Surgeon General
Surgeon general (: surgeons general) is a title used in several Commonwealth countries and most NATO nations to refer either to a senior military medical officer or to a senior uniformed physician commissioned by the government and entrusted with p ...
was a Japanese
microbiologist
A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of microscopic organisms such as bacteria, algae, fungi, and some types of par ...
and
army medical officer, who served as the director of
Unit 731
, short for Manchu Detachment 731 and also known as the Kamo Detachment and the Ishii Unit, was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentat ...
, a
biological warfare
Biological warfare, also known as germ warfare, is the use of biological toxins or Pathogen, infectious agents such as bacteria, viruses, insects, and Fungus, fungi with the intent to kill, harm or incapacitate humans, animals or plants as an ...
unit of the
Imperial Japanese Army
The Imperial Japanese Army (IJA; , ''Dai-Nippon Teikoku Rikugun'', "Army of the Greater Japanese Empire") was the principal ground force of the Empire of Japan from 1871 to 1945. It played a central role in Japan’s rapid modernization during th ...
. Ishii led the development and application of
biological weapon
Biological agents, also known as biological weapons or bioweapons, are pathogens used as weapons. In addition to these living or replicating pathogens, toxins and Toxin#Biotoxins, biotoxins are also included among the bio-agents. More than 1,2 ...
s at Unit 731 in
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
during the
Second Sino-Japanese War
The Second Sino-Japanese War was fought between the Republic of China (1912–1949), Republic of China and the Empire of Japan between 1937 and 1945, following a period of war localized to Manchuria that started in 1931. It is considered part ...
from 1937 to 1945, including the
bubonic plague
Bubonic plague is one of three types of Plague (disease), plague caused by the Bacteria, bacterium ''Yersinia pestis''. One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and ...
attacks at Chinese cities of
Changde
Changde (; Traditional Chinese characters, traditional Chinese: 常德區 ) is a prefecture-level city in the northwest of Hunan province, People's Republic of China. Changde, known as "Wuling" in ancient times, is located on the west side of Do ...
and
Ningbo
Ningbo is a sub-provincial city in northeastern Zhejiang province, People's Republic of China. It comprises six urban districts, two satellite county-level cities, and two rural counties, including several islands in Hangzhou Bay and the Eas ...
, and planned the
Operation Cherry Blossoms at Night biological attack against the United States.
Hirohito
, Posthumous name, posthumously honored as , was the 124th emperor of Japan according to the traditional order of succession, from 25 December 1926 until Death and state funeral of Hirohito, his death in 1989. He remains Japan's longest-reigni ...
rewarded him with a special service medal for his work.
Ishii and his colleagues also engaged in
human experimentation
Human subject research is systematic, scientific investigation that can be either interventional (a "trial") or observational (no "test article") and involves human beings as research subjects, commonly known as test subjects. Human subject r ...
, resulting in the deaths of over 10,000 subjects, most of them civilians or prisoners of war.
Biography
Early years
Shirō Ishii was born in , now
Shibayama, in
Chiba Prefecture
is a Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Chiba Prefecture has a population of 6,278,060 (1 June 2019) and has a geographic area of . Chiba Prefecture borders Ibaraki Prefecture to the north, Saitama ...
,
Japan
Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
, the fourth son of Katsuya Ishii, a wealthy landowner and
sake
Sake, , or saki, also referred to as Japanese rice wine, is an alcoholic beverage of Japanese origin made by fermenting rice that has been polished to remove the bran. Despite the name ''Japanese rice wine'', sake, and indeed any East Asi ...
maker. The Ishii family was the community's largest landholder and exercised a feudal dominance over the local village and surrounding hamlets. Ishii attended the Chiba Middle School (now Chiba Prefectural Chiba High School) in
Chiba City and the
Fourth Higher School (now
Kanazawa University), a
higher school in
Kanazawa
is the capital of Ishikawa Prefecture in central Japan. , the city had an estimated population of 466,029 in 203,271 households, and a population density of 990 persons per km2. The total area of the city was .
Etymology
The name "Kanazaw ...
,
Ishikawa Prefecture
is a Prefectures of Japan, prefecture of Japan located in the Chūbu region of Honshu island. Ishikawa Prefecture has a population of 1,096,721 (1 January 2025) and has a geographic area of 4,186 Square kilometre, km2 (1,616 sq mi). Ishikawa Pr ...
. Some of his classmates regarded him as brash, abrasive and arrogant. His daughter Harumi felt that Shiro had been "unjustly condemned", saying "my father was a very warm-hearted person...he was so bright that people sometimes could not catch up with the speed of his thinking and that made him irritated, and he shouted at them." In 1916, Ishii enrolled at Faculty of Medicine,
Kyoto Imperial University. He graduated in 1920, and married the daughter of Akari Torasaburō, the university's president, in the same year.

