was a general in 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 ...
, commanding Japanese ground forces in China 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 ...
and
Pacific War
The Pacific War, sometimes called the Asia–Pacific War or the Pacific Theatre, was the Theater (warfare), theatre of World War II fought between the Empire of Japan and the Allies of World War II, Allies in East Asia, East and Southeast As ...
. In 1948, he was
sentenced to death
Capital punishment, also known as the death penalty and formerly called judicial homicide, is the state-sanctioned killing of a person as punishment for actual or supposed misconduct. The sentence ordering that an offender be punished in s ...
by a military commission for
Yokohama War Crimes Trials due to his direct
command responsibility
In the practice of international law, command responsibility (also superior responsibility) is the legal doctrine of hierarchical accountability for war crimes, whereby a commanding officer (military) and a superior officer (civil) are legally r ...
for
vivisection
Vivisection () is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as a pejorative catch-all term for Animal test ...
and other human medical experiments performed at the
Kyushu Imperial University on downed
Allied airmen.
Biography
Yokoyama was born 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 ...
as the son of a colonel in the Imperial Japanese Army; however, the Yokoyama clan was originally from what is now
Fukushima Prefecture
is a Prefectures of Japan, prefecture of Japan located in the Tōhoku region of Honshu. Fukushima Prefecture has a population of 1,771,100 () and has a geographic area of . Fukushima Prefecture borders Miyagi Prefecture and Yamagata Prefecture ...
, where they were
samurai
The samurai () were members of the warrior class in Japan. They were originally provincial warriors who came from wealthy landowning families who could afford to train their men to be mounted archers. In the 8th century AD, the imperial court d ...
in service of
Aizu Domain
was a Han (Japan), domain of the Tokugawa Shogunate of Japan during the Edo period from 1601 to 1871.Ravina, Mark. (1998) ''Land and Lordship in Early Modern Japan,'' p. 222
The Aizu Domain was based at Aizuwakamatsu Castle, Tsuruga Castle in M ...
. He attended military preparatory schools in
Himeji
260px, Himeji City Hall
is a city located in Hyōgo Prefecture in the Kansai region of Japan. , the city had an estimated population of 525,682 in 227,099 households and a population density of 980 persons per km2. The total area of the city is ...
and
Osaka
is a Cities designated by government ordinance of Japan, designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the List of cities in Japan, third-most populous city in J ...
and graduated from the 21st class of the
Imperial Japanese Army Academy
The was the principal officer's training school for the Imperial Japanese Army. The programme consisted of a junior course for graduates of local army cadet schools and for those who had completed four years of middle school, and a senior course f ...
in December 1909. He served with the IJA 3rd Infantry Regiment as a junior officer. He graduated from the 27th class of the
Army Staff College in December 1915.
In his early career, Yokoyama served in the
Imperial Japanese Army General Staff Office
The , also called the Army General Staff, was one of the two principal agencies charged with overseeing the Imperial Japanese Army (IJA).
Role
The was created in April 1872, along with the Navy Ministry, to replace the Ministry of Military Af ...
and at the
Army Ministry
The , also known as the Ministry of War, was the cabinet-level ministry in the Empire of Japan charged with the administrative affairs of the Imperial Japanese Army (IJA). It existed from 1872 to 1945.
In the IJA and the Imperial Japanese Navy ...
. From January 1925 to March 1927 he was assigned as a
to
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
. On his return, he again served in various bureaucratic posts involved in military production and resources planning. After his promotion to lieutenant colonel in 1929, he served as chief of the 2nd Section of the Cabinet Planning Board. He was transferred to the staff of the
Kwantung Army
The Kwantung Army (Japanese language, Japanese: 関東軍, ''Kantō-gun'') was a Armies of the Imperial Japanese Army, general army of the Imperial Japanese Army from 1919 to 1945.
The Kwantung Army was formed in 1906 as a security force for th ...
in April 1932, and was promoted to colonel in August of the same year. After serving as chief of the Mobilization Section, Economic Mobilization Bureau at the Ministry of War in 1933, Yokoyama served as battalion commander of the IJA 2nd Regiment in 1934 and was promoted to the staff of the
IJA 6th Division in 1936. In March 1937, he was promoted to
major general.
