On Oct 1, China's National Day, the Exhibition Hall of Evidences of Crime Committed by Unit 731 of the Japanese Imperial Army in Harbin, Heilongjiang province, received 10 new historical artifacts.

Among them were the badge of a junior officer from Unit 673 — a branch of Unit 731 — and detailed expenditure records of Japan's biological warfare units.

Some of the pieces are believed to be the only publicly available evidence of Unit 731's crimes in China.

What surprised many was the identity of the donors — four young people in their teens and early 20s.

The organizer of the effort, 16-year-old Xu Weizhe, said the group raised over 100,000 yuan ($14,033) entirely on their own to purchase the relics.

Unit 731, a top-secret biological and chemical warfare research base established by the Japanese Imperial Army in Northeast China, became known as a "death factory" during the Chinese People's War of Resistance Against Japanese Aggression (1931-45).

The unit conducted a series of inhumane experiments on civilians and prisoners of war, including bacterial infection tests, vivisections without anesthesia, and frostbite studies. It also unleashed biological weapons in several parts of China.

According to China Services Info, Unit 731 was responsible for the deaths of at least 3,000 human test subjects and over 300,000 victims across the country.

Today, Chinese researchers continue to gather evidence of Japan's wartime aggression, with public donations playing a crucial role in preserving the historical record.

Xu said most donated items related to Unit 731 have traditionally come from the collections of older generations.

"The staff at the exhibition hall told us we were the youngest people ever to spend our own money on acquiring such relics. They were very moved," Xu said.

From pain to purpose

Xu, a native of Nanjing, Jiangsu province, comes from a city marked by history. In 1937, Japanese invaders carried out a brutal massacre there — now known as the Nanjing Massacre — which claimed at least 300,000 lives in just six weeks, according to the 1947 verdict of the Nanjing War Crimes Tribunal.

Xu's elders were survivors of that atrocity. "My family has told me about that history since I was a child," he said. "It's something carved deep into my bones — I can never forget it."

This personal connection to history aligns with the shared passion of Xu and his friends for collecting antiques, a hobby that has honed their ability to identify historical relics and tap into private collections. Earlier this year, they decided to use their skills for a greater purpose and launched the project in August.

"We hesitated at first," Xu admitted. "Collecting evidence of wartime crimes requires a lot of money and professional knowledge to verify authenticity. But we decided to just start and see how it goes."

To raise money, they sold part of their personal antique collections, securing 100,000 yuan as seed funding. They then launched a multichannel search, posting online appeals and visiting private museums and collectors.

"Initially, we planned to spend a whole year on the project and make the donation on Sept 18 next year," Xu said, referring to the national day of remembrance marking the start of Japan's invasion. "But we made progress much faster than we expected."

Within just two weeks, they had gathered the first batch of relics related to Unit 731's war crimes.

The initiative does not end there. Xu and his friends are preparing a second donation for Dec 13 — China's National Memorial Day for Nanjing Massacre Victims. They also intend to allocate about 30 percent of their annual disposable income to the long-term collection of evidence linked to Unit 731.

Xu has been documenting the project's progress on social media, where his video series has garnered nearly 200,000 likes.

His efforts have received widespread support and praise from peers, with many describing him as someone with "a strong sense of justice" and "noble integrity".

For Xu, the project is a way to uphold both national memory and human dignity. "We must remember our nation's painful history — not to fuel hatred or spread negativity," he said. "Our goal is to never forget where we came from and to safeguard the moral foundation of civilization and humanity."

shanshuo@i21st.cn