TOKYO, March 19 (Xinhua) -- Seiya Matsuno has spent many years studying modern Japanese history and the darkest chapters within it.

A researcher at the International Peace Research Institute of Meiji Gakuin University in Japan, Matsuno has long focused on Japan's history of aggression against China.

In a recent interview with Xinhua, he disclosed new details about the Japanese army's germ-warfare units in China. Stressing the importance of clarifying the truth of history, he said it is necessary to "lay a solid foundation" to prevent the "tragic history and war crimes" of Japanese militarist aggression against China from happening again.

In 2024, Matsuno discovered a roster at the National Archives of Japan containing information on technicians who served in the Japanese germ-warfare detachments during World War II.

He subsequently conducted an in-depth analysis of the material, and a paper based on his findings was recently published in Japan, shedding new light on the little-known operations of these notorious units.

Matsuno said previous research has established that technicians played a vital role in the germ-warfare units. They were the main personnel responsible for conducting human experimentation and developing biological weapons, and enjoyed treatment equivalent to that of senior officials.

His new study revealed some stark findings. Based on records of awards, performance evaluations, and promotions in the roster, Matsuno found that some technicians from the infamous Unit 731 who committed atrocities during Japan's invasion of China had been repeatedly rated "excellent" and given high evaluations.

Among them were Ando Koji, head of Unit 731's branch in Dalian, northeast China, and Yoshimura Hisato who repeatedly subjected living human beings to frostbite experiments, along with several others.

Matsuno said the fact that these individuals received high evaluations within the military lays bare the true nature of the bacteriological warfare units.

Deceptively dubbed the Epidemic Prevention and Water Purification Department of the Kwantung Army, Unit 731 was in reality a top-secret biological and chemical warfare research base established by Japanese aggressors in the northeastern Chinese city of Harbin during World War II.

Historical records show that 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.

For Matsuno, the significance of his research extends beyond history.

"The war of aggression against China by the Japanese militarism is an extremely tragic chapter of history," he said. "Clarifying the truth of history is of vital importance. We must seriously examine why such brutal acts occurred, and the historical context that made them possible."

Matsuno believes that such efforts are essential to establishing a solid foundation to prevent the tragic history and war crimes from recurring, and to ensure that science and technology are never again misused for warfare.

"With this understanding in mind," Matsuno told Xinhua, "I will continue working to uncover and study new historical materials."