Unit 731
and the Human Skulls Discovered in 1989: Physicians Carrying Out Organized
Crimes
Tsuneishi
Kei-ichi
Brief History
of Unit 731
The Tôgô Unit
Unit 731 was officially inaugurated in the town of Ping Fan (near Harbin)
in China in August of 1936[1]. Preparatory activities were already
underway in the fall of 1932, however, in a shoyu [soy sauce] factory in a small
village about 100 kilometers southeast of Harbin[2]. In that year (1932), Ishii
Shirô, the man who
would later become the head of Unit 731, launched and became the director of the
Army Medical College’s Epidemic
Prevention Research Laboratory (EPRL) in Tokyo[3]. For the next year, besides the official
activities in EPRL, Ishii was heading up the construction of the unit
headquarters in China. Experiments
on human beings began in the fall of 1933 as an inner activity within the Kantô
Army[4]. The researchers who participated in
these operations were all military physicians and each used an alias. This unit was called by the code name
Tôgô, after the alias Ishii used at that time. The use of aliases was indicative of how
much importance they attached to maintaining the secrecy of their
activities.
EPRL was the
control center and the Tôgô Unit (as well as its successors such as Unit 731 and
related units) would carry out its commands—including experiments on
humans. Another key function of the
Laboratory was to serve as a link between civilian research facilities and
military ones such as Unit 731.
Two factors contributed to the necessity of maintaining secrecy about
operations during the three years after 1933. One factor was that they wanted to hide
the purpose of the unit’s organization:
they were performing experiments on humans. The second factor was that, because this
facility was doing research on human beings as part of a feasibility study, the
responsibility would not extend to the emperor if they either failed or were
found out. Failures on the part of
the Emperor’s military would tarnish the image of the Emperor’s infallibility,
and for members of Japan’s army at that time such a thing was
impermissible.
The aim of the feasibility study for conducting experiments on humans had
two aspects:
(1) To find
the possibility of the continuous procurement of test subjects and determine
whether the continuous experimentation on humans was
possible.
(2)
To make sure
that Ishii’s project--experiments on humans for the development of biological
weapons--was worthwhile.
Experiments to inoculate people against the illness associated with
anthrax germs were already being carried out in the operations up to 1936. Of greater note were the methodical
experiments on humans with cyanide.
Approximately 10 people were subjected to these experiments each time
they were performed[5].
Six times from 1934 to 1936, the project directors had the test subjects
drink cyanide and observed the circumstances leading to their deaths. The
following procedures
were characteristic of these cyanide experiments on
humans:
(1)
Photographs were taken.
(2)
Autopsies were performed.
(3)
Verification of a lethal dose was noted.
(4) The
cyanide was mixed with beer, wine or coffee.
(5) The
subjects were Russian spies (derogatorily known as Russkii’s) as well as spies
that the Special Service Agency used and deemed no longer
necessary.
Steps 1-3 show that experiments were performed not for murdering the
victims, but perusing some “medical” purposes. The motivation for procedure 4 was to
make the subjects drink the difficult-to-swallow cyanide without any resistance
and without causing them any apprehension about being made to drink a toxic
substance. The use of spies—step
5--indicates that the procurement of test subjects thought to have begun after
Unit 731 was established actually began during the period of the Tôgô
Unit.
The medical objectives of the cyanide experiments were, except for
procedure 3, to determine the effect murder by cyanide had on the human
body. We can surmise this from the
testimony of Okamoto Kôzô[6],
a scholar of pathology from Kyoto University, at an investigative council held
in July of 1948.
The unit
physicians inoculated about 15 prisoners at one time. In order to study the
conditions of the patients’ illness they murdered them on 3rd day,
4th day, and so on after its onset and before death, and then
performed autopsies on the corpses.
The bodies had most likely been poisoned with potassium cyanide since the
cause of death was suffocation, but because Okamoto was only directly to perform
research on the subjects after they were dead, he had no idea who these poisoned
criminals were.
