The Imperial Japanese Armed Forces (IJAF, full or Nippon-gun () for short, meaning "Japanese Forces") were the unified forces of the

Empire of Japan The Empire of Japan, also known as the Japanese Empire or Imperial Japan, was the Japanese nation state that existed from the Meiji Restoration on January 3, 1868, until the Constitution of Japan took effect on May 3, 1947. From Japan–Kor ...

. Formed during the

Meiji Restoration The , referred to at the time as the , and also known as the Meiji Renovation, Revolution, Regeneration, Reform, or Renewal, was a political event that restored Imperial House of Japan, imperial rule to Japan in 1868 under Emperor Meiji. Althoug ...

in 1868,"One can date the 'restoration' of imperial rule from the edict of 3 January 1868." p. 334. they were disbanded in 1945, shortly after Japan's defeat to the

Allies of World War II The Allies, formally referred to as the United Nations from 1942, were an international Coalition#Military, military coalition formed during World War II (1939–1945) to oppose the Axis powers. Its principal members were the "Four Policeme ...

; the revised

Constitution of Japan The Constitution of Japan is the supreme law of Japan. Written primarily by American civilian officials during the occupation of Japan after World War II, it was adopted on 3 November 1946 and came into effect on 3 May 1947, succeeding the Meij ...

, drafted during the Allied occupation of Japan, replaced the IJAF with the present-day

Japan Self-Defense Forces The are the military forces of Japan. Established in 1954, the JSDF comprises the Japan Ground Self-Defense Force, the Japan Maritime Self-Defense Force, and the Japan Air Self-Defense Force. They are controlled by the Ministry of Defense ...

. 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 ...

and the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, Potsdam Declaration, when it was dissolved followin ...

functioned as the IJAF's primary service branches, with the country's aerial power being split between the

Army Air Service The United States Army Air Service (USAAS)Craven and Cate Vol. 1, p. 9 (also known as the ''"Air Service"'', ''"U.S. Air Service"'' and before its legislative establishment in 1920, the ''"Air Service, United States Army"'') was the aerial warf ...

under the former and the Navy Air Service under the latter.

History

The IJAF was founded with an edict emanated on 3 January 1868, as part of the Japanese reorganization of the army and the application of innovations during the

. The reorganization of the army and the navy during the Meiji period boosted Japanese military strength, allowing the Imperial Japanese Army and the Imperial Japanese Navy to achieve major victories, such as during the

First Sino-Japanese war The First Sino-Japanese War (25 July 189417 April 1895), or the First China–Japan War, was a conflict between the Qing dynasty of China and the Empire of Japan primarily over influence in Joseon, Korea. In Chinese it is commonly known as th ...

and the

Russo-Japanese War The Russo-Japanese War (8 February 1904 – 5 September 1905) was fought between the Russian Empire and the Empire of Japan over rival imperial ambitions in Manchuria and the Korean Empire. The major land battles of the war were fought on the ...

. The IJAF also served in WW1 and WW2. It was operational 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 ...

after

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

in 1945.

Organization

During the pre-war era the army and navy had separate school branches. Since the Meiji era, the Choshu Domain from

Yamaguchi Prefecture is a Prefectures of Japan, prefecture of Japan located in the Chūgoku region of Honshu. Yamaguchi Prefecture has a population of 1,377,631 (1 February 2018) and has a geographic area of 6,112 Square kilometre, km2 (2,359 Square mile, sq mi). ...

dominated the IJA. The IJN was dominated by the

Satsuma Domain The , briefly known as the , was a Han system, domain (''han'') of the Tokugawa shogunate of Japan during the Edo period from 1600 to 1871. The Satsuma Domain was based at Kagoshima Castle in Satsuma Province, the core of the modern city of ...

from

Kagoshima Prefecture is a Prefectures of Japan, prefecture of Japan located on the island of Kyushu and the Ryukyu Islands. Kagoshima Prefecture has a population of 1,527,019 (1 February 2025) and has a geographic area of 9,187 Square kilometre, km2 (3,547 Square m ...

. This resulted in that they operated separately rather than a single umbrella strategy. During the Showa period, the IJA and IJN had different outlooks on allies and enemies. The IJA considered

Nazi Germany Nazi Germany, officially known as the German Reich and later the Greater German Reich, was the German Reich, German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a Totalit ...

as a natural partner and the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

as a threat, while the IJN stressed that collaboration with

would hurt relations with the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

and the

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 ...

