HARBIN -- The former site of the headquarters of Unit 731, a notorious Japanese germ-warfare unit during World War II (WWII), reopened to the public on Friday, featuring a special exhibition showcasing evidence of its germ-warfare activities.

Nearly 2,100 items, including archives, historical materials, relics and publications collected by the Exhibition Hall of Evidences of Crime Committed by Unit 731 of the Japanese Imperial Army in recent years, were unveiled at the exhibition, according to Zhang Yang, deputy director of the facility.

Zhang said that some of the newly displayed evidence serves as crucial supplements to existing historical materials and provides valuable resources for further research on Japanese germ warfare activities during WWII.

According to Zhang, this exhibition has also put on display various medical journals published in Japan between the 1920s and the 1940s, totaling 347 volumes. Joint research by the exhibition hall and Heilongjiang International University has identified 42 medical papers authored by core members of Unit 731, including Shiro Ishii and Masaji Kitano.

Jin Shicheng, a researcher with the exhibition hall, said that these wartime medical journals document numerous so-called "research achievements" published by Unit 731 members, involving bacterial and viral diseases such as anthrax and plague.

"This evidence highlights interactions and personnel exchanges between Japanese wartime medical universities, army hospitals and research institutions with Unit 731, exposing the role of Japan's medical community in supporting the war of aggression against China," Jin said.

The exhibition also showcases litigation documents on incidents involving chemical weapons abandoned by the Japanese army in China, along with confessions from Japanese war criminals.

In addition, 616 relics collected by the facility in recent years and donated by private owners, including military sabers, uniforms, medical equipment, bacterial bombs and Japanese military medals, are on display.

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.

Since last winter, the exhibition hall has attracted over 3.5 million visitors.