A specialist in resources allocation, Yokoyama was appointed Head of the Planning Bureau of the Cabinet Resources Board in 1937. He was promoted to lieutenant general in August 1939. In September of the same year, he returned to
Manchukuo
Manchukuo, officially known as the State of Manchuria prior to 1934 and the Empire of Great Manchuria thereafter, was a puppet state of the Empire of Japan in Northeast China that existed from 1932 until its dissolution in 1945. It was ostens ...
as commander of the
IJA 1st Division
The was an infantry division in the Imperial Japanese Army. Its ''tsūshōgō'' was the . The 1st Division was formed in Tokyo in January 1871 as the , one of six regional commands created in the fledgling Imperial Japanese Army. The Tokyo Garr ...
. In October 1941, he was promoted to commander of the
IJA 4th Army, which was based at
Bei'an, the capital of a northern Manchukuo province of the same name, that was heavily fortified with various ground emplacements against possible incursions by the Soviet
Red Army
The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Republic and, from 1922, the Soviet Union. The army was established in January 1918 by a decree of the Council of People ...
. From 21 December 1942, he was commander of the
IJA 11th Army, which was in combat at the
Battle of Changde
The Battle of Changde (Battle of Changteh; ) was a major engagement in the Second Sino-Japanese War in and around the Chinese city of Changde (Changteh) in the province of Hunan.
The purpose of the Japanese offensive was to maintain press ...
from 2 November 1943 – 20 December 1943. He was later involved in the capture of
Henyang and the
Battle of Changsha during
Operation Ichi-Go
Operation Ichi-Go () was a campaign of a series of major battles between the Imperial Japanese Army forces and the National Revolutionary Army of the Republic of China, fought from April to December 1944. It consisted of three separate battles in ...
in August 1944.
Yokoyama was reassigned back to mainland Japan as commander of both the
Western District Army and the
Japanese Sixteenth Area Army in November 1944. These were
home guard
Home guard is a title given to various military organizations at various times, with the implication of an emergency or reserve force raised for local defense.
The term "home guard" was first officially used in the American Civil War, starting ...
and
garrison
A garrison is any body of troops stationed in a particular location, originally to guard it. The term now often applies to certain facilities that constitute a military base or fortified military headquarters.
A garrison is usually in a city ...
organizations responsible for recruitment and
civil defense
Civil defense or civil protection is an effort to protect the citizens of a state (generally non-combatants) from human-made and natural disasters. It uses the principles of emergency management: Risk management, prevention, mitigation, prepara ...
, and were intended to oppose the projected
American invasion of western Japan. He was based in
Fukuoka
is the List of Japanese cities by population, sixth-largest city in Japan and the capital city of Fukuoka Prefecture, Japan. The city is built along the shores of Hakata Bay, and has been a center of international commerce since ancient times. ...
at the time of the
surrender of Japan
The surrender of the Empire of Japan in World War II was Hirohito surrender broadcast, announced by Emperor Hirohito on 15 August and formally Japanese Instrument of Surrender, signed on 2 September 1945, End of World War II in Asia, ending ...
.
In July 1946, Yokoyama was arrested by the
U.S. occupation authorities on suspicion of war crimes. In 1948, he was
sentenced to death
Capital punishment, also known as the death penalty and formerly called judicial homicide, is the state-sanctioned killing of a person as punishment for actual or supposed misconduct. The sentence ordering that an offender be punished in s ...
by a military commission for
Yokohama War Crimes Trials due to his direct
command responsibility
In the practice of international law, command responsibility (also superior responsibility) is the legal doctrine of hierarchical accountability for war crimes, whereby a commanding officer (military) and a superior officer (civil) are legally r ...
for
vivisection
Vivisection () is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as a pejorative catch-all term for Animal test ...
and other human medical experiments performed at the
Kyushu Imperial University on downed
Allied airmen. However, Yokoyama's sentence was later commuted to life in prison. He died in prison in 1952.
[, WAR CRIMES OFFICE Office of the Staff Judge Advocate Yokohama, Japan]
References
*
* Hayashi Saburo with Cox, Alvin D. 1959. Kogun: The Japanese Army in the Pacific War. Quantico, VA: The Marine Corps Association.
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External links
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Notes
{{DEFAULTSORT:Yokoyama, Isamu
1889 births
1952 deaths
Military personnel from Chiba Prefecture
Imperial Japanese Army generals of World War II
Japanese military attachés
Japanese prisoners sentenced to death
Japanese people who died in prison custody
People convicted in the Yokohama trials
Prisoners sentenced to death by the United States military
Prisoners who died in United States military detention