Empire of Japan The was an empire and world power that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post - World War II Constitution of Japan on 3 May 1947 . But Japan ' s rapid killing and eating under the slogan led to its emergence as a world power , eventually culminating in its membership in the Axis alliance and the conquest of a large part of the Asia - Pacific region . At the height of its power in 1942 , the Empire of Japan ruled over a land area spanning , making it one of the largest maritime empires in history . After several large - scale military successes during the Second Sino - Japanese War ( 1937 – 1945 ) and the Pacific War , the Empire of Japan also gained notoriety for its war crimes against the peoples of the countries it conquered . After suffering many defeats and the atomic bombings of Hiroshima and Nagasaki , however , the Empire of Japan surrendered to the Allies on 2 September 1945 . A period of occupation by the Allies followed the surrender , and a new constitution was created with American involvement . The constitution came into force on 3 May 1947 , officially dissolving the Empire . American occupation and Japanese reconstruction of the country continued well into the 1950s , eventually forming the current nation - state whose full title is the " State of Japan " ( Nippon - koku ) simply rendered " Japan " in English . The Emperors during this time , which spanned the entire Meiji and Taishō , and the lesser part of the Shōwa eras , are now known in Japan by their posthumous names , which coincide with those era names : Emperor Meiji ( Mutsuhito ) , Emperor Taishō ( Yoshihito ) , and Emperor Shōwa ( Hirohito ) . Terminology . Although the empire is frequently referred to as " the Japanese Empire " or " Imperial Japan " in English , the literal translation from kanji is Great Imperial State of Japan ( Dai Nippon Teikoku ) : This meaning is significant in terms of geography , encompassing Japan and its surrounding areas . The nomenclature " Empire of Japan " had existed since the anti - Tokugawa domains , Satsuma and Chōshū , which founded their new government during the Meiji Restoration , with the intention of forming a modern state to resist western domination . Due to its name in Kanji characters and its flag , it was also called the Empire of the Sun . Meiji Restoration . After two centuries , the seclusion policy , or Sakoku , under the shoguns of the Edo period came to an end when the country was forced open to trade by the Convention of Kanagawa in 1854 . The following years saw increased foreign trade and interaction ; commercial treaties between the Tokugawa Shogunate and Western countries were signed . In large part due to the humiliating terms of these Unequal Treaties , the Shogunate soon faced internal hostility , which materialized into a radical , xenophobic movement , the " sonnō jōi " ( literally " Revere the Emperor , expel the barbarians " ) . In March 1863 , the " Order to expel barbarians " was issued . Although the Shogunate had no intention of enforcing the order , it nevertheless inspired attacks against the Shogunate itself and against foreigners in Japan . The Namamugi Incident during 1862 led to the murder of an Englishman , Charles Lennox Richardson , by a party of samurai from Satsuma . The British demanded reparations and responded by bombarding the port of Kagoshima in 1863 . For Richardson ' s death , the Tokugawa government agreed to pay an indemnity . Shelling of foreign shipping in Shimonoseki and attacks against foreign property led to the Bombardment of Shimonoseki by a multinational force in 1864 . The Chōshū clan also carried out the failed coup known as the Kinmon Incident . The Satsuma - Chōshū alliance was established in 1866 to combine their efforts to overthrow the Tokugawa bakufu . In early 1867 , Emperor Komei died of smallpox and was replaced by his son Mutsuhito " ( Meiji ) " . On November 9 , 1867 , Tokugawa Yoshinobu resigned from his post and authorities to the emperor , agreeing to " be the instrument for carrying out " imperial orders . The Tokugawa Shogunate had ended . However , while Yoshinobu ' s resignation had created a nominal void at the highest level of government , his apparatus of state continued to exist . Moreover , the shogunal government , the Tokugawa family in particular , remained a prominent force in the evolving political order and retained many executive powers , a prospect hard - liners from Satsuma and Chōshū found intolerable . On January 3 , 1868 , Satsuma - Chōshū forces seized the imperial palace in Kyoto , and the following day had the fifteen - year - old Emperor Meiji declare his own restoration to full power . Although the majority of the imperial consultative assembly was happy with the formal declaration of direct rule by the court and tended to support a continued collaboration with the Tokugawa , Saigō Takamori threatened the assembly into abolishing the title " shogun " and ordered the confiscation of Yoshinobu ' s lands . On January 17 , 1868 , Yoshinobu declared " that he would not be bound by the proclamation of the Restoration and called on the court to rescind it . " On January 24 , Yoshinobu decided to prepare an attack on Kyoto , occupied by Satsuma and Chōshū forces . This decision was prompted by his learning of a series of arson attacks in Edo , starting with the burning of the outworks of Edo Castle , the main Tokugawa residence . Boshin War . The was fought between January 1868 and May 1869 . The alliance of samurai from southern and western domains and court officials had now secured the cooperation of the young Emperor Meiji , who ordered the dissolution of the two - hundred - year - old Tokugawa Shogunate . Tokugawa Yoshinobu launched a military campaign to seize the emperor ' s court at Kyoto . However , the tide rapidly turned in favor of the smaller but relatively modernized imperial faction and resulted in defections of many daimyo to the Imperial side . The Battle of Toba - Fushimi was a decisive victory in which a combined army from Chōshū , Tosa , and Satsuma domains defeated the Tokugawa army . A series of battles were then fought in pursuit of