Cyanide was
not the only substance used; other researchers used chloroform. Onodera Yoshio, who had performed
experiments on humans in Unit 1644 in Nanjing, provided the following testimony
on July 24[7]:
We performed
studies on approximately 100-150 people.
Satô Shunji analyzed the logs [term used to refer to human
subjects—Editor] and Onodera performed research on the developmental conditions
of tuberculosis. In the end we
injected them with chloroform and put them to sleep. They died from the injection. During his tenure there, they did not
use potassium cyanide. (underline
in the original text-Ed)
In 1947, Kasahara Shirô, who performed experiments on humans who had
epidemic hemorrhagic fever (EHF, now called hemorrhagic fever with renal
syndrome) in Unit 731, responded to an American inquiry about this by saying
that “he put them to sleep with chloroform.”[8]
Some physicians murdered their victims with potassium cyanide, and then
dissected them, while others used chloroform. It may be assumed that these different
approaches were due to the experiments’ objectives. We can surmise that the reason they
performed potassium cyanide experiments to such an extent when the Unit was
first created was that they were looking for a method to murder their test
subjects which, before beginning their real research, would not contradict the
medical data. Scrupulous precautions are a requirement of all research, but how
should we judge the scrupulosity shown in these instances—cases where the goal
is the opposite of usual research?
It is obvious how extremely narrow the perspective of these “specialized
fools” had become. But this
circumstance is also emblematic of how frightening it is when researchers go
deeper and deeper into the particulars of their work while becoming more and
more distant from what is common sense in ordinary society.
Official Start of Unit 731
In August, 1936 Unit 731 was created as a formal unit of the Japanese
army and the Tôgô Unit ceased to exist.
The center of operations was moved to facilities built about 30
kilometers south of Harbin. These
facilities not only had medical research and experimentation rooms but were also
furnished with places for interning test subjects, that is a jail (wards 7 and
8). The research and
experimentation rooms were built to surround the jail and the researchers
performed their daily research while watching over the test subjects[9].
There was no change in the level of “scrupulous precaution” after Unit
731 came into existence. The
procurement of test subjects for Unit 731 was entrusted to the military police
and the Special Service Agency.
According to the Unit’s demands, a health exam determined when people
would be sent to the Unit by either[10].
The group in charge of test subjects was headed by physiologist Yoshimura
Hisato who joined the Unit from Kyoto University in 1938. He was called the “Scientific Devil”
within
the Unit. The group Yoshimura
headed was composed of two sections each with two subgroups. One section carried out medical exams
and the other was in charge of supervising prisoners, dispatching prisoners to
experimentation rooms and processing their admission to the Unit. The heads of the two sub-groups in
charge of the medical exams were both physicians. One of those, Miyagawa Tadashi, joined
Unit 731 in April 1944. He was in
charge of X-rays of the test subjects.
After the war he became a professor in Tokyo University’s Medical
Department and lived to the age of 88.
His obituary stated, “Miyagawa led a life that pioneered the medical use
of radiation. He contributed to the
development of the medical use of the cyclotron to treat brain tumors and other
diseases.”[11] The second sub-group was in charge of
blood and immunity exams as well as the health maintenance of test
subjects. Not everyone sent to Unit
731 was subjected to experiments.
These were only carried out on healthy people, and after they were
accepted into the program, the maintenance of their health was a
priority.
Why did Yoshimura become the head of this group? He was a physiologist. Physiology is a
counterpart of pathology, the study
of the etiology of illness. There
were four pathologists in Unit 731.
Their task was to determine whether a prisoner’s cause of death during an
experiment in which he had been infected with a pathogen was actually due to the
pathogen. The field of physiology,
on the other hand, pertains to understanding why a living being is. Yoshimura wrote, “The purpose of a
physiologist’s scholarship is to scientifically explain from a variety of
aspects what the phenomenon of a normal
life is.” (italics in the original)[12]
Physiology is the academic discipline that studies the characteristics of human
health. Therefore, Yoshimura might
take responsibility for departments that controlled wards 7 and
8.