In 1921, Ishii was commissioned into the
Imperial Japanese Army
The Imperial Japanese Army (IJA; , ''Dai-Nippon Teikoku Rikugun'', "Army of the Greater Japanese Empire") was the principal ground force of the Empire of Japan from 1871 to 1945. It played a central role in Japan’s rapid modernization during th ...
as a
military surgeon with the rank of Army Surgeon, First Class (surgeon lieutenant). In 1922, Ishii was assigned to the 1st Army Hospital and Army Medical School in
Tokyo
Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...
, where his work impressed his superiors enough to enable him to return to Kyoto Imperial University to pursue
post-graduate
Postgraduate education, graduate education, or graduate school consists of academic or professional degrees, certificates, diplomas, or other qualifications usually pursued by post-secondary students who have earned an undergraduate (bachelor' ...
medical schooling in 1924. During his studies, Ishii would often grow bacteria "pets" in multiple petri dishes, and his odd practice of raising bacteria as companions rather than as research subjects made him notable to the staff of the university.
He did not get along well with his classmates; they would become infuriated as a result of his "pushy behaviour" and "indifference". One of his mentors, Professor Ren Kimura, recalled that Ishii had an odd habit of doing his laboratory work in the middle of the night, using laboratory equipment that had been carefully cleaned by his classmates earlier. His classmates would "really be mad when they came in and found the laboratory equipment dirty the next morning".
In 1925, Ishii was promoted to Army
Surgeon
In medicine, a surgeon is a medical doctor who performs surgery. Even though there are different traditions in different times and places, a modern surgeon is a licensed physician and received the same medical training as physicians before spec ...
, Second Class (surgeon captain).
Biological warfare project
By 1927, Ishii was advocating for the creation of a Japanese
bio-weapons program, and in 1928 began a two-year tour of the West, where he did extensive research on the effects of
biological warfare
Biological warfare, also known as germ warfare, is the use of biological toxins or Pathogen, infectious agents such as bacteria, viruses, insects, and Fungus, fungi with the intent to kill, harm or incapacitate humans, animals or plants as an ...
and
chemical warfare developments from
World War I
World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
onwards. Ishii's travels were highly successful and helped win him the patronage of
Sadao Araki
Baron was a general in the Imperial Japanese Army before and during World War II. As one of the principal nationalist right-wing political theorists in the Empire of Japan, he was regarded as the leader of the radical faction within the polit ...
, the Japanese
Minister of the Army. Ishii also received the backing of Araki's ideological rival in the army, Major-General
Tetsuzan Nagata, who was later considered Ishii's "most active supporter" at the
Khabarovsk War Crime Trials. In January 1931, Ishii received promotion to Senior Army Surgeon, Third Class (surgeon major). According to Ishii's followers, Ishii was extremely loyal to the
Emperor
The word ''emperor'' (from , via ) can mean the male ruler of an empire. ''Empress'', the female equivalent, may indicate an emperor's wife (empress consort), mother/grandmother (empress dowager/grand empress dowager), or a woman who rules ...
and had an "enthusiastic personality" and "daring and carefree attitude", with eccentric work habits such as working late at night in the lab after hanging out with friends at town. He was also known for his heavy drinking, womanizing and embezzling habits, which were tolerated by his colleagues. Ishii was described as a vehement nationalist, and this helped him gain access to the people who could provide him funds.

In 1935, Ishii was promoted to Senior Army Surgeon, Second Class (surgeon lieutenant-colonel). On August 1, 1936, Ishii would be given formal control over
Unit 731
, short for Manchu Detachment 731 and also known as the Kamo Detachment and the Ishii Unit, was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentat ...
and its research facilities. A former member of Unit 731 recalled in 1998 that when he first met Ishii in Tokyo, he was surprised at his commander's appearance: "Ishii was slovenly dressed. His uniform was covered with food stains and ashes from numerous cigarettes. His officer's sword was poorly fastened and dragged on the floor". However, in
Manchuria
Manchuria is a historical region in northeast Asia encompassing the entirety of present-day northeast China and parts of the modern-day Russian Far East south of the Uda (Khabarovsk Krai), Uda River and the Tukuringra-Dzhagdy Ranges. The exact ...
, Ishii would transform into a different character: "he was dressed immaculately. His uniform was spotless, and his sword was tied correctly".
As the leader of Unit 731, Ishii conducted a variety of experiments, including vivisections, testing biological weapons on Chinese villages, poisoning by toxins and gases and forcing inmates to inflict syphilis on each other.
Ishii also reportedly showed
Hideki Tojo
was a Japanese general and statesman who served as Prime Minister of Japan from 1941 to 1944 during the Second World War. His leadership was marked by widespread state violence and mass killings perpetrated in the name of Japanese nationalis ...
