Jilin Archives in northeast China on Friday released 60 original Japanese military documents from World War II, adding new evidence of Japan's wartime system of forced sexual slavery.

The release coincided with the 95th anniversary of the "September 18 Incident." It was on September 18, 1931, when Japanese troops blew up a section of the railway near Shenyang, then under their control, and accused Chinese troops of sabotage as a pretext for subsequent aggression.

The new archives came from charred historical remnants left behind after the Japanese Kwantung Army attempted to destroy them during their retreat, according to the Jilin Provincial Archives in Changchun, capital of Jilin Province.

The original Japanese military documents shed further light on the systematic and institutionalized sexual violence committed by the Japanese army, powerfully debunking the long-standing lies of Japan's right-wing forces that distort the facts surrounding the "comfort women" issue and attempt to whitewash Japan's war crimes.

Previous research has shown that some 400,000 women in Asia were forced to serve as "comfort women" – sexual slaves for the Japanese army during World War II – and nearly half of them were Chinese.

Lyu Chunyue, an official with the archives, said the archives now has 85 original Japanese military documents documenting the "comfort women" system. The first 25 were released in 2014 and were later included in China's documentary heritage.

The 60 newly released documents cover the establishment and authorization of "comfort stations," their daily operation, the recruitment of sex slaves and their brutal treatment, Lyu said.

The documents show that "comfort stations" were established and operated under the authority of the Japanese military, with the Japanese Kwantung Army setting up more than 20 such facilities in Northeast China.

Some archives show that military approval was required to establish new "comfort stations," and some were located inside Japanese military barracks and were restricted to military personnel.

The new archives also include records on the forced recruitment of sex slaves. A 1941 report by a Japanese military unit said that Japanese troops forcibly recruited Korean women when women could not be recruited voluntarily.

Other archives showed that "comfort women" were forcibly conscripted to the front lines under Japan's national mobilization law, thoroughly refuting the fallacy that their recruitment was voluntary.

The documents also recorded violence against the sex slaves at multiple "comfort stations."

"The release of these original archives, irrefutable proof of crimes against humanity committed by Japanese militarism, provides solid historical evidence for defending historical truth and countering historical revisionism," said Su Zhiliang, leading expert for China's bid to list "comfort women" materials on UNESCO Memory of the World Register.