This photo taken on Dec. 12, 2024 shows exhibits on display at the former site of the headquarters of Unit 731 in Harbin, northeast China's Heilongjiang Province. [Photo/Xinhua]

The Exhibition Hall of Evidences of Crime Committed by Unit 731 of the Japanese Imperial Army on Thursday released a 38-minute video of a former member of Unit 731, a notorious Japanese germ-warfare unit during World War II (WWII).

In the footage, former Unit 731 member Tsuruo Nishijima detailed how the unit used meteorological data to carry out bacterial dispersal and frostbite experiments.

The video was recorded in 1997 by Japanese scholar Fuyuko Nishisato and donated to the exhibition hall in 2019, according to the hall, which was built on the former site of the headquarters of Unit 731 in Harbin, capital city of northeast China's Heilongjiang Province.

Jin Shicheng, a researcher with the exhibition hall, said that Nishijima joined Unit 731 in October 1938 and served in the unit's meteorological squad. The squad was not a simple observation section but rather an auxiliary force supporting the unit's human experiments in the field by measuring wind direction, wind speed and other conditions to ensure optimal experimental results, according to Jin.

Nishijima confirmed in the footage that "the meteorological squad had to be present at every field experiment." He testified to the "rainfall experiments" conducted by Unit 731, which involved aircraft releasing bacterial agents at extremely low altitudes.

At a field-testing site in Anda City, Heilongjiang, Unit 731 aircraft descended to about 50 meters above the ground and sprayed bacterial culture liquids onto "maruta" -- human test subjects -- who were tied to wooden stakes. Each experiment involved about 30 people, spaced roughly 5 meters apart. After the experiments, the victims were loaded into sealed trucks and transported back to the unit, where their symptoms and disease progression were recorded over a period of several days.

Nishijima also revealed that a Japanese military doctor once died after removing the mask and becoming infected during an experiment, indirectly proving the extreme virulence of the bacterial agents.

The video further disclosed details of the meteorological squad's involvement in frostbite experiments. To study wartime needs in frigid regions, the invading Japanese army forced the victims to expose their bodies for five to ten minutes in temperatures ranging from minus 20 to minus 35 degrees Celsius and observed their physical reactions.

According to the exhibition hall, Nishijima's video, a piece of oral history from a perpetrator's perspective, further reconstructs the criminal chain of Unit 731 and once again demonstrates that the invading Japanese army's biological warfare crime was systematic and inhumane, and was an undeniable historical truth.

Unit 731 was a top-secret biological and chemical warfare research base established in Harbin as the nerve center for Japanese biological warfare in China and Southeast Asia during WWII.

At least 3,000 people were used for human experiments by Unit 731, and more than 300,000 people in China were killed by Japan's biological weapons.