In these wards medical exams were carried out with scientific rigor to
determine how a test subject could finally be killed. However, a rigorously “scientific”
mentality which does not take into account the dignity of its victims as human
beings—which ignores such values—is perverse science. In the case of Unit 731 it is not
difficult to make this judgment; it is not difficult because the perversion of
science in Unit 731 was obvious.
But
recently it seems that a more subtly perverse science is being put before
us. Taking shape in ways more
difficult for us to recognize, it too disregards the value of human beings and
reverses what science should be. An
example is human cloning which masquerades as “therapy for infertile
persons.”
The military
personnel of Unit 731, who were not themselves physicians, referred to Yoshimura
as a “Scientific Devil.” A person who photographed the progress of experiments
on humans testified:[13]
In the spring
of 1944 there were prisoners on the second floor of ward 7. About seventy of them taking keys off a
guard and singing revolutionary songs created quite a disturbance. All of them were killed with gas. Yoshimura, who was in Kobe at the war,
was a scientific devil, a cold-blooded animal.
According to
testimony, many of prisoners were undergoing various experiments, so they made
gas attack to retain experimental data of them. Yoshimura was not only called a
“devil” because of the strictness with which he conducted experiments. He also soaked the fingers of a 3-day
old child in ice water (ice and salt).
There were several hundred prisoners in the jails of Unit 731 in the
summer of 1945 after Japan was defeated.
Every one of them was murdered.
The following testimony describes those circumstances:[14]
On August 11
and 12, after the end of the war approximately 300 prisoners were disposed
of. The prisoners were coerced into
suicide by being given a piece of rope.
One quarter of them hung themselves and the remaining three quarters who
would not consent to suicide were made to drink potassium cyanide and killed by
injection. In the end all were
taken care of. The prisoners were
made to drink potassium cyanide by mixing it with water and putting it into
bowls. The injections were probably
chloroform.
The murdered
people were cremated and buried at the facilities of Unit
731.
The Human
Skulls Discovered in 1989
In July 1989 a great quantity of human bones was discovered in Tokyo at
the construction site for the Ministry of Health and Welfare’s Research Center
for Preventive Hygiene. This area
had been the home of the Army Medical College from 1929 until 1945. The police first announced that bones
were from 35 bodies, but in 1992 Sakura Hajime, an expert involved with the
case, announced that those were from more than 100 bodies[15]. He said the bones were those of people
of Asian descent, but not of just one ethnic group. Several ethnic groups were
intermingled. Moreover, the bones
were not over one hundred years old; they had been there for more than 15
years.
Sakura’s data indicated that the bones found in 1989 were those of
foreigners of Asian descent who had been buried during the period in which the
Army Medical College was located there.
The fact that they were buried did not mean that they had been interred
there formally but that they were hidden to suppress evidence. This was the same method of disposal
used by Unit 731 on murdered test subjects.
The police treated the discovery of the bones as they would any dead body
or bodies by investigating the cause of death and events leading up to it. But a week after the bones were
discovered, the police announced that they uncovered no evidence about the
events surrounding their deaths.
They concluded that even if these people had been victims of a crime,
they had been in the ground for over 15 years and the statute of limitations had
passed. They concluded that the
remains were those of people who had been found dead on the street and disposed
of in this manner.
The truth was different.
Sakura’s investigation made two points clear:[16]
(1) There
were marks on most of the skulls that led him to believe that they had been
severed with a scalpel or a saw during practice brain surgeries at an
experimental stage. The bones had
been in the earth for over fifty years, but in Japan in the 1940’s, brain
surgeries which severed a part of the skull had not yet been
performed.
(2) There
were gashes from a sword on several of the skulls and others had been pierced by
bullets from a pistol.
