A two-part English-language investigative documentary titled Inside Unit 731: Japan's Secret Human Experiments, produced by Singapore's Channel NewsAsia (CNA), has sparked widespread discussion online.

It reveals a hidden chapter in the history of World War II concerning the atrocities meted out by Japan's Unit 731 during its invasion of China. The documentary features interviews with the last surviving veteran of the unit, victims of the biological and chemical warfare and their families, and Singaporean scholars.

In pursuit of firsthand historical evidence, the film crew visited Quzhou, East China's Zhejiang province, in early November 2025 for on-site interviews and evidence collection.

The documentary, Inside Unit 731: Japan's Secret Human Experiments, is filmed in Quzhou, Zhejiang province. [Photo/WeChat account: quzhoufb]

The filming in Quzhou focused on the history of biological and chemical warfare. Zeng Xin, director of the interview team for this documentary, said this visit was a crucial part of the filming that aimed to use personal stories to draw the audience back into history.

Over three days, the team visited the exhibition hall displaying evidence of the crimes committed by Unit 731 in Quzhou. They also interviewed Wan Shaohua's team, who provided free medical consultations to elderly victims for a long time, and journalist Liao Zhengyan, who recorded victims' experiences. The documentary vividly reconstructs historical details through their stories.

The filming in Quzhou by the documentary crew ensures that the undeniable historical evidence reaches a global audience.