comfort women who served alongside the Japanese Army in the 1930s and 1940s and is credited with being the first to expose as fraudulent the testimony of Seiji Yoshida, who claimed to have kidnapped Korean women for the Japanese military. Hata, who argues that the comfort women were not sex slaves but largely willing prostitutes with a minority of them being sold by their parents and more crucially, no direct involvement by Japanese military except a few incidents in South East Asia, summed up his views on the issue with, There were at most 20,000 comfort women. None of them were forcibly recruited. Forty percent of them were from Japan, the most heavily represented nation. Many were sold to brokers by their parents. Some responded willingly to brokers' offers; others were deceived. I would add that, on the average, living conditions in the comfort stations were practically identical to those in brothels set up for American troops during the Vietnam War. Historian Chunghee Sarah Soh notes that Hata had put the total number of comfort women at 90,000 in 1993 but he later revised the number downward because of "his political alignment with the conservative anti-redress camp in Japan that emerged in the latter half of the 1990s". Hata would expand his research into the 1999 book Ianfu to senjō no sei ("Comfort women and sex on the battlefield"), described by Sarah Soh as "a 444-page treatise on the comfort women issue". Ianfu to senjō no sei was noted for its extensive compilation of information, being praised by historian Haruo Tohmatsu as "probably the most well documented study on the question" and by Mainichi Shimbun reporter Takao Yamada as "an encyclopedia-like collection of facts on comfort women". In The International History Review, A. Hamish Ion stated that with this work Hata has succeeded in creating "a measured evaluation in the face of sensational and supposedly ill-researched studies by George Hicks and others". The book was also favorably reviewed by political scientist Itaru Shimazu and the journalist Takaaki Ishii. By contrast, historian Hirofumi Hayashi criticized the work for faulty use of documents, such as where Hata cites a document listing 650 comfort women allocated in five prefectures, when in fact the document said 400 comfort women. Hata, who supports the retraction of the Kono Statement on comfort women, was the only historian appointed to the committee established by the government of