. Some equipment was also procured separately. For example, the IJA secured its own ships and self-designed submarines in World War 2. Former Prime Minister

Shigeru Yoshida was a Japanese diplomat and politician who served as prime minister of Japan from 1946 to 1947 and again from 1948 to 1954, serving through most of the country's occupation after World War II. Yoshida played a major role in determining the cour ...

criticized the sectionalism of the IJAF.

Interservice rivalry

The Imperial Army and Navy had a fierce interservice rivalry centering around how the Imperial Japanese Armed Forces ought to secure territories containing valuable natural resources not available at home to fuel and grow the Japanese economy. The Army mainly supported the

Hokushin-ron was a political doctrine of the Empire of Japan before World War II that stated that Manchuria and Siberia were Japan's sphere of interest and that the potential value to Japan for economic and territorial expansionism, expansion in those areas ...

doctrine, which called for expansion into Manchuria and Siberia and would have the army take on a prime role, while the Navy supported the

Nanshin-ron was a political doctrine in the Empire of Japan that stated that Southeast Asia and the Pacific Islands were Japan's sphere of interest and that their potential value to the Empire for economic and territorial expansion was greater than elsewh ...

doctrine, which stated that Japan ought to expand into

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

and the

Pacific Islands The Pacific islands are a group of islands in the Pacific Ocean. They are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of several ...

and would be reliant on the navy to do so.

Main chronology

Under Emperor Meiji

*1870 (1870) Proclamation of unified military system (Army is French-style, Navy is British-style) *1871 (1871) Goshinpei are organized by donations from Satsuma, Choshu, and Tosa. *Proclamation of conscription order in 1873 *1874 Saga Rebellion, Taiwan troop dispatch *Ganghwa Island Incident in 1875 *1876 Kumamoto Shinfuren Rebellion, Akizuki Rebellion, Hagi Rebellion *Meiji 10 (1877) Satsuma Rebellion *1882 (1882) Promulgation of the Imperial Rescript to Soldiers *1888 (1888) Promulgation of the Army General Staff Ordinance, the Navy General Staff Ordinance, and the Division Headquarters Ordinance *1889 (Meiji 22) Promulgation of the Constitution of the Empire of Japan *1893 (Meiji 26) Promulgation of the Wartime Imperial Headquarters Ordinance *Meiji 27 (1894) Sino-Japanese War *The Sino-Japanese War ended in 1895. Japanese troops requisition Taiwan based on the Treaty of Shimonoseki *1899 (Meiji 32) Boxer Rebellion Incident *1900 (Meiji 33) Established an active military officer system of the military minister, Kitasei incident *Meiji 37 (1904) Russo-Japanese War *1905 (Meiji 38) Operation Sakhalin, the end of the Russo-Japanese War

Under Emperor Taishō

*In 1913, the military minister can be appointed as a reserve, back-up, or retired general. *1914 Siemens scandal, World War I (Battle of Qingdao) *1918 Siberian intervention, end of World War I *1919 (Taisho 8) Promulgation of the Kwantung Army Headquarters Ordinance *Nikolayevsk Incident in 1920 *1921 Washington Naval Treaty *The Amakasu Incident in 1923 *Siberian intervention ended in 1925, Ugaki military contraction

