victims of World War II atrocities and thought to have come mainly from South Korea and the Philippines. Dozens from the two countries regularly visited Japan demanding official government apologies and compensation mainly in the 1990s-2000s. Years of continuous pressure for apologies have soured the initial sympathy, though, and many Japanese have grown weary of reminders of their country’s wartime past.

Some argue the women were not coerced but volunteered to be prostitutes for the military. During Shinzo Abe’s first term as prime minister in 2006-2007, his Cabinet adopted an official line that there was a lack of documentary proof the women were forcibly recruited or put to work in the wartime brothels. In 2016, Abe told a parliamentary session that replacing the term “ianfu” with “sex slaves” was inaccurate and said the widely used estimation of 200,000 women was groundless. Abe expressed his sympathy for the women, but described them as victims of human trafficking. He has repeatedly denied the women were coerced into sexual slavery. Japan has lobbied the United Nations to remove the word “sex slaves” from documents related to the issue. Japan’s largest newspaper, the Yomiuri, apologized in 2014 for using the expression “sex slaves” in its English edition in the past, promising not to use it again.

Japan issued an apology in 1993 and a government investigation concluded many women were taken against their will and “lived in misery under a coercive atmosphere.” A fund set up in 1995 paid nearly 5 billion yen ($44 million) for medical and welfare projects for more than 280 of the women, including 61 South Koreans. Many victims in that country rejected the fund money under their powerful support group’s stance to keep seeking further official apologies. Japan maintains all its wartime compensation issues with South Korea have been settled by a 1965 treaty.

What Term Means in South Korea

Most South Koreans prefer the term “comfort women” even though it is adopted from their former colonial ruler. Critics of the euphemism say it makes light of the women’s suffering, but the victims themselves generally have preferred it, perceiving more stigma from being called sex slaves. South Korea was a more deeply conservative society that prized women’s chastity and was hesitant to discuss sex publicly in the 1990s, when the women began revealing their long-hidden experiences.

The South Korean government uses the phrase “comfort women of the Japanese military” to reflect the victims’ preferences. The main support group for the women that organizes weekly protests outside the Japanese Embassy in Seoul uses “comfort women of the Japanese military” in its Korean-language documents. It uses the phrase “military sexual slavery by Japan” in English statements.

“I personally hope we don’t call them ‘comfort women.’ When Americans or other foreigners hear this term, I think they would say, ‘What’s that?'” said Jung Hye-kyung, an expert on Japanese colonial abuses.

Of the 239 South Korean women who officially registered themselves as comfort women, to obtain subsidies and benefits, only 40 are still alive. Experts believe many others have never come forward.

Story: Mari Yamaguchi, Hyung Jin Kim