Chinanews, Nanjing, May 10 - Lei Guiying, the last "comfort woman" (wartime sex slaves) in Nanjing passed away several days ago, which was sad news to historians, for most witnesses of that part of history in China are gone.Zhou Fenying, a former "comfort woman" of over 90 years old from Rugao of Jiangsu Province, was brave enough to come into the open recently. Chinese historians call for a widespread concern for the preserving of the documents and information of the history of the "comfort women".According to current researches, most former "comfort women" alive today live in Heilongjiang, Shanxi and Hainan provinces, and some can be found in Shanghai, as well as Jiangsu, Hunan, Hubei, Hebei, Henan and Shandong provinces. Nowadays, 45 of them have come into the open to give witness accounts of that part of history. None of them are leading a well-off life, and nearly all of them are quite old."There is no particular policy to guarantee their life," said Su, a historian. The Comfort Women Research Center has launched a donation project to support former “comfort women”, whereby each of them was able to receive an allowance of 100 yuan every month. Later, the allowance had increased to 200 yuan, but still not enough.Quite a large number of wartime brothels were located in Nanjing during the anti-Japanese war, including the biggest one. However, not too many witnesses were found there. "We have found condoms and matting at the sites of those brothels, but those are not conclusive evidences," said Jing Shenghong, a history professor of Nanjing University.Actually, not many former “comfort women” and their family members would like to reveal the disgraceful past of the women, thus most of them would rather hide their identities.