Newly deciphered Japanese wartime archives offer fresh evidence of atrocities committed by Japanese troops during the invasion of China.
The Jilin Provincial Archives has released 89 files related to Japan's Kwantung Kempeitai (military police corps) and the then "central bank" of the Japanese-aligned puppet state of Manchukuo.
Experts said the archives are of great historical value, as they refute the denial of war crimes by Japanese right-wingers.
"The Abe administration and Japan's rightists have tried to disown history by glorifying or giving ambivalent definitions of Japan's invasion," said Jiang Lifeng, a research fellow at the Institute of Japanese Studies under the Chinese Academy of Social Sciences. "Now they can find answers to 'what an invasion is' through the documents."
"I was stunned when I visited the Jilin archives two months ago and saw such a colossal volume of files kept in such good order. These files fully expose the atrocities of Japan's militarism," Jiang said.
For example, a report on an investigation into "restoration of public order by Nanjing Kempeitai" by Commander Ooki Sigeru on February 28, 1938, said that the population of Nanjing was about 1 million before December 1937, when the Nanjing Massacre took place.
At least 300,000 Chinese civilians and unarmed soldiers were killed by invading Japanese troops in the massacre.
But some Japanese rightists have tried to deny the massacre by claiming the population in Nanjing before the Japanese occupation was no more than 300,000, Jiang said.