Sakura’s first point indicated that the skulls had either been used for
experimentation or practice where brain surgeries were performed. The second of Sakura’s points suggested
that they were victims of crimes, at least medical crimes.
There is no direct connection between these experiments or crimes and
Unit 731. What these bones do
indicate is that the barbarism of Unit 731 did not stand out as anything
exceptional among military doctors in Japan. We can presume that these bones
mean that physicians in the Japanese army practiced upon or performed
experiments on the brains of people on the battlefield, or that physicians who
had some relationship with the Army Medical College did, and that the evidence
was destroyed and buried there.
The testimony of Ken Yuasa, an army physician, supports this conjecture[17].
According to Yuasa’s testimony, in order to quickly prepare physicians
trained primarily as internists for the work needed as surgeons on the
battlefield, they were gathered together every few months to perform atrocities
called “surgery drills” on the battlefields of China. They would capture citizens, shoot them
in the thigh with a bullet, and undertake drills to see how long the extraction
of a bullet would take. If someone
were frostbitten, they would perform an operation to sever the frostbitten
part.
These surgery drills were not just limited to one region of the country,
but practiced widely. In most cases
the victims were locals arrested by the military, and delivered to the Army’s
medical division. This indicates
that the surgery drills were not performed according to individual whim but that
the army military division and military police undertook these activities
methodically within the entire army.
It is likely that the skulls obtained from surgery drills were collected
and sent to the Army Medical College under the control of the army
physicians. If this is the case,
the skulls were definitely those of victims of war crimes.
Open
Secret
In my own
research published in 1981, after analyzing research reports from 1943 and 1944
concerning hemorrahagic fever with renal syndrome published by Kitano Masaji
(Ishii’s successor as unit director from August 1942 to May 1945) and other
researchers, I concluded that their results were based on experiments done on
human beings. I substantiated that
Yoshimura performed experiments on humans in his laboratory work on frostbite[18].
It was not difficult to prove their experiments on human beings through analysis
their papers published by themselves. It needed only few medical knowledge. So
any qualified physician could have reached the same conclusions as mine from
those reports.
Kitano contributed to an article about hemorraghic fever with renal
syndrome in publications for the Defense Agency in 1969. He wrote, “Smordentiv was not able to
infect standard experiment animals such as mice, marmots, rabbits, and monkeys
with either the blood or urine of patients. He too performed experiments on humans to
do research on the etiology of diseases.”[19]
(author’s emphasis) Smordentiv was
a Soviet researcher who worked on EHF in 1940s and identified the virus for
experiments on humans. In Kitano’s
1969 recollections, he also confessed
to having performed experiments on humans, as the other researcher had. The results of these reports were
announced in Defense Agency publications in which Kitano did not try to hide that experiments had
been performed on human beings.
In 1968, the year before Kitano’s publication, Ikeda Naeo, a physician
with Unit 731, published his own research in a paper entitled “Experimental
Studies on Epidemic Hemorrhagic Fever: Pediculus Vestimenti and Xenopsylla
Cheopis as Suspected Vectors of the Disease.”[20] According to this report, experiments
having to do with infections were carried out in the Army Hospital in Kokka on
the border between China and the Soviet Union in January 1942. These experiments on humans confirmed
that EHF was carried by lice and fleas to the local people. Five percent of the people who were
infected with the disease died.
This unequivocal report, which admitted that human experiments had been
performed with pathogenic inoculations that can cause death passed the
inspection of referees and was published in a scholarly journal. That experiments on humans had taken
place in Unit 731 was self-evident to Ikeda and to the Association for
Infectious Diseases that accepted his research. It was the acquisition of data difficult
to obtain without human experiments that was important rather than any ethical
issues. But because the research
was never confirmed by recreating the experiments, it was
meaningless.
Yoshimura, the “Scientific Devil” of Unit 731, wrote: “My research during
the war was published in English journals of physiology after the war and
influenced European and American scholars.