, who would later become Prime Minister in 1941, films of the experiments over several years. Tojo considered them "unpleasant" and eventually stopped watching them.
Further promotions for Ishii would follow: he was promoted to Senior Army Surgeon, First Class (surgeon colonel) in 1938, Assistant Surgeon General (surgeon
Major General) in March 1941, and Surgeon General (surgeon Lieutenant General) in March 1945.
Emperor Showa rewarded him with a special service medal.
Towards the end of the war, Ishii developed a plan to spread plague fleas along the populated west coast of the US, known as
Operation Cherry Blossoms at Night. This was targeted for September 22 but the plan was not realized due to the surrender of Japan on August 15, 1945. Ishii and the Japanese government attempted to cover up the facilities and experiments, but ultimately failed with their secret university lab in Tokyo and their main lab in
Harbin
Harbin, ; zh, , s=哈尔滨, t=哈爾濱, p=Hā'ěrbīn; IPA: . is the capital of Heilongjiang, China. It is the largest city of Heilongjiang, as well as being the city with the second-largest urban area, urban population (after Shenyang, Lia ...
, China. The Exhibition Hall of Evidences of Crime Committed by Unit 731 of the Japanese Imperial Army (731罪证陈列馆) in Harbin stands as a museum to the unit and the atrocities they committed. Estimates for the number of people killed by
Japanese biological warfare range as high as 300,000. Ishii was later granted immunity in the
International Military Tribunal for the Far East
The International Military Tribunal for the Far East (IMTFE), also known as the Tokyo Trial and the Tokyo War Crimes Tribunal, was a military trial convened on 29 April 1946 to Criminal procedure, try leaders of the Empire of Japan for their cri ...
by the United States government in exchange for information and research for the
U.S. biological warfare program.
War crimes immunity
Ishii was arrested by
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
authorities during the
Occupation of Japan
Japan was occupied and administered by the Allies of World War II from the surrender of the Empire of Japan on September 2, 1945, at the war's end until the Treaty of San Francisco took effect on April 28, 1952. The occupation, led by the ...
at the end of World War II and, along with other leaders, was supposed to be thoroughly interrogated by Soviet authorities.
Instead, Ishii and his team managed to negotiate and receive
immunity
Immunity may refer to:
Medicine
* Immunity (medical), resistance of an organism to infection or disease
* ''Immunity'' (journal), a scientific journal published by Cell Press
Biology
* Immune system
Engineering
* Radiofrequence immunity ...
in 1946 from
Japanese war crimes
During its imperial era, Empire of Japan, Japan committed numerous war crimes and crimes against humanity across various Asian-Pacific nations, notably during the Second Sino-Japanese War, Second Sino-Japanese and Pacific Wars. These incidents ...
prosecution before the
Tokyo tribunal
The International Military Tribunal for the Far East (IMTFE), also known as the Tokyo Trial and the Tokyo War Crimes Tribunal, was a military trial convened on 29 April 1946 to try leaders of the Empire of Japan for their crimes against peace ...
in exchange for their full disclosure. Although the Soviet authorities wished the prosecutions to take place, the United States objected after the reports of a team of military
microbiologists headed by Lieutenant Colonel
Murray Sanders stated that the information was "absolutely invaluable”; it "could never have been obtained in the United States because of scruples attached to experiments on humans" and "the information was obtained fairly cheaply."
On May 6, 1947,
Douglas MacArthur
Douglas MacArthur (26 January 18805 April 1964) was an American general who served as a top commander during World War II and the Korean War, achieving the rank of General of the Army (United States), General of the Army. He served with dis ...
wrote to Washington that "additional data, possibly some statements from Ishii probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as 'War Crimes' evidence."
Ishii's immunity deal was concluded in 1948 and he was never prosecuted for any war crimes or crimes against humanity.
After being granted immunity, Ishii was hired by the U.S. government to lecture American officers at
Fort Detrick on the uses of bioweapons and the findings made by Unit 731.
During the
Korean War
The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...
, Ishii reportedly traveled to Korea to take part in the
U.S. Army's alleged biological warfare activities. On 22 February 1952, Ishii was explicitly named in a statement made by
North Korean Foreign Minister
In many countries, the ministry of foreign affairs (abbreviated as MFA or MOFA) is the highest government department exclusively or primarily responsible for the state's foreign policy and relations, diplomacy, bilateral, and multilateral r ...
Pak Hon-yong, claiming that he, along with other "Japanese bacteriological war criminals",
had been involved in "systematically spreading large quantities of bacteria-carrying insects by aircraft in order to disseminate contagious diseases over our frontline positions and our rear".
However, whether the U.S. Army actually used biological weapons against Chinese or North Korean forces, or whether such allegations were mere propaganda, is disputed by historians.
