TOKYO, Sept. 19 (Xinhua) -- "Although history is in the past, if it cannot be faced up to or be known, then the facts will hardly transform into profound lessons to avoid repeating the same mistakes," said Seiya Matsuno, a researcher at Meiji Gakuin University's International Peace Research Institute in Japan.

Matsuno, who as a scholar of Japanese modern and contemporary history has dedicated himself to studying the activities of the Japanese Imperial Army's Unit 731 in China at his own expense, reiterated the importance of Japanese society acknowledging its wartime history and spreading the truth in an exclusive interview with Xinhua in Tokyo.

To cover up the heinous crimes committed by Unit 731 in China, the Japanese military burned and destroyed relevant documents. "Even now, we can find the original copies of orders issued by the Japanese Imperial Army General Staff Office before their defeat, instructing Unit 731 to urgently and thoroughly destroy all documents," Matsuno revealed.

"As of now, most of the information about Unit 731, its composition, and activities comes from testimonies of former members and confessions of Japanese war criminals during the 1949 Khabarovsk War Crimes Trials in the Russian Far Eastern city," said the researcher. "There are very few first-hand materials left."

However, while many Unit 731 documents in China were destroyed, some were retained in Japan or brought back from China during the war, according to Matsuno.

Among these records, Matsuno recently discovered documents including the "Staff List of Top Officials in the Epidemic Prevention and Water Purification Department of the Kwantung Army," listing the names and ranks of members of the notorious germ warfare army Unit 731 that killed thousands of Chinese civilians and Russian prisoners of war at its sprawling complex in the northeastern Chinese city of Harbin during World War II (WWII).

These documents fill gaps in research regarding the initial organization and size of Unit 731, enhancing the evidential chain related to the unit's war crimes. However, finding these historical materials was no easy task for the Japanese researcher.

According to Matsuno, Japan's WWII-related records have been transferred to the National Archives of Japan (NAJ) by the Ministry of Health, Labor, and Welfare, while some diplomatic and military-related documents are kept by the Ministry of Foreign Affairs and the Ministry of Defense.

Every once in a while, the NAJ would release batches of newly processed historical materials, among which Matsuno spotted the recently discovered documents.

The researcher pointed out that even when new materials are made available, they can remain obscure without substantial expertise and research skills, as searching for information using keywords like "Unit 731" or "epidemic prevention unit" yields little results.

Additionally, accessing sensitive content at the NAJ comes with various restrictions, such as "no lending, no copying, no photography," making it difficult for researchers to share evidence with the public, said Matsuno.

When it comes to the personal information of Japanese military personnel, Japan often cites "protecting individual privacy" as a reason to impede researchers. Unless one is a direct relative, access to such information is typically denied. "Currently, nobody knows how many unprocessed historical materials remain at the NAJ," Matsuno noted.

"This list clearly shows that there were at least 1,129 vacant positions in Unit 731 due to reorganization and expansion. Despite the severe shortage of personnel, the general staff office still ordered the unit to carry out bacteriological warfare in places like Ningbo and Quzhou in China's Zhejiang Province," he said.

This document also exposed a lie told by a key war criminal named Naeo Ikeda. In the 1980s, Keio University professor Takao Matsumura and several other scholars discovered a first-hand report authored by "Major Ikeda" as the person in charge, which documented skin injuries and deaths of prisoners resulting from the use of poison gas by Unit 731 in Heilongjiang.

When confronted with this report, Ikeda, who was alive at the time, denied involvement, claiming that he "was not serving at Unit 731 in 1940 and could not have participated in such experiments." However, his name now appears on the staff list as the only individual surnamed Ikeda. This revelation confirmed that Ikeda was responsible for poison gas experiments conducted by Unit 731.

Matsuno explained that newly-discovered documents that listed names and ranks of senior officers and staff at another Imperial Japanese Army facility called the Kwantung Army Warhorse Disease Prevention Factory, pertained to the activities of Japan's Unit 100, another germ warfare army often referred to as the "Evil Brothers" alongside Unit 731.

Historical materials related to Unit 100 have been scarce, making these documents vital for further understanding the war crimes committed by the Japanese Imperial Army in China.

"Discovering more historical materials brings us closer to the true and complete history," Matsuno remarked. "In the future, I will continue to explore more historical truths and share them with as many people as possible. We must not allow such human tragedies to happen again, and this is the important responsibility of historians like us."