The photo shows one of the horrific crimes carried out by Japan's Unit 731, infamous for carrying out bacterial experiments on living people.
Wearing protective suits, two Japanese soldiers are seen pouring chemicals on a five-to-six year old girl who is writhing in agony.
This is just one of the 450 documents revealed by China's State Archives Administration, on Japan's biological and chemical warfare during World War II.
The fact Unit 731 used poison gas against Chinese soldiers is also described in the documents.
China has long accused Japan of denying its wartime wrongdoings, and in what's being seen as a timely move, China is releasing evidence of Tokyo's wartime crimes, on the occasion of President Xi Jinping's visit to Seoul.
On top of the hard evidence, Beijing decided to release confessions of 45 Japanese war criminals, each one for 45 days,.. on its State Archives Administration website.
The handwritten confessions include one that says Japan kidnapped 20 women from Korea and China and used them as prostitutes for Japanese troops.
"These archives are hard evidence of the heinous crimes committed by Japanese imperialism against the Chinese."
An editorial from China's official news agency, People's Daily, added weight to the move, saying Beijing needs to open the eyes of right wing extremists in Japan who are denying history and breaking the nation's decades-long pacifist constitution.
Yoo Li-an, Arirang News.