Son retraces father's untold wartime past in secret germ unit

Asahi Shimbun

14-06-2025

In this undated photo, men who are believed to be members of an Imperial Japanese Army biological warfare unit work in China. The photo was found in Katsutoshi Takegami's home in Nagano Prefecture. (Provided by Katsutoshi Takegami)
Katsutoshi Takegami's curiosity was piqued when he discovered a wooden box containing a large number of old photos showing his late father in his wartime military uniform along with his comrades.
Takegami found the cache seven years ago in his home in Komagane, a city in Nagano Prefecture, in central Japan.
The photos also included those of men working in the vicinity of a well and on the riverbank as well as a sign that read 'Epidemic Prevention Section's Workroom.'
Takegami, 77, said his father, Toshiichi Miyashita, barely spoke about his wartime experiences during his lifetime.
'I did water certification work' during the war, he recalled his father saying, but not much else.
But the old photos aroused Miyashita's interest to find out more about his father's military service.
CONNECTED TO INFAMOUS UNIT 731
Takegami contacted the Ministry of Health, Labor and Welfare for his father's military records.
The ministry keeps records on rosters of Imperial Japanese Army troops at the time of 1945.
The ministry's documents showed that Miyashita belonged to the army's Epidemic Prevention and Water Supply Department in central China.
Takegami initially had no idea what that entailed.
He came across a brief reference that the department, which is known as Unit 1644, essentially worked with Unit 731 like 'two sides of the same coin' when he scoured books for a hint.
Takegami was flabbergasted by the revelation.
He had not been particularly interested in the Japanese military's wartime activities and his knowledge of the conflict was limited.
Still, he knew of the notorious reputatation of Unit 731.
The unit, based in Harbin in northeastern China, where Japan founded its puppet state of Manchukuo (1932-1945), conducted grisly experiments on humans by live dissections, infections with deadly pathogens, including plague, typhus and cholera, and by many other cruel methods.
The unit developed and tested biological weapons on Chinese cities.
Books have been published, documentaries made and exhibitions held to detail the atrocities committed by the unit based on volumes of records and accounts by former members and witnesses.
However, little is known about the army's other germ warfare units including the one in which Takegami's father served.
ROSTER RECENTLY DECLASSIFIED
Unit 1644, headquartered in Nanking in central China, remains shrouded in secrecy 80 years after the end of World War II.
Recently, however, the National Archives of Japan declassified a roster of the unit.
This newly released information offers hope to historians, that it might provide clues to help uncover some of its activities and the army's vast network of biological warfare units deployed across China.
Takegami could not believe that his father served in a unit that was described as having close ties to Unit 731.
PERSONAL ITEMS OFFERED CLUE TO HIS PAST
After he returned to Japan after the war, Miyashita worked for a public health center.
Takegami remembered his father as a dedicated worker.
He woke up early to mow their farm's grass before going to work, occasionally enjoying drinking, but never got drunk. He did not take up any particular hobby, but just contented himself with doing his job.
Takegami grew increasingly curious about his father's mysterious past. But as a pensioner, he had limited economic means to conduct an extensive search.
Still, he collected academic papers and expensive specialized books that had been out of print as he searched for clues to discern the secrets of Unit 1644.
His father was born in Iijima town in Nagano Prefecture in 1909.
After Miyashita was conscripted by the army when he was 21, he was first sent to the northeast region of China, what was then known as Manchuria, as a medical assistant.
After some transfers, Miyashita was posted to Unit 1644 in 1939, when it was founded in Nanking, according to the military records.
A close scrutiny of his records also revealed that he participated in 1942 and 1943 campaigns in southern China where the army waged biological warfare by airborne spraying of plague and cholera germs into the local population.
The finding brought back childhood memories to Takegami that might have reflected his father's work during the war.
There were large numbers of syringes in their home that Miyashita had brought from the war.
When Takegami broke one of the devices while making an insect specimen, he was scolded by his father. He once asked him what he did in the war.
Miyashita's reply was curt and angry.
'I have seen people die in front of my eyes many times,' his father said. 'I will not talk about the war lightly.'
The records also showed that Miyashita was promoted to the rank of medical lieutenant, starting from the bottom rung as a medical private.
Takegami recalled his father remarking one day with a pride: 'It was rare for a private to get promoted to the rank of lieutenant.'
But exactly what he did to earn the promotion in a germ warfare unit remained an unsolved mystery for Takegami.
UNLOCKING SECRETS OF UNIT 1644
Some historians call Unit 1644 an 'elite' group next to Unit 731 in the army's units developing biological weapons.
Testimonies and documentation related to Unit 1644, however, are rare.
Many researchers refer to the possibility that most documents associated with Unit 1644, or other germ warfare units for that matter, were destroyed upon Japan's defeat, citing eyewitness accounts that said that relevant records were burned.
One of the few references to the unit came from the late Shigeo Ban, a former member of the top-secret Noborito Laboratory, the army's research institute in Kanagawa Prefecture to develop secret weapons and intelligence operations.
In his memoir, Ban recalled a 1941 trip to Nanking during which he witnessed military doctors from Unit 1644 performing experiments on live Chinese prisoners of war.
To put out word about his search, Takegami offered his father's pictures to a scholar researching medicine practiced in Manchuria and Japan's other former colonies.
The material was published in a book last year titled 'Teikoku Rikugun Boeki Kyusuibu Bijuaru Shashincho -- 731-Butai Shimai Kikan 'Sakae 1644 Butai' in Kyuzo' (Photobook of Imperial Japanese Army's Epidemic Prevention and Water Supply Department–possessed by a member of Unit 1644, a sister unit of Unit 731).
'I was hoping that some readers might contact me to share information leading to my father,' Takegami said.
In the course of his research, he learned that documents on names and addresses of Unit 1644 members were kept by the health ministry and that the documents were handed over to the National Archives of Japan last year for eventual disclosure.
When they were made available to the public, Takegami quickly applied for access and shared them with researchers investigating the biological warfare units.
Takegami is aware that the disclosed data may not immediately shed light on his father's footsteps.
But he is pinning his hopes on eventually uncovering some information if he can locate and interview descendants of other members of the unit.
'In my search, I have sometimes faced such questions as why I am still driven to help expose the activities of the unit,' Takegami said. 'Eighty years on, our memories of the war are fading fast. But I am determined not to let my father's wartime deeds and Unit 1644's activities be buried as a mystery.'
Katsuo Nishiyama, a professor emeritus at Shiga University of Medical Science who went through the declassified information with Takegami, noted the records, disclosed on May 14, contained the rosters of Unit 1644 and Unit 8604, which was based in Guangzhou in southern China.
Nishiyama said that the list of Unit 1644 members includes names that also appear in Unit 731 records, evidence he believes validates the close collaboration between the two entities.
'The released rosters will enable us to track down its members and unearth previously unknown accounts, hopefully advancing studies to unravel the Imperial Japanese Army's extensive network of germ warfare units,' Nishiyama said.