A new piece of evidence related to the Nanjing Massacre has been donated to a private museum in Nanjing, Jiangsu province. Japanese war criminal Hisao Tani wrote in Chinese calligraphy on a scroll, boasting of Japanese soldiers' “valiance” in Nanjing in 1937, when over 300,000 people were killed within six weeks.

On Dec. 8, the Nanjing Civil Museum on the War of Resistance against Japanese Aggression unveiled the latest donation from noted historian Yu Ge. The scroll is the height of an average adult, and has become wrinkled over the years. “Valiant invasion of Nanjing,” is written in Chinese characters on the scroll, along with Tani’s signature.

Hisao Tani was a commander of the Japanese Army's Sixth Division during the war. He and his troops committed mass murders, rape, looting and destruction in Nanjing. Tani was executed on April 26, 1947.

“This is direct evidence of the atrocities committed during the Nanjing massacre,” Yu told Nanjing-based news site Longhoo.net. At a press conference, Yu said he gave the scroll to the museum for free so that the public can better understand history.

“Nanjing is where [the scroll] belongs, where the atrocities happened,” he said.

According to Yu, the scroll was likely made during the propaganda campaign in Japan in 1938, for which Tani was called back to his home country. It may have been given to his superior, Terauchi Hisaichi, to boast of his “achievements.” The scroll likely then became separated from Hisaichi after Japan lost the war.

Yu said he bought the scroll in 2007 from a Japanese website. He said he identified the scroll as authentic based on a mark that Tani left at the end of his message, Longhoo.net reported. An identical mark was also left by Tani on an army flag during the war, along with his signature. The flag has been preserved by the Memorial Hall of the Victims of the Nanjing Massacre by Japanese Invaders.

The army flag and scroll are reportedly the only two remaining relics featuring Tani's handwriting. Both will be displayed at the museum and memorial hall.