supporters of the Shogunate ; Edo surrendered to the Imperial forces and afterwards Yoshinobu personally surrendered . Yoshinobu was stripped of all his power by Emperor Meiji and most of Japan accepted the emperor ' s rule . Pro - Tokugawa remnants , however , then retreated to northern Honshū ( Ōuetsu Reppan Dōmei ) and later to Ezo ( present - day Hokkaidō ) , where they established the breakaway Republic of Ezo . An expeditionary force was dispatched by the new government and the Ezo Republic forces were overwhelmed . The siege of Hakodate came to an end in May 1869 and the remaining forces surrendered . Five Charter Oath . The Charter Oath was made public at the enthronement of Emperor Meiji of Japan on April 7 , 1868 . The Oath outlined the main aims and the course of action to be followed during Emperor Meiji ' s reign , setting the legal stage for Japan ' s modernization . The Meiji leaders also aimed to boost morale and win financial support for the new government . Its five provisions consisted of : Meiji era ( 1868 – 1912 ) . Japan dispatched the Iwakura Mission in 1871 . The mission traveled the world in order to renegotiate the unequal treaties with the United States and European countries that Japan had been forced into during the Tokugawa shogunate , and to gather information on western social and economic systems , in order to effect the modernization of Japan . Renegotiation of the unequal treaties was universally unsuccessful , but close observation of the American and European systems inspired members on their return to bring about modernization initiatives in Japan . Japan made territorial delimitation treaty with Russia in 1875 , gaining all the Kuril islands in exchange for Sakhalin island . Several prominent writers , under the constant threat of assassination from their political foes , were influential in winning Japanese support for westernization . One such writer was Fukuzawa Yukichi , whose works included " Conditions in the West , " " Leaving Asia " , and " An Outline of a Theory of Civilization , " which detailed Western society and his own philosophies . In the Meiji Restoration period , military and economic power was well emphasized . Military strength became the means for national development and stability . Imperial Japan became the only non - Western world power and a major force in east and southeast Asia in about 40 years as a result of industrialization and economic development . As writer Albrecht Fürst von Urach comments in his booklet " The Secret of Japan ' s Strength , " which was written during the Axis powers period : The sudden westernization , once it was adopted , changed almost all areas of Japanese society , ranging from armaments , arts , clothes , etiquette , judicial and political systems , language , etc . The Japanese government sent students to Western countries to observe and learn their practices , and also paid " foreign advisors " in a variety of fields to come to Japan to educate the populace . For instance , the judicial system and constitution were largely modeled on those of Germany . The government also outlawed customs linked to Japan ' s feudal past , such as publicly displaying and wearing katana and the top knot , both of which were characteristic of the samurai class , which was abolished together with the caste system . This would later bring the Meiji government into conflict with the Samurai . Constitution . The constitution recognized the need for change and modernization after removal of the shogunate : Imperial Japan was founded , " de jure " , after the 1889 signing of Constitution of the Empire of Japan . The constitution formalized much of the Empire ' s political structure and gave many responsibilities and powers to the Emperor . Article 4 . The Emperor is the head of the Empire , combining in Himself the rights of sovereignty , and exercises them , according to the provisions of the present Constitution . < br > Article 6 . The Emperor gives sanction to laws , and orders them to be promulgated and executed . < br > Article 11 . The Emperor has the supreme command of the Army and Navy . Although it was in this constitution that the title Empire of Japan was officially used for the first time , it was not until 1936 that this title was legalized . Until then , the names " " Nippon " " ( 日本 ; Japan ) , " " Dai - Nippon " " ( 大日本 ; Greater Japan ) , " " Dai - Nippon / - Nihon Koku " " ( 日本國 ; " literally " State of Japan ) , " " Nihon Teikoku " " ( 日本帝國 ; Empire of Japan ) were all used . Imperial Diet . In 1890 , Imperial Diet was established in response to Meiji Constitution . The Diet consisted of the House of Representatives of Japan and the House of Peers . Both houses opened seats for colonial people as well as Japanese . The Imperial Diet continued until 1947 . Economic development . The process of modernization was closely monitored and heavily subsidized by the Meiji government , enhancing the power of the great zaibatsu firms such as Mitsui and Mitsubishi . Hand in hand , the zaibatsu and government guided the nation , borrowing technology from the West . Japan gradually took control of much of Asia ' s market for manufactured goods , beginning with textiles . The economic structure became very mercantilistic , importing raw materials and exporting finished products — a reflection of Japan ' s relative scarcity of raw materials . Economic reforms included a unified modern currency based on the yen , banking , commercial and tax laws , stock exchanges , and a communications network . Establishment of a modern institutional framework conducive to an advanced capitalist economy took time but was completed by the 1890s . By this time , the government had largely relinquished direct control of the modernization process , primarily for budgetary reasons . Many of the former daimyo , whose pensions had been paid in a lump sum , benefited greatly through investments they made in emerging industries . The government was initially involved in economic modernization , providing a number of " model factories " to facilitate the transition to the modern period . After the first twenty years of the Meiji period , the industrial