I came across this paper by a Japanese historian. He claims that there is no objective evidence that the Japanese army ever enslaved Korean women for prostitution, other than the testimony of sixteen victims prepared by the Korean government. He's unabashedly right wing and patriotic, but is what he says here true?

This masochistic drift of public opinion within Japan reached its peak in August 1993 when Chief Cabinet Secretary Kouno Youhei officially acknowledged and apologised for the enforced prostitution of Korean women by the Japanese army: "With regard to recruitment of comfort women, businesses who took orders from the Army were the key players but, even so, there are many examples of people being assembled against their wishes by means of enticements or force. It is clear, too, that the Military Police were also directly involved."

At this time, the Japanese government devoted all of its energies to searching for materials that proved this prostitution was enforced, but none were found. Even so, Japan was issued with strong demands from the Korean government to 'restore the honour of these women by acknowledging that prostitution was enforced on them,' and it subsequently issued an apology based on statements from sixteen witnesses prepared by the Korean government, without even cross-examining them. It is worth nothing that the content of these statements has not been made public to this day. Underlying this apology was the preconceived notion that the Imperial Japanese Army had undoubtedly carried out evil actions, and that these Korean women were hardly likely to have lied....

As a result of chief cabinet secretary Kouno's informal remarks, all junior high school history textbooks have since 1997 provided an account of the 'comfort women issue'. However, in that same year, research by the journalist Sakurai Yoshiko showed that Kouno's statement was the outcome of diplomatic considerations, and that no objective proof existed. Consequently, the realisation spread that Kouno's remarks could not possibly form the basis of any historical account. But outside Japan, Kouno's remarks were seen as absolute, evidence-based proof of the Japanese government's acknowledgement of guilt. The situation now is one where people take the extreme view and insist, in all seriousness, that to doubt or deny the enforcement of prostitution by the military is on a par with denying the Nazi holocaust....

...research by Koreans themselves and by the Japanese historian, Hata Ikuhiko, has made it clear that the confessions of Yoshida Seiji about his rounding up of comfort women on the island of Jeju do, off the coast of Korea, which is regarded as the classic case of sexual slavery, are a fabrication. ^(Hata, Ianfu o Senjo no sei, pp 229-48. See the Korean writer, O. Sonfa, who also denies the possibility that the Japanese could have enforced sexual slavery (Seikatsusha no Nihon tochi jidai, pp42-4, 54-5, 223-4))

This is from: Nitta, Hitoshi. “And Why Shouldn’t the Japanese Prime Minister Worship at Yasukuni? A Personal View”. Yasukuni, the war dead and the struggle for Japan's past. Edited by John Breen. New York: Columbia U Press, 2008. Print.