Present-day research that evolved from my own is performed not only in
Japan but also in universities and research centers worldwide and has produced
results.”[21] Yoshimura conducted research during the
war at Unit 731 in China on low temperature physiology, including the
elucidation of mechanisms concerned with frostbite. After the war ended, he organized the
Japanese Society of Biometeorology; his China research was the beginning of his
work on how physiology relates to environmental stress.
Articles Yoshimura published in English in the Journal of Japanese
Physiology reported how humans reacted to zero-degree water[22]. The experiments had consisted of soaking
the middle finger of the right hand in zero degree water and then observing the
changes in skin temperature for 30 minutes. Approximately 100 Chinese men and women
between the ages of 15 and 74 were the subjects of these experiments. “Approximately” is Yoshimura’s own word,
which raises doubt about the rigor of the experiments.
Yoshimura’s English article was criticized in newpapers and elsewhere
because of the statement, “We performed experiments by soaking 3-day old infants
in zero-degree water.” Yoshimura
and his fellow researchers responded, “Though detailed studies could not be
attained on children below 6 years of age, some observations were carried out on
babies. ...the reactions were
detected on the 3rd day after birth, and it increased rapidly with the lapse of
days until at last it was nearly fixed after a month or so.” Data was recorded about the
physiological reactions of a child for 30 minutes on the 3rd day,
first month, and a sixth month when the child’s middle finger was soaked in ice
water.
When a reporter from the Osaka office of the Mainichi Shimbun [Newspaper]
contacted Yoshimura by telephone for a report on the infant experiments, he
responded: “Everyone
misunderstands. I’m being
criticized for having done experiments on infant, but this was the child of the
staff of Yakudai (Pharmaceutical College) who had been sent to the Unit. They were experiments to investigate
what kind of physiological reactions take place in the blood vessels when the
skin is touched by cold water and from what point there is resistance to this
and what we can do in this situation.
I used the child of my staff with his own encouragement. The child was not the child of
prisoner.”[23] He then related how excited the staff
all was about this research and that it was their eagerness that allowed them to
offer their child to the experimental body. That Yoshimura said the child he used
for the experiments were not the child of prisoner but the child of his staff
indicates that he was aware that these experiments were not usual
practice.
Should we forgive the parents their excessive enthusiasm in giving their
3-day old infant up to experiments?
What does it mean that these people participated in experiments and did
research as scientists? I don’t
accept Yoshimura’s explanation to the reporter: everything can be forgiven as a
misunderstanding because there was “enthusiasm” for his scientific
research. Yoshimura showed his lack
of understanding in the way he replied to the reporter. All the staff members in Yoshimura’s
account have died and we can no longer ascertain the truthfulness of his
explanations.
If we accept Yoshimura’s claim that the child were not the child of
prisoner, a different problem arises:
why didn’t he use his own children?
According to Yoshimura’s memoirs, Seventy-seven Years in Retrospect, he
had four children. Among those
four, two were born before he went to Unit 731 and two were born while he was at
the Unit. If we follow Yoshimura’s
own logic, the reason he didn’t offer his children to their experiments was
because he was not enthusiastic about his own research.
But the fact of the matter is that Yoshimura did not use his assistants’
child: he used the child of people who had been captured by the
Unit.
The three researchers I have just told you about did not try to hide
their experiments on humans. When I
first began researching Unit 731, I anticipated enormous work exposing these
experiments. However, as we see in
investigating Kitano’s The History of
Army Hygiene During the Greater East Asia War, much can be accomplished with
a little bit of effort; we can say it was easier than expected. We can also say that most of the
researchers in Unit 731 were not involved in a special cover-up about the
experiments in which they took part.
While they have never revealed their crimes to society to criticiz
themselves, they have discussed and revealed various facts within their own
medical field. Consequently, it has
not been difficult to be certain—especially in terms of research pertaining to
EHF and frostbite—-about who did what kind of human
experiments.