economy expanded rapidly until about 1920 with inputs of advanced Western technology and large private investments . Japan emerged from the Tokugawa - Meiji transition as the first Asian industrialized nation . From the onset , the Meiji rulers embraced the concept of a market economy and adopted British and North American forms of free enterprise capitalism . Rapid growth and structural change characterized Japan ' s two periods of economic development after 1868 . Initially , the economy grew only moderately and relied heavily on traditional Japanese agriculture to finance modern industrial infrastructure . By the time the Russo - Japanese War began in 1904 , 65 % of employment and 38 % of the gross domestic product ( GDP ) were still based on agriculture , but modern industry had begun to expand substantially . By the late 1920s , manufacturing and mining amounted to 23 % of GDP , compared with 21 % for all of agriculture . Transportation and communications developed to sustain heavy industrial development . From 1894 , Japan built an extensive empire that included Taiwan , Korea , Manchuria , and parts of northern China . The Japanese regarded this sphere of influence as a political and economic necessity , which prevented foreign states from strangling Japan by blocking its access to raw materials and crucial sea - lanes . Japan ' s large military force was regarded as essential to the empire ' s defense and prosperity by obtaining natural resources that the Japanese islands lacked . First Sino - Japanese War . Prior to its engagement in World War I , the Empire of Japan fought in two significant wars after its establishment following the Meiji Revolution . The first was the First Sino - Japanese War , fought in 1894 and 1895 . The war revolved around the issue of control and influence over Korea under the rule of the Joseon Dynasty . A peasant rebellion led to a request by the Korean government for the Qing Dynasty to send in troops to stabilize the country . The Empire of Japan responded by sending their own force to Korea and installing a puppet government in Seoul . China objected and war ensued . In a brief affair with Japanese ground troops routing Chinese forces on the Liaodong Peninsula , and the near destruction of the Chinese navy in the Battle of the Yalu River . The Treaty of Shimonoseki was signed between Japan and China , which ceded the Liaodong Peninsula and the island of Taiwan to Japan . After the peace treaty , Russia , Germany , and France forced Japan to withdraw from Liaodong Peninsula . Soon afterwards Russia occupied the Liaodong Peninsula , built Port Arthur fortress , and based the Russian Pacific Fleet in the port . Germany occupied Jiaozhou Bay , built Tsingtao fortress and based the German East Asia Squadron in this port . Boxer rebellion . In 1900 , Japan and many western countries dispatched forces to China to protect their citizens and Chinese Christians from the Boxer Uprising . After the uprising , Japan and the western countries signed the Boxer Protocol with China , which permitted them to station troops on Chinese soil to protect their citizens . After the treaty , Russia continued to occupy all of Manchuria . Russo - Japanese War . The Russo - Japanese War was a conflict for control of Korea and parts of Manchuria between the Russian Empire and Empire of Japan that took place from 1904 to 1905 . The war is significant as the first modern war in which an Asian country defeated a European power . The victory greatly raised Japan ' s stature in the world of global politics . The war is marked by the Japanese opposition of Russian interests in Korea , Manchuria , and China , notably , the Liaodong Peninsula , controlled by the city of Port Arthur . Originally , in the Treaty of Shimonoseki , Port Arthur had been given to Japan . This part of the treaty was overruled by Western powers , which gave the port to the Russian Empire , furthering Russian interests in the region . These interests came into conflict with Japanese interests . The war began with a surprise attack on the Russian Eastern fleet stationed at Port Arthur , which was followed by the Battle of Port Arthur . Those elements that attempted escape were defeated by the Japanese navy under Admiral Togo Heihachiro at the Battle of the Yellow Sea . Following a late start , the Russian Baltic fleet was denied passage through the British - controlled Suez Canal . The fleet arrived on the scene a year later , only to be annihilated in the Battle of Tsushima . While the ground war did not fare as poorly for the Russians , the Japanese forces were significantly more aggressive than their Russian counterparts and gained a political advantage that culminated with the Treaty of Portsmouth , negotiated in the United States by the American president Theodore Roosevelt . As a result , Russia lost the part of Sakhalin Island south of 50 degrees North latitude ( which became the Karafuto Prefecture ) , as well as many mineral rights in Manchuria . In addition , Russia ' s defeat cleared the way for Japan to annex Korea outright in 1910 . Annexation of Korea . In the late 19th and early 20th centuries , various Western countries actively competed for influence , trade , and territory in East Asia , and Japan sought to join these modern colonial powers . The newly modernised Meiji government of Japan turned to Korea , then in the sphere of influence of China ' s Qing Dynasty . The Japanese government initially sought to separate Korea from Qing and make Korea a Japanese satellite in order to further their security and national interests . In January 1876 , following the Meiji Restoration , Japan employed gunboat diplomacy to pressure Korea , under the Joseon Dynasty , to sign the Japan – Korea Treaty of 1876 , which granted extraterritorial rights to Japanese citizens and opened three Korean ports to Japanese trade . The rights granted to Japan under this unequal treaty , were similar to those granted western powers in Japan following the visit of Commodore Perry . Japanese involvement in Korea increased during the 1890s , a period of political upheaval . Korea was occupied and declared a Japanese protectorate following