[Endicott, Stephen L.; Hagerman, Edward; ''The United States and Biological Warfare: Secrets from the Early Cold War and Korea'']
Google Books
; Bloomington: Indiana University Press; 1998; pp. 75-77; ; retrieved 7 January 2009.[Weathersby, Kathryn; Leitenberg, Milton]
"New Evidence on the Korean War"
; '' Cold War International History Project''; Wilson Center; 1998; retrieved 4 March 2011.
After returning to Japan, Ishii opened a clinic, performing examinations and treatments for free.
He kept a diary, but it did not make reference to any of his wartime activities with Unit 731.
Death

In his last years, Ishii could not speak clearly; he was uncomfortable and on pain medication, speaking in a harsh voice. He died on October 9, 1959, from
laryngeal cancer
Laryngeal cancer is a kind of cancer that can develop in any part of the larynx (voice box). It is typically a squamous-cell carcinoma, reflecting its origin from the epithelium of the larynx.
The prognosis is affected by the location of the tumo ...
at the age of 67 at a hospital in
Shinjuku
, officially called Shinjuku City, is a special ward of Tokyo, Japan. It is a major commercial and administrative center, housing the northern half of the busiest railway station in the world ( Shinjuku Station) as well as the Tokyo Metropol ...
, Tokyo. Ishii's funeral was chaired by
Masaji Kitano, his second-in-command at Unit 731.
According to his daughter, Ishii became a
Roman Catholic
The Catholic Church (), also known as the Roman Catholic Church, is the largest Christian church, with 1.27 to 1.41 billion baptized Catholics worldwide as of 2025. It is among the world's oldest and largest international institut ...
shortly before his death.
Ishii's daughter, Harumi Ishii, recalled in an interview
that shortly before his death, Ishii's medical condition worsened:
In media
Ishii was portrayed by Min Ji-hwan in the
MBC TV series ''
Eyes of Dawn'', and portrayed by Gang Wang in the 1988 film ''
Men Behind The Sun''.
In the grimdark fantasy novel, ''
The Poppy War'', which mirrors the Second Sino-Japanese War, a fictional counterpart of Ishii, named Shiro, performs human experiments in a concentration camp similar to Unit 731.
See also
*
Josef Mengele
Josef Mengele (; 16 March 19117 February 1979) was a Nazi German (SS) officer and physician during World War II at the Russian front and then at Auschwitz during the Holocaust, often dubbed the "Angel of Death" (). He performed Nazi hum ...
*
Operation Paperclip
The Operation Paperclip was a secret United States intelligence program in which more than 1,600 German scientists, engineers, and technicians were taken from former Nazi Germany to the US for government employment after the end of World War I ...
*
Khabarovsk War Crime Trials
*
Nobusuke Kishi
was a Japanese bureaucrat and politician who served as Prime Minister of Japan, prime minister of Japan from 1957 to 1960. He is remembered for his exploitative economic management of the Japanese puppet state of Manchukuo in China in the 1930s, ...
Sources
Citations
References
* Barenblatt, Daniel. ''A Plague Upon Humanity: the Secret Genocide of Axis Japan's Germ Warfare Operation'', HarperCollins, 2004.
* Gold, Hal. ''Unit 731 Testimony'', Charles E Tuttle Co., 1996.
* Williams, Peter and Wallace, David. ''Unit 731: Japan's Secret Biological Warfare in World War II'', Free Press, 1989.
* Harris, Sheldon H. ''Factories of Death: Japanese Biological Warfare 1932–45 and the American Cover-Up'', Routledge, 1994.
* Endicott, Stephen and Hagerman, Edward. ''The United States and Biological Warfare: Secrets from the Early Cold War and Korea'', Indiana University Press, 1999.
* Handelman, Stephen and Alibek, Ken. ''Biohazard: The Chilling True Story of the Largest Covert Biological Weapons Program in the World – Told from Inside by the Man Who Ran It'', Random House, 1999.
* Harris, Robert and Paxman, Jeremy. ''A Higher Form of Killing: The Secret History of Chemical and Biological Warfare'', Random House, 2002.
* Barnaby, Wendy. ''The Plague Makers: The Secret World of Biological Warfare'', Frog Ltd, 1999.
* Yang Yan-Jun and Tam Yue-Him. ''Unit 731: Laboratory of the Devil, Auschwitz of the East: Japanese Biological Warfare in China 1933-45''. Fonthill Media, 2018.
{{DEFAULTSORT:Ishii, Shiro
1892 births
1959 deaths
Imperial Japanese Army generals of World War II
Japanese military doctors
Japanese Christians
Japanese human subject research
Japanese biological weapons program
Japanese war criminals
Japanese Roman Catholics
Members of the Kwantung Army
Military personnel from Chiba Prefecture
Converts to Christianity
Kyoto University alumni
Deaths from esophageal cancer in Japan
Combat medics
People related to biological warfare
Scientists from Chiba Prefecture