Under Emperor Shōwa

*Shōwa 2 (1927) **First Shandong troops **First Nanking Incident *Shōwa 3 (1928) **Second Shandong troops **Jinan Incident **Zhang Zuolin bombing case *Shōwa 5 (1930) **London Naval Treaty **Taiwan Musha Incident *Shōwa 6 (1931) **March Incident **Manchurian Incident **October Incident *Shōwa 7 (1932) **January 28 Incident **May 15 Incident **Manchuria founded *Shōwa 9 (1934) **Washington Naval Treaty abolished *Shōwa 11 (1936) **February 26 Incident **Resurrection of the military minister's active military service system **Japan-Germany Anti-Comintern Pact *Shōwa 12 (1937) **China Incident (Sino-Japanese War) **Marco Polo Bridge Incident **Tongzhou case **Battle of Beiping-Tianjin **Battle of Shanghai **Rape of Nanking *Shōwa 13 (1938) **Battle of Wuhan **Battle of Lake Khasan **Promulgation of the National Mobilization Law *Shōwa 14 (1939) **The Battle of Khalkhin Gol *Shōwa 15 (1940) **Annexation of French Indochina *Shōwa 16 (1941) **Declaration of war against the United States and United Kingdom, Greater East Asia War (Pacific War), Southern Operation (Invasion of Hong Kong, Malayan Campaign, Pearl Harbor attack, etc.) **Sinking of HMS Prince of Wales and HMS Repulse *Shōwa 17 (1942) **Battle of Rabaul (start of New Guinea Campaign) **Fall of Singapore **Bombing of Darwin **Dutch East Indies Campaign **Battle of Yunnan-Burma Road **Battle of Ceylon **Battle of Midway **Kokoda Track Campaign *Shōwa 18 (1943) **Battle of Guadalcanal Island **Navy Instep Incident **Battle of Attu *Shōwa 19 (1944) **Navy B case **Operation C (U Go Offensive) **Operation Ichi-Go **Battle of Mariana and Palau Islands **Philippines Defense Battle **Creation of a special attack corps *Shōwa 20 (1945) **February Yalta Conference **Rape of Manila **Battle of Iwo Jima **March Tokyo air raid **Battle of Okinawa **Participation in the Soviet Union against Japan (Soviet invasion of Manchuria / Battle of Sakhalin / Battle of Shumshu) **Accepting the Potsdam Declaration **Soviet troops occupy the South Karafuto and Kuril Islands **September 2-Japanese Instrument of Surrender Signing Ceremony on Battleship Missouri (Japanese Instrument of Surrender, All Armies Stopped Combat, Disarmament Order), Greater East Asia War (Pacific War) and End of World War II **Soviet Union occupies the Northern Territories **November The Ministry of the Army and the Ministry of the Navy are dismantled and become the 1st Ministry of Demobilization and the 2nd Ministry of Demobilization. *Shōwa 21 (1946) **May International Military Tribunal for the Far East opens **November 3-Promulgation of the Constitution of Japan *Shōwa 22 (1947) **May 3-Enforcement of the Constitution of Japan *Shōwa 25 (1950) **August 10-Establishment of National Police Reserve *Shōwa 27 (1952) **August 10-National Safety Forces reorganization *Shōwa 29 (1954) **July 1-Established "Self-Defense Forces (land, sea, aviation)" and established the Defense Agency (shifted to "Ministry of Defense" on January 9, 2007)

Components

* Supreme War Council **

Imperial General Headquarters The was part of the Supreme War Council (Japan), Supreme War Council and was established in 1893 to coordinate efforts between the Imperial Japanese Army and Imperial Japanese Navy during wartime. In terms of function, it was approximately equi ...

** Supreme Commander-in-Chief of the Imperial Japanese Army and Navy *

** Marshal-General of the Imperial Japanese Army ** Imperial Japanese Army General Staff **

Imperial Japanese Army Air Service The Imperial Japanese Army Air Service (IJAAS) or Imperial Japanese Army Air Force (IJAAF; ) was the Military aviation, aviation force of the Imperial Japanese Army (IJA). Its primary mission was to provide tactical close air support for ground ...

*** Imperial Japanese Army Airborne Forces ** Imperial Japanese Army Military Police **

Imperial Guard of Japan The Imperial Guard of Japan has been two separate organizations dedicated to the protection of the Emperor of Japan and the Imperial Family, palaces and other imperial properties. The first was the , a quasi-independent elite branch of the Imperial ...

** Marshal-Admiral of the Imperial Japanese Navy **

Imperial Japanese Navy General Staff The was the highest organ within the Imperial Japanese Navy (IJN). In charge of planning and operations, it was headed by an Admiral headquartered in Tokyo. History Created in 1893, the Navy General Staff took over operational (as opposed to a ...

Imperial Japanese Navy Air Service The (IJNAS) was the air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War. The Japanese military acquired its first aircraft in ...

** Imperial Japanese Navy Land Forces *** Special Naval Landing Forces *** Imperial Japanese Navy Marine Corps ** Imperial Japanese Navy Military Police

Citations

Bibliography

* {{Authority control Military of the Empire of Japan

History

Organization

Interservice rivalry

Main chronology

Under Emperor Meiji

Under Emperor Taishō

Under Emperor Shōwa

Components

See also

Citations

Bibliography