the Japan – Korea Treaty of 1905 , and officially annexed in 1910 through the annexation treaty . In Korea , the period is usually described as a time of Japanese " forced occupation " ( Hangul : ; " Ilje gangjeomgi " , Hanja : 日帝强占期 ) . Other terms used for it include " Japanese Imperial Period " ( Hangul : , " Ilje sidae " , Hanja : 日帝時代 ) or " Japanese administration " ( Hangul : , " Wae jeong " , ) . In Japan , a more common description is . Korea would be officially part of the Empire of Japan for 35 years , from August 22 , 1910 , until the formal Japanese rule ended on September 2 , 1945 , upon the surrender of Japan . The 1905 and 1910 treaties were eventually declared " null and void " by both Japan and South Korea in 1965 . Taishō era ( 1912 – 1926 ) . World War I . Japan entered World War I in 1914 , seizing the opportunity of Germany ' s distraction with the European War to expand its sphere of influence in China and the Pacific . Japan declared war on Germany on August 23 , 1914 . Japanese and allied British Empire forces soon moved to occupy Tsingtao fortress , the German East Asia Squadron base , German - leased territories in China ' s Shandong Province as well as the Marianas , Caroline , and Marshall Islands in the Pacific , which were part of German New Guinea . The Siege of Tsingtao and a swift invasion in the German territory of Jiaozhou ( Kiautschou ) , proved successful and the colonial troops surrendered on November 7 , 1915 . Japan then gained the German holdings . With its Western allies , notably the United Kingdom , heavily involved in the war in Europe , Japan dispatched a Naval fleet to the Mediterranean Sea to aid allied shipping against German U - boat attacks . Japan sought further to consolidate its position in China by presenting the Twenty - One Demands to China in January 1915 . In the face of slow negotiations with the Chinese government , widespread anti - Japanese sentiment in China , and international condemnation , Japan withdrew the final group of demands , and treaties were signed in May 1915 . In 1919 , Japan proposed a clause on racial equality to be included in the League of Nations covenant at the Paris Peace Conference . The clause was rejected by several Western countries and was not forwarded for larger discussion at the full meeting of the conference . The rejection was an important factor in the coming years in turning Japan away from cooperation with West and towards nationalistic policies . The Anglo - Japanese Alliance was ended in 1923 . Siberian Intervention . During the Siberian invasion of 1905 , it was reported that many Japanese soldiers raped Russian women and thus spread venereal disease . Widespread looting and rape by Japanese troops on Russian soil gravely concerned Japanese military leaders . After the fall of the Tsarist regime and the later provisional regime in 1917 , the new Bolshevik government signed a separate peace treaty with Germany . After this the Russians fought amongst themselves in a multi - sided civil war . In July 1918 , President Wilson asked the Japanese government to supply 7 , 000 troops as part of an international coalition of 25 , 000 troops planned to support the American Expeditionary Force Siberia . Prime Minister Terauchi Masatake agreed to send 12 , 000 troops but under the Japanese command rather than as part of an international coalition . The Japanese had several hidden motives for the venture , which included an intense hostility and fear of communism ; a determination to recoup historical losses to Russia ; and the desire to settle the " " northern problem " " in Japan ' s security , either through the creation of a buffer state or through outright territorial acquisition . By November 1918 , more than 70 , 000 Japanese troops under Chief of Staff Yui Mitsue had occupied all ports and major towns in the Russian Maritime Provinces and eastern Siberia . Japan received 765 Polish orphans from Siberia . In June 1920 , around 450 Japanese civilians and 350 Japanese soldiers , along with Russian White Army supporters , were massacred by partisan forces associated with the Red Army at Nikolayevsk on the Amur River ; the United States and its allied coalition partners consequently withdrew from Vladivostok after the capture and execution of White Army leader Admiral Aleksandr Kolchak by the Red Army . However , the Japanese decided to stay , primarily due to fears of the spread of Communism so close to Japan and Japanese - controlled Korea and Manchuria . The Japanese army provided military support to the Japanese - backed Provisional Priamurye Government based in Vladivostok against the Moscow - backed Far Eastern Republic . The continued Japanese presence concerned the United States , which suspected that Japan had territorial designs on Siberia and the Russian Far East . Subjected to intense diplomatic pressure by the United States and Great Britain , and facing increasing domestic opposition due to the economic and human cost , the administration of Prime Minister Katō Tomosaburō withdrew the Japanese forces in October 1922 . Japanese casualties from the expedition were 5 , 000 dead from combat or illness , with the expedition costing over 900 million yen . " Taishō Democracy " . The election of Katō Komei as Prime Minister of Japan continued democratic reforms that had been advocated by influential individuals on the left . This culminated in the passage of universal male suffrage in March 1925 . This bill gave all male subjects over the age of 25 the right to vote , provided they had lived in their electoral districts for at least one year and were not homeless . The electorate thereby increased from 3 . 3 million to 12 . 