Because almost everyone in the Japanese medical world knew about the
experiments on humans in Unit 731[24],
the researchers in the Unit were able to report later on their own work in
medical papers: even after the war,
reports were published that were unmistakably about the results of experiments
on humans, and reminiscences about the Unit were written up in medical
journals. From this we can be
certain that everyone in the Japanese medical community knew about the
experiments of Unit 731.
Organized
Crimes
Even in the 21st century, the Japanese medical community continues to
ignore the barbarism doctors committed between 1930 and 1945. After 1945 the community showed
indifference toward articles published in medical journals based on data
obtained through barbaric practices.
It would be a mistake for us to attribute this solely to the
insensitivity of the Japanese medical community. There is an institutional problem; it is
not just the independent actions of Yoshimura, Okamoto and
others.
For example,
professors from Kyoto University and Tokyo University were the subjects of the
American army’s inquiry into Unit 731’s experiments[25]. These professors were not members of
Unit 731, but they were senior consultants to Ishii’s Tokyo research site,
EPRL. At Ishii’s request, they sent
these students Yoshimura and Okamoto to the Unit, knowing that they would
perform experiments on humans.
The experiments on frostbite
that Yoshimura performed were central to his research at Kyoto University. Ishikawa Tachiomaru, who was dispatched
to the unit at the same time as Yoshimura, wrote: “When an epidemic was raging
in Manchuria’s Nôan area, we performed autopsies on 57 corpses which had been
stricken with the disease. This was
a world record in terms of the number of corpses...”[26] Kiyono Kenji, one of Ishikawa’s
teachers, sent his students with the hope that they would research diseases there with few cases in
Japan.
The truth is that teachers like Kiyono intended for their students to
perform experiments on humans. The
students carried out this barbarism--which couldn’t be done in Japan proper--in
China, Japan’s colony. The wishes
of the teacher were communicated to the students in China through EPRL and the
results of those experiments were sent back to their teacher through the same
channel.
What are we to make of the fact that none of this was a secret in the
medical world but was unknown for so long in the non-medical world? It is possible that people in the
medical world didn’t feel there was a reason to “expose” or “reveal” something
that was not a secret. Even if this
is true, we must strongly denounce the insensitivity of ignoring the highly
unusual nature of performing experiments on humans--experiments hidden from the
non-medical world. Or, to look at
it another way, if the experiments continued to be hidden because of their
unusual nature, this means there
has been no change in the sense of privilege and authority physicians
demonstrate even after they had been informed of the experiments performed on
humans by their fellow physicians.
But once we
look back their activities, we find the probability is great that physicians
have not felt obligation to hide anything in particular about their experiments
on humans during and after the war. It might be the reason to prove human
experimentation in the Unit through papers quite easily. We’re forced to
conclude that though people outside the medical world consider it an act of
atrocity if they were victimized, tested upon or murdered this way, people
within the medical community who do this as everyday work might not consider
these acts to be unusual in any way.
These murderous experiments were performed within a network formed by the
Army’s Unit 731 and the national medical colleges with EPRL as the
mediator. The murderers were the
physicians in the army research facilities, but it was not just the physicians
who received the “benefits” of these acts; it was also the public researchers
who were their teachers. Excuses
for their behavior took the following forms: (1) researchers who actually
dirtied their own hands with these experiments did it for the nation and the
army and (2) their actions contributed to the progress of science and
medicine.
Without consulting anyone, the medical world took upon itself the right
to decide all these things, and forced the “results” of their research on
society. But isn’t this the
situation today as well? I’d like
to emphasize that it’s not a question of research “results” being good or bad,
but rather a societal deficiency in which the medical community determines how
those “results” are achieved. I’m
troubled that we continue to ignore the barbarism of the 20th century
even now in the 21st century. And
I’m concerned that this is an indication that the Japanese medical community is
neglecting its social responsibilities.
