was a

lieutenant general Lieutenant general (Lt Gen, LTG and similar) is a three-star military rank (NATO code OF-8) used in many countries. The rank traces its origins to the Middle Ages, where the title of lieutenant general was held by the second-in-command on the ...

in the

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

Biography

Military career

Yasuoka was born in Sendai city, Kagoshima Prefecture (present day

Satsumasendai, Kagoshima is a Cities of Japan, city located in Kagoshima Prefecture, Japan. The modern city of Satsumasendai was established on October 12, 2004, from the merger of the city of Sendai, the towns of Hiwaki, Kagoshima, Hiwaki, Iriki, Kagoshima, Iriki, Ked� ...

) and was the son of an officer in the Imperial Japanese Army. After attending military preparatory schools in Kumamoto, he graduated from the 18th 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 1906. After attending the Army Toyama School, he graduated from the 26th class of the

Army Staff College Staff colleges (also command and staff colleges and War colleges) train military officers in the administrative, military staff and policy aspects of their profession. It is usual for such training to occur at several levels in a career. For exa ...

in 1914. After serving in a number of staff positions, he was assigned to the IJA 51st Infantry Regiment, rising to become its commander by 1922. He served n the staff of the

IJA 9th Division The was an infantry division in the Imperial Japanese Army. Its tsūshōgō code name was the or 1515 or 1573.Madez, ''Japanese Armed Forces Order of Battle, 1937-1945'', p. 35. The ''9th Division'' was one of six infantry divisions newly raise ...

, the IJA 29th Infantry Regiment and the IJA 16th Division and after his promotion to colonel in August 1930, as commander of the IJA 49th Infantry Regiment from 1930. In January 1935, he became Chief of Staff of the Hiroshima-based

IJA 5th Division The was an infantry division of the Imperial Japanese Army. Its call sign was the . The 5th Division was formed in Hiroshima in January 1871 as the , one of six regional commands created in the fledgling Imperial Japanese Army. Its personnel we ...

. Yasuoka was promoted to

major general Major general (abbreviated MG, maj. gen. and similar) is a military rank used in many countries. It is derived from the older rank of sergeant major general. The disappearance of the "sergeant" in the title explains the apparent confusion of ...

and given command of the IJA 30th Infantry Brigade in March 1935. He served as commandant of the Army Tank School from August 1936. In March 1938, he was promoted to

and was made commander of the IJA 1st Independent Mixed Brigade. With the start of the Soviet-Japanese Border Wars, Yasuoka's expertise in

armored warfare Armoured warfare or armored warfare (mechanized forces, armoured forces or armored forces) (American English; see spelling differences), is the use of armored fighting vehicles in modern warfare. It is a major component of modern methods of ...

was recognized when he was made commander of the

Yasuoka Detachment Yasuoka Detachment or Yasuoka Task Force, was an armored Japanese Imperial Army unit in 1939. It was commanded by Lt. General Yasuoka Masaomi, composed of 3rd Tank Regiment and 4th Tank Regiment (seventy-three tanks total), 64th Infantry Regim ...

, an armored task force of the

Kwantung Army ''Kantō-gun'' , image = Kwantung Army Headquarters.JPG , image_size = 300px , caption = Kwantung Army headquarters in Hsinking, Manchukuo , dates = April ...

, organized for the July 1939 offensive of the

Battle of Khalkhin Gol The Battles of Khalkhin Gol (russian: Бои на Халхин-Голе; mn, Халхын голын байлдаан) were the decisive engagements of the undeclared Soviet–Japanese border conflicts involving the Soviet Union, Mongolia, ...

. However, the Japanese army suffered a ruinous defeat at the hands of the combined Soviet-Mongolian forces and Yasuoka was relieved of command in July 1939 and his detachment was dissolved. He was placed in command of the reserve IJA Third Depot Division in August 1939, and went into the reserves in March 1941. He retired from the military at the end of the same month.

Governor of Surabaya

In July 1942, Yasuoka agreed to accept the post of governor of Surabaya in Japanese-occupied

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

, Netherlands East Indies. During his time in Surabaya, he learned enough of the

Javanese language Javanese (, , ; , Aksara Jawa: , Pegon: , IPA: ) is a Malayo-Polynesian language spoken by the Javanese people from the central and eastern parts of the island of Java, Indonesia. There are also pockets of Javanese speakers on the nort ...

to be able to make a speech in public, and was known for visiting school and government offices without notice. He attempted to employ as many native Indonesians in government positions as possible, both from a practical standpoint, but also from a belief that the Netherlands East Indies should be freed from colonial rule. He also released many of the Dutch officials who were held as prisoners of war to train the Indonesians to take their places. He held the post until the surrender of Japan in August 1945, whereupon he was arrested by Dutch colonial authorities and tried before a

military tribunal Military justice (also military law) is the legal system (bodies of law and procedure) that governs the conduct of the active-duty personnel of the armed forces of a country. In some nation-states, civil law and military law are distinct bod ...

where he was declared guilty of unspecified war crimes. He was condemned to death and hanged on 12 April 1948.

References

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External links

Footnotes

{{DEFAULTSORT:Yasuoka, Masaomi 1886 births 1948 deaths Military personnel from Kagoshima Prefecture Imperial Japanese Army generals of World War II Japanese generals Members of the Kwantung Army Japanese military personnel of World War II Japanese people convicted of war crimes Executed military personnel People executed by the Netherlands by hanging Japanese people executed abroad People executed for war crimes