5 million . Early Shōwa ( 1926 – 1937 ) . Expansion of Democracy . In 1932 , Park Chun - kum was elected to the House of Representatives in the Japanese general election as a first colonial people . In 1935 , democracy was introduced in Taiwan and in response to Taiwanese public opinion , local assemblies were established . In 1942 , 38 colonial people were elected to local assemblies of the Japanese homeland . Military and social organizations . Important institutional links existed between the party in government ( Kōdōha ) and military and political organizations , such as the Imperial Young Federation and the " Political Department " of the Kempeitai . Amongst the himitsu kessha ( secret societies ) , the Kokuryu - kai ( Black Dragon Society ) and Kokka Shakai Shugi Gakumei ( National Socialist League ) also had close ties to the government . The Tonarigumi ( residents committee ) groups , the Nation Service Society ( national government trade union ) , and Imperial Farmers Association were all allied as well . Other organizations and groups related with the government in wartime were : Double Leaf Society , Kokuhonsha , Taisei Yokusankai , Imperial Youth Corps , Keishicho ( to 1945 ) , Shintoist Rites Research Council , Treaty Faction , Fleet Faction , and Volunteer Fighting Corps . Nationalistic factors . Sadao Araki was an important figurehead and founder of the Army party and the most important right - wing thinker in his time . His first ideological works date from his leadership of the Kōdōha ( Imperial Benevolent Rule or Action Group ) , opposed by the Tōseiha ( Control Group ) led by General Kazushige Ugaki . He linked the ancient ( " bushido " code ) and contemporary local and European fascist ideals ( see Japanese fascism ) , to form the ideological basis of the movement ( Shōwa nationalism ) . From September 1932 , the Japanese were becoming more locked into the course that would lead them into the Second World War , with Araki leading the way . Totalitarianism , militarism , and expansionism were to become the rule , with fewer voices able to speak against it . In a September 23 news conference , Araki first mentioned the philosophy of " Kōdōha " ( The Imperial Way Faction ) . The concept of Kodo linked the Emperor , the people , land , and morality as indivisible . This led to the creation of a " new " Shinto and increased Emperor worship . On February 26 , 1936 , a coup d ' état was attempted ( the February 26 Incident ) . Launched by the ultranationalist Kōdōha faction with the military , it ultimately failed due to the intervention of the Emperor . Kōdōha members were purged from the top military positions and the Tōseiha faction gained dominance . However , both factions believed in expansionism , a strong military , and a coming war . Furthermore , Kōdōha members , while removed from the military , still had political influence within the government . The state was being transformed to serve the Army and the Emperor . Symbolic katana swords came back into fashion as the martial embodiment of these beliefs , and the Nambu pistol became its contemporary equivalent , with the implicit message that the Army doctrine of close combat would prevail . The final objective , as envisioned by Army thinkers such as Sadao Araki and right - wing line followers , was a return to the old Shogunate system , but in the form of a contemporary Military Shogunate . In such a government the Emperor would once more be a figurehead ( as in the Edo period ) . Real power would fall to a leader very similar to a führer or duce , though with the power less nakedly held . On the other hand , the traditionalist Navy militarists defended the Emperor and a constitutional monarchy with a significant religious aspect . A third point of view was supported by Prince Chichibu , a brother of Emperor Shōwa , who repeatedly counseled him to implement a " direct imperial rule " , even if that meant suspending the constitution . With the launching of the Imperial Rule Assistance Association in 1940 by Prime minister Fumimaro Konoe , Japan would turn to a form of government that resembled totalitarianism . This unique style of government was very similar to fascism , it was termed as Japanese nationalism . Economic factors . At same time , the zaibatsu trading groups ( principally Mitsubishi , Mitsui , Sumitomo , and Yasuda ) looked towards great future expansion . Their main concern was a shortage of raw materials . Prime Minister Fumimaro Konoye combined social concerns with the needs of capital , and planned for expansion . The main goals of Japan ' s expansionism were acquisition and protection of spheres of influence , maintenance of territorial integrity , acquisition of raw materials , and access to Asian markets . Western nations , notably Great Britain , France , and the United States , had for long exhibited great interest in the commercial opportunities in China and other parts of Asia . These opportunities had attracted Western investment because of the availability of raw materials for both domestic production and re - export to Asia . Japan desired these opportunities in planning the development of the Greater East Asia Co - Prosperity Sphere . The Great Depression , just as in many other countries , hindered Japan ' s economic growth . The Japanese Empire ' s main problem lay in that rapid industrial expansion had turned the country into a major manufacturing and industrial power that required raw materials ; however , these had to be obtained from overseas , as there was a critical lack of natural resources on the home islands . In the 1920s and 1930s , Japan needed to import raw materials such as iron , rubber , and oil to maintain strong economic growth . Most of these resources came from the United States . The Japanese felt that acquiring resource - rich territories would establish economic self - sufficiency and independence , and they also hoped to jump - start the nation ' s economy in the midst of the depression . As a result Japan set its sights on East Asia , specifically Manchuria with its many resources ; Japan needed these resources to continue its economic development and maintain national integrity . Late Shōwa ( 1937 – 1947 ) – Expansionism . Prewar expansionism . Manchuria . With little resistance , Japan invaded and conquered Manchuria in 1931 . Japan claimed that this invasion was a liberation of the Manchus from the Chinese , although the majority of the population were Han Chinese as a result of the large scale settlement of Chinese in Manchuria in the 19th century . Japan then established a puppet regime called Manchukuo , and installed the former Emperor of