Kaneko began giving public testimony around 1996, at the age of 76. According to his testimony, he joined the army in 1940, and spread cholera into the water system of Linqing in September 1943.
In an interview with the Japan Times on September 26, 1996, Yasuji stated "I murdered 100 people or more by torture." He also stated that he murdered and raped many Chinese people.
He testified during an interview with English professor and activist Yun Chung-Ok in December 2000: "Comfort women were expensive. Therefore, I kidnapped, raped, and killed the Chinese women."
In an interview with the Washington Post he claimed that he raped many Chinese women during the invasion of China.
"They cried out, but it didn't matter to us whether the women lived or died," Kaneko said in an interview with The Associated Press at his Tokyo home. "We were the emperor's soldiers. Whether in military brothels or in the villages, we raped without reluctance."
In the Japanese documentary Japanese Devils, which features 14 Japanese soldiers retelling their roles in war crimes committed by Japan during World War II, Kaneko describes an incident in which he and his unit surrounded and wiped out an entire village for the thrill of it, rather than any threat it offered. The reviewer notes that all soldiers interviewed in Minori Matsui's film were ex-POWs of the Chinese government and subjected to a long "re-education" that may call their testimony into question. However, the Japan Times reviewer, Mark Schilling felt that "they give impression of being not communist controlled-robots but elderly men who have little time and nothing to lose" .
According to Japanese historian Ikuhiko Hata, Kaneko's testimony is not consistent with well-known historical facts. His division was located in Qingdao, so he could not have been a member of Unit 731, which was located in Manchuria, far Northern China. Hata concluded that if Kaneko did commit any atrocities, it was on his own initiative. Kaneko responded by saying that Hata had not experienced the horrors of war and did not know what it was like.
Otake, Tomoko. " Kill all, rob all, burn all" . Japan Times, September 26, 1996
^ Hiroko Tabuchi (March 1, 2007). "Japan's Abe: No Proof of WWII Sex Slaves". Washington Post. Retrieved 2007-08-30. Hiroko Tabuchi (March 4, 2007). "Soldier confirms wartime sex slavery". Japan Times. Retrieved 2008-01-17.
Mark Schilling (December 5, 2001). "Face to face with Imperial evil". Japan Times. Retrieved 2008-01-17.
Ikuhiko Hata 「終戦特集を検証する-「空想虚言症」の記憶にさいなまれる『朝日新聞』」 諸君 30(11) 1998.11