This is not just an issue of whether overt barbarism like that which
existed at Unit 731 could possibly occur again, but the fact that we still lack
the means to discover and prevent barbarism in a more subtle form from
occurring.
Translated
from Japanese by Stephen Miller
Revised the
translated text by Tsuneishi Kei-ichi
[1] Brief History of the Kwantung Army Epidemic Prevention and Water Supply Section. On April 6, 1982, this was submitted to the Diet by Ministry of Health and Welfare.
[2] Endo Saburo, I and 15year war with China, Nicchu Shorin Co., 1981
[3] Fifty-year History of the Army Medical College, 1936, Army Medical College
[4] Endo, ibid
[5] Kai’s note; Kai’s notes recorded every day the report by each investigator on Teigin’s (Imperial Bank) case that is a bank robbery incident in Tokyo in January, 1948, by Kai Bunsuke chief of 1st section of investigation of the Metropolitan Police Department. Teigin’s case was an incident in which 12 persons were killed with cyanide and money was taken. The researchers on toxic in the former Japanese Army and members of Unit 731 were suspected. But in August, a painter was arrested and was sentenced to death. He had denied his commitment to Teigin’s case until his death of 95 years in the hospital prison in 1992.
[6] Kai’s Note
[7] op.cit
[8] Hill & Victor Report, Summary Report on B.W. Investigations, December 12, 1947, Edwin V. Hill, Chief, Basic Sciences, Camp Detrick. The other investigator was Joseph Victor.
[9] Interview with Dr. Akimoto Sueo by Tsuneishi, Akimoto had been a member of the unit since 1944 to research on serology without human experimentation and gave up to be a researcher, if he wanted he would be back to Tokyo University, after returning to Japan on account of his regret that he had not been able to be opposite others’ experimentation on human.
[10] Kai’s Note
[11] Mainichi Shinbun (Mainichi News), January 4, 2002
[12] Yoshimura Hisato, Seventy-seven Years in Retrospect (Kijukaiko), Celebration committee for his 77 years old Memoir, 1984
[13] Kai’s Note, and Interviews with Dr. Meguro Masahiko from 1981 to 1988
[14] Kai’s Note
[15] Sakura Hajime, The report of the investigation on human sculls discovered at Toyama (Shinjuku), Shinjuku ward, 1992. Sakura’s investigation was carried out under the commission by Shinjuku ward.
[16] op.cit
[17] Yuasa Ken, Memory never destroyed, 1981, Nicchu Publishing Co., In this book Yuasa confesses his experiences to conduct surgical training on Chinese to kill.
[18] Tuneishi Kei-ichi, Biological warfare unit which disappeared, 1981, Kaimei-sha
[19] Kitano Masaji, On epidemic hemorrhagic fever, The History of Army Hygiene during the Greater East Asia War, vol. 7, Hygiene School of Self Defense Army, 1969
[20] Ikeda Naeo, Experimental Studies on Epidemic Hemorrhagic Fever: Pediculus Vestimenti and Xenopsylla Cheopis as Suspected Vectors of the Disease, Japanese Journal of Infectious Diseases, 1968, vol.42, No 5, pp.125-130
[21] Yoshimura, Seventy-seven Years in Retrospect
[22] Yoshimura Hisato and Iida Toshiyuki, Studies on the Reactivity of Skin Vessels to Extreme Cold, Japanese Journal of Physiology. Part 1, 1950. Part 2, 1952. Part 3, 1952
[23] Tsuneishi Kei-ichi and Asano Tomizo, Biological warfare unit and two physicians who committed suicide, 1982, Shincho-sha
[24] Naito Ryoichi, Report of Investigation Division, Legal Section, GHQ, SCAP, April 4, 1947
[25] Hill & Victor Report
[26] Ishikawa Tachiomaru, On Plague, Japanese Journal of Pathology, vol.34, No.1 & 2, 1944