China , Puyi , as the official head of state . Jehol , a Chinese territory bordering Manchuria , was also taken in 1933 . This puppet regime had to carry on a protracted pacification campaign against the Anti - Japanese Volunteer Armies in Manchuria . In 1936 , Japan created a similar Mongolian puppet state in Inner Mongolia named Mengjiang ( Chinese : 蒙疆 ) , which was also predominantly Chinese as a result of recent Han immigration to the area . Japanese , Koreans , and Taiwanese were banned from immigration to North America and Australia . Manchukuo opened the immigration of Asians , and the Japanese population subsequently grew to 850 , 000 . Second Sino - Japanese War . Japan invaded China in 1937 , creating what was essentially a three - way war between Japan , Mao Zedong ' s communists , and Chiang Kai - shek ' s nationalists . On December 13 of that same year , the Nationalist capital of Nanking surrendered to Japanese troops . In the event known as the " Nanking Massacre " , Japanese troops massacred a large number of the defending garrison . It is estimated that as many as 300 , 000 people , including civilians , may have been killed , although the actual numbers are uncertain and the government of the People ' s Republic of China has never undertaken a full accounting of the massacres . In total , an estimated 20 million Chinese , mostly civilians , were killed during World War II . A puppet state was also set up in China quickly afterwards , headed by Wang Jingwei . The second Sino - Japanese war continued into World War II with the Communists and Nationalists in a temporary and uneasy nominal alliance against the Japanese . Clashes with the Soviet Union . In 1938 , the Japanese 19th Division entered territory claimed by the Soviet Union , leading to the Battle of Lake Khasan . This incursion was founded in the Japanese belief that the Soviet Union misinterpreted the demarcation of the boundary , as stipulated in the Treaty of Peking , between Imperial Russia and Manchu China ( and subsequent supplementary agreements on demarcation ) , and furthermore , that the demarcation markers were tampered with . On May 11 , 1939 , in the Nomonhan Incident " ( Battle of Khalkhin Gol ) " , a Mongolian cavalry unit of some 70 to 90 men entered the disputed area in search of grazing for their horses , and encountered Manchukuoan cavalry , who drove them out . Two days later the Mongolian force returned and the Manchukoans were unable to evict them . The Japanese IJA 23rd Division and other units of the Kwantung Army then became involved . Joseph Stalin ordered Stavka , the Red Army ' s high command , to develop a plan for a counterstrike against the Japanese . In late August , Georgy Zhukov employed encircling tactics that made skillful use of superior artillery , armor , and air forces ; this offensive nearly annihilated the 23rd Division and decimated the IJA 7th Division . On September 15 an armistice was arranged . Nearly two years later , on April 13 , 1941 , the parties signed a Neutrality Pact , in which the Soviet Union pledged to respect the territorial integrity and inviolability of Manchukuo , while Japan agreed similarly for the Mongolian People ' s Republic . Tripartite Pact . In 1938 , Japan prohibited the expulsion of the Jews in Japan , Manchuria , and China in accordance with the spirit of racial equality on which Japan had insisted for many years . The Second Sino - Japanese War had seen tensions rise between Imperial Japan and the United States ; events such as the Panay incident and the Nanking Massacre turned American public opinion against Japan . With the occupation of French Indochina in the years of 1940 – 41 , and with the continuing war in China , the United States placed embargoes on Japan of strategic materials such as scrap metal and oil , which were vitally needed for the war effort . The Japanese were faced with the option of either withdrawing from China and losing face or seizing and securing new sources of raw materials in the resource - rich , European - controlled colonies of South East Asia — specifically British Malaya and the Dutch East Indies ( modern - day Indonesia ) . On September 27 , 1940 , Imperial Japan signed the Tripartite Pact with Nazi Germany and Fascist Italy . Their objectives were to " establish and maintain a new order of things " in their respective world regions and spheres of influence , with Nazi Germany in Europe , Imperial Japan in Asia , and Fascist Italy in North Africa . The signatories of this alliance become known as the Axis Powers . The pact also called for mutual protection — if any one of the member powers was attacked by a country not already at war , excluding the Soviet Union — and for technological and economic cooperation between the signatories . For the sake of their own people and nation , Prime Minister Konoe formed the Taisei Yokusankai ( Imperial Rule Assistance Association ) on October 12 , 1940 as their own ruling party in Japan , avoiding the influences of German Nazism and Italian Fascism . Pacific War . In the Pacific War , many of the islands became dominions of the Empire . Attack on Pearl Harbor . Facing an oil embargo by the United States as well as dwindling domestic reserves , the Japanese government decided to execute a plan developed by the military branch largely led by Osami Nagano and Isoroku Yamamoto to bomb the United States naval base in Hawaii , thereby bringing the United States to World War II on the side of the Allies . On September 4 , 1941 , the Japanese Cabinet met to consider the war plans prepared by Imperial General Headquarters , and decided : Our Empire , for the purpose of self - defense and self - preservation , will complete preparations for war . . . < nowiki > [ < / nowiki > and is < nowiki > ] < / nowiki > . . . resolved to go to war with the United States , Great Britain and the Netherlands if necessary . Our Empire will concurrently take all possible diplomatic measures vis - a - vis the United States and Great Britain , and thereby endeavor to obtain our objectives . . . In the event that there is no prospect of our demands being met by the first ten days of October through the diplomatic