The was an

infantry division A division is a large military unit or Formation (military), formation, usually consisting of between 10,000 and 25,000 soldiers. In most armies, a division is composed of several regiments or brigades; in turn, several divisions typically mak ...

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 ...

. Its

tsūshōgō were unit code names used by the Imperial Japanese Army (IJA) during World War II. Each ''tsūshōgō'' consisted of a and a . Unit Character Codes typically consisted of one character, although some units established in the late stages of the ...

code name A code name, codename, call sign, or cryptonym is a code word or name used, sometimes clandestinely, to refer to another name, word, project, or person. Code names are often used for military purposes, or in espionage. They may also be used in ...

was the . The 21st Division was created on 4 April 1938 as a

triangular division A triangular division is a designation given to the way military divisions are organized. In a triangular organization, the division's main body is composed of three regimental maneuver elements. These regiments may be controlled by a brigade hea ...

as part of the military buildup following the outbreak of 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 ...

, along with the resurrected 17th and 18th Divisions, and the new 22nd and 23rd Divisions. Its original headquarters was in a suburb of the city of

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 ...

, and its troops were recruited primarily from communities in Ishikawa and

Toyama Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. Toyama Prefecture has a population of 993,848 (1 January 2025) and has a geographic area of 4,247.61 km2 (1,640.01 sq mi). Toyama Prefecture borders Ishikawa Prefecture to the ...

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Initially assigned to the

Japanese Northern China Area Army The was an area army of the Imperial Japanese Army during the Second Sino-Japanese War. History The Japanese North China Area Army was formed on August 21, 1937 under the control of the Imperial General Headquarters. It was transferred to th ...

, it was deployed to the Chinese mainland from 15 July 1938, serving as a garrison force in

Xuzhou Xuzhou ( zh, s=徐州), also known as Pengcheng () in ancient times, is a major city in northwestern Jiangsu province, China. The city, with a recorded population of 9,083,790 at the 2020 Chinese census, 2020 census (3,135,660 of which lived in ...

. In February 1939, it participated in fighting in the Kahoku district of

Hebei Hebei is a Provinces of China, province in North China. It is China's List of Chinese administrative divisions by population, sixth-most populous province, with a population of over 75 million people. Shijiazhuang is the capital city. It bor ...

province. Under the command of Lieutenant Commander

Hisakazu Tanaka was a lieutenant general in the Imperial Japanese Army, and governor of Japanese-occupied Hong Kong in World War II. His given name is occasionally transliterated "Hisaichi". Biography Early career Tanaka was born in Hyōgo Prefecture to the K ...

from 1940 to 1943 as part of the Japanese 12th Army, the division participated in counter-insurgency operations in Northern China as well as the

Battle of South Shanxi The Battle of South Shanxi , also known as the Battle of Jinnan () and Zhongtiao Mountains campaign () by the Chinese and as the Chungyuan Operation by the Japanese, was one of the 22 major engagements between the National Revolutionary Army a ...

in May 1941, and the subsequent

Hundred Regiments Offensive The Hundred Regiments Offensive or the Hundred Regiments Campaign () (20 August – 5 December 1940) was a major campaign of the Chinese Communist Party's National Revolutionary Army divisions. It was commanded by Peng Dehuai against the Imp ...

. From November 1941, the division was transferred to the control of the

Southern Expeditionary Army Group The was a general army of the Imperial Japanese Army during World War II. It was responsible for all military operations in South East Asian and South West Pacific campaigns of World War II. Its military symbol was NA. The Southern Expediti ...

and transferred to the Philippines, landing at

Lingayen Gulf Lingayen Gulf is a large gulf on northwestern Luzon in the Philippines, stretching . It is framed by the provinces of Pangasinan and La Union and sits between the Zambales Mountains and the Cordillera Central (Luzon), Cordillera Central. The Agno ...

on 26 February 1942. After the completion of the Philippines Campaign, from December 1943, the division was sent to

French Indochina French Indochina (previously spelled as French Indo-China), officially known as the Indochinese Union and after 1941 as the Indochinese Federation, was a group of French dependent territories in Southeast Asia from 1887 to 1954. It was initial ...

under the control of the IJA 38th Army, Assigned to a garrison role in

Hanoi Hanoi ( ; ; ) is the Capital city, capital and List of cities in Vietnam, second-most populous city of Vietnam. The name "Hanoi" translates to "inside the river" (Hanoi is bordered by the Red River (Asia), Red and Black River (Asia), Black Riv ...

, it remained in Indochina through the end of the

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 ...

except for a brief period in late 1944 when it crossed back into China to participate in

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 ...

. The division played a critical role in the

Japanese coup d'état in French Indochina The Japanese coup d'état in French Indochina, known as , was a Empire of Japan, Japanese operation that took place on 9 March 1945, towards the end of World War II. With Japanese forces losing the war and the threat of an Allies of World War I ...

of March 1945, which resulted in the proclamation of the

Empire of Vietnam The Empire of Vietnam (; Literary Chinese and Japanese language, Contemporary Japanese: ; Japanese language, Modern Japanese: ) was a short-lived Japanese puppet state, puppet state of Empire of Japan, Imperial Japan between March 11 and Abdicat ...

independent from French rule. It remained as a garrison force in Hanoi until 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 August 1945. A number of its troops refused to return to Japan and defected to join the

Viet Minh The Việt Minh (, ) is the common and abbreviated name of the League for Independence of Vietnam ( or , ; ), which was a Communist Party of Vietnam, communist-led national independence coalition formed at Pác Bó by Hồ Chí Minh on 19 May 1 ...

in their struggle for independence (

First Indochina War The First Indochina War (generally known as the Indochina War in France, and as the Anti-French Resistance War in Vietnam, and alternatively internationally as the French-Indochina War) was fought between French Fourth Republic, France and Việ ...

) against the returning French colonial forces. But in 1954 they were ordered to return to Japan by the Vietnamese government.

References

* * * * Madej, W. Victor. ''Japanese Armed Forces Order of Battle, 1937-1945'' volsAllentown, PA: 1981 * This article incorporates material from the Japanese Wikipedia page 第21師団 (日本軍), accessed 7 March 2016 {{DEFAULTSORT:21st Division (Imperial Japanese Army) Japanese World War II divisions Infantry divisions of Japan Military units and formations established in 1938 Military units and formations disestablished in 1945 Military history of Vietnam during World War II 1938 establishments in Japan 1945 disestablishments in Japan

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See also

References