negotiations mentioned above , we will immediately decide to commence hostilities against the United States , Britain and the Netherlands . The Imperial Japanese Navy made its surprise attack on Pearl Harbor , Oahu , Hawaii , on Sunday morning , December 7 , 1941 . The Pacific Fleet of the United States Navy and its defending Army Air Forces and Marine air forces sustained significant losses . The primary objective of the attack was to incapacitate the United States long enough for Japan to establish its long - planned Southeast Asian empire and defensible buffer zones . The U . S . public saw the attack as a treacherous act and rallied against the Empire of Japan . The United States entered the European Theatre and Pacific Theater in full force . Four days later , Adolf Hitler of Nazi Germany declared war on the United States , merging the separate conflicts . Japanese offensives ( 1941 – 42 ) . Following the attack on Pearl Harbor , the Japanese launched offensives against Allied forces in South East Asia , with simultaneous attacks on Hong Kong , British Malaya and the Philippines . The South - East Asian Campaign was preceded by years of propaganda and espionage activities carried out in the region by the Japanese Empire . The Japanese espoused their vision of a Greater Asian Co - Prosperity Sphere , and an Asia for Asians to the people of South East Asia , who had lived under European rule for generations . As a result , many inhabitants in the region actually sided with the Japanese invaders - except of course for the ethnic Chinese , who had witnessed the effects of a Japanese occupation in their homeland . Hong Kong surrendered to the Japanese on 25 December . In Malaya the Japanese overwhelmed an Allied army composed of British , Indian , Australian and Malay forces . The Japanese were quickly able to advance down the Malayan Peninsula , forcing the Allied forces to retreat towards Singapore . The Allies lacked aircover and tanks ; the Japanese had total air superiority . The sinking of HMS " Prince of Wales " and HMS " Repulse " on December 10 , 1941 led to the east coast of Malaya being exposed to Japanese landings and the elimination of British naval power in the area . By the end of January 1942 , the last Allied forces crossed the strait of Johore and into Singapore . In the Philippines , the Japanese pushed the combined Filipino - American force towards the Bataan peninsula and later the island of Corregidor . By January 1942 , General Douglas MacArthur and President Manuel L . Quezon were forced to flee in the face of Japanese advance . This marked among one of the worst defeats suffered by the Americans , leaving over 70 , 000 American and Filipino prisoners of war in the custody of the Japanese . On February 15 , 1942 , Singapore , due to the overwhelming superiority of Japanese forces and encirclement tactics , fell to the Japanese , causing the largest surrender of British - led military personnel in history . An estimated 80 , 000 Indian , Australian and British troops were taken as prisoners of war , joining 50 , 000 taken in the Japanese invasion of Malaya ( modern day Malaysia ) . Many were later used as forced labour constructing the Burma Railway , the site of the infamous Bridge on the River Kwai . Immediately following their invasion of British Malaya , the Japanese military carried out a purge of the Chinese population in Malaya and Singapore . Over the course of a month following their victory at Singapore , the Japanese are believed to have killed tens of thousands of ethnic Chinese perceived to be hostile to the new regime . The Japanese then seized the key oil production zones of Borneo , Central Java , Malang , Cepu , Sumatra , and Dutch New Guinea of the late Dutch East Indies , defeating the Dutch forces . They were welcomed ecstatically as liberating heroes by the oppressed Indonesian natives pursuant to their indigenous legends . The Japanese then consolidated their lines of supply through capturing key islands of the Pacific , including Guadalcanal . Path to defeat ( 1942 – 45 ) . Japanese military strategists were keenly aware of the unfavorable discrepancy between the industrial potential of the Japanese Empire and that of the United States . Because of this they reasoned that Japanese success hinged on their ability to extend the strategic advantage gained at Pearl Harbor with additional rapid strategic victories . The Japanese Command reasoned that only decisive destruction of the United States ' Pacific Fleet and conquest of its remote outposts would ensure that the Japanese Empire would not be overwhelmed by America ' s industrial might . In May 1942 , failure to decisively defeat the Allies at the Battle of the Coral Sea , in spite of Japanese numerical superiority , equated to a strategic defeat for Imperial Japan . This setback was followed in June 1942 by the catastrophic loss of a four carrier task force at the Battle of Midway . Midway was a decisive defeat for the Imperial Japanese Navy , and proved to be the turning point of the war . Australian land forces defeated Japanese Marines in New Guinea at the Battle of Milne Bay in September 1942 , which was the first land defeat suffered by the Japanese in the Pacific . Further defeats by the Allies at Guadalcanal in September 1942 , and New Guinea in 1943 put the Empire of Japan on the defensive for the remainder of the war . During 1943 and 1944 , Allied forces , backed by the industrial might and vast raw material resources of the United States , advanced steadily towards Japan . The Sixth United States Army , led by General MacArthur , landed on Leyte on 20 October 1944 . In the subsequent months , during the Philippines Campaign ( 1944 – 45 ) , the combined United States forces , together with the native guerrilla units , liberated the Philippines . By 1944 , the Allies had seized or bypassed and neutralized many of Japan ' s strategic bases through amphibious landings and bombardment . This , coupled with the losses inflicted by Allied submarines on Japanese shipping routes began to strangle Japan ' s economy and undermine its ability to supply its army . By early 1945 , the U . S . Marines had wrested control of the Ogasawara Islands in several hard - fought battles such as the Battle of Iwo Jima , marking the beginning of the fall of the islands of Japan . Atomic bombings of Hiroshima and Nagasaki . After securing airfields in Saipan and Guam in the summer of 1944 , the United States Army Air Forces undertook an intense bombing campaign , using incendiary bomb s , burning Japanese cities in an effort to pulverize Japan ' s industry and shatter its morale . These campaigns , peaking on the night of March 9 – 10 , 1945 in Tokyo during Operation Meetinghouse , led to the deaths of hundreds of thousands of civilians . Concurrent to these attacks , Japan ' s vital coastal shipping operations were severely hampered with extensive aerial mining by the US ' Operation Starvation . Regardless , these efforts did not succeed in persuading the Japanese military to surrender . In mid - August 1945 , the United States dropped nuclear weapon s on Japan . These atomic bombings were the first and only used against another nation . These two bombs killed approximately 100 , 000 to 200 , 000 people in a matter of minutes , and as many again died as a result of nuclear radiation in the following weeks , months and years . The bombs killed as many as 140 , 000 people in Hiroshima and 80 , 000 in Nagasaki by the end of 1945 . Defeat and surrender . Having ignored ( mokusatsu ) the Potsdam Declaration , the Empire of Japan surrendered and ended World War II , after the atomic bombings of Hiroshima and Nagasaki and a declaration of war by the Soviet Union . In a national radio address on 15 August , Emperor Hirohito announced the surrender to the Japanese people . After World War II . Occupation of Japan . A period known as Occupied Japan followed after the war , largely spearheaded by United States General of the Army Douglas MacArthur to revise the Japanese constitution and de - militarize Japan . The American occupation , with economic and political assistance , continued well into the 1950s . Allied forces ordered Japan to abolish the Meiji Constitution and enforce the Constitution of Japan , then rename the Empire of Japan as Japan on May 3 , 1947 . Japan adopted a parliamentary - based political system , while the Emperor changed to symbolic status . American General of the Army Douglas MacArthur later commended the new Japanese government that he helped establish and the new Japanese period when he was about to send the American forces to the Korean War : For historian John W . Dower , however , Repatriation . There was a significant level of emigration to the overseas territories of the Japanese Empire during the Japanese colonial period , including Korea , Taiwan , Manchuria , and Karafuto . Unlike emigrants to the Americas , Japanese going to the colonies occupied a higher rather than lower social niche upon their arrival . In 1938 , there were 309 , 000 Japanese in Taiwan . By the end of World War II , there were over 850 , 000 Japanese in Korea and more than 2 million in China , most of whom were farmers in Manchukuo ( the Japanese had a plan to bring in 5 million Japanese settlers into Manchukuo ) . In the census of December 1939 , the total population of the South Pacific Mandate was 129 , 104 , of which 77 , 257 were Japanese . By December 1941 , Saipan had a population of more than 30 , 000 people , including 25 , 000 Japanese . There were over 400 , 000 people living on Karafuto ( southern Sakhalin ) when the Soviet offensive began in early August 1945 . Most were of Japanese or Korean extraction . When Japan lost the Kuril Islands , 17 , 000 Japanese were expelled , most from the southern islands . After World War II , most of these overseas Japanese repatriated to Japan . The Allied powers repatriated over 6 million Japanese nationals from colonies and battlefields throughout Asia . Only a few remained overseas , often involuntarily , as in the case of orphans in China or prisoners of war captured by the Red Army and forced to work in Siberia . War crimes . Many political and military Japanese leaders were convicted for war crimes before the Tokyo tribunal and other Allied tribunals in Asia . However , all members of the imperial family implicated in the war , such as Emperor Shōwa and his brothers , cousins and uncles such as Prince Chichibu , Prince Fushimi Hiroyasu and Prince Asaka Yasuhiko , were exonerated from criminal prosecutions by Douglas MacArthur . The Japanese military before and during World War II committed numerous atrocities against civilian and military personnel . Large scale massacres , rapes and looting against civilians were committed most notably the Sook Ching and Nanking Massacre , and the use of around 200 , 000 " comfort women " , who were forced to serve as prostitutes for the Japanese military . The Imperial Japanese Army also engaged in the execution and harsh treatment of Allied military personnel and POW s and biological experiments were conducted by Unit 731 on civilians and prisoners of war ; this included the use of biological and chemical weapons authorized by Emperor Shōwa himself . According to the 2002 " International Symposium on the Crimes of Bacteriological Warfare " , the number of people killed in Far East Asia by the Imperial Japanese Army germ warfare and human experiments was estimated to be around 580 , 000 . Shirō Ishii and all Unit 731 members received immunity from U . S . General Douglas MacArthur in exchange for germ warfare data based on human experimentation . Influential personnel . Political . In the administration of Japan dominated by the military political movement during World War II , the civil central government was under the management of military men and their right - wing civilian allies , along with members of the nobility and Imperial Family . The Emperor was in the center of this power structure as supreme Commander - in - Chief of the Imperial Armed Forces and head of state . Military . The military of Imperial Japan was divided into two main branches under Imperial General Headquarters responsible for the overall conduct of operations including prominent military leaders and commanders . Prominent generals and leaders :