Constitution of Japan in the context of "Emperor of Japan"

The Government of Japan is the central government of Japan. It consists of legislative, executive and judiciary branches and functions under the framework established by the Constitution of Japan. Japan is a unitary state, containing forty-seven administrative divisions, with the emperor as its head of state. His role is ceremonial and he has no powers related to the Government. Instead, it is the Cabinet, comprising the prime minister and the ministers of state, that directs and controls the government and the civil service. The Cabinet has the executive power and is formed by the prime minister, who is the head of government. The Prime Minister is nominated by the National Diet and appointed to office by the Emperor. The current cabinet is the Takaichi Cabinet, which is led by prime minister Sanae Takaichi, who assumed office on 21 October 2025. The country has had a Liberal Democratic minority government since 2025.

The National Diet is the legislature, the organ of the Legislative branch. The Diet is bicameral, consisting of two houses with the House of Councilors being the upper house, and the House of Representatives being the lower house. The members of both houses of the Diet are directly elected by the people, who are the source of sovereignty. The Diet is defined as the supreme organ of sovereignty in the Constitution. The Supreme Court and other lower courts make up the Judicial branch and have all the judicial powers in the state. The Supreme Court has ultimate judicial authority to interpret the constitution and the power of judicial review. The judicial branch is independent from the executive and the legislative branches. Judges are nominated or appointed by the Cabinet and never removed by the executive or the legislature except during impeachment.

Japanese militarism (日本軍国主義, Nihon gunkoku shugi) was the ideology in the Empire of Japan which advocated the belief that militarism should dominate the political and social life of the nation, and the belief that the strength of the military is equal to the strength of a nation. It was most prominent from the start of conscription after the Meiji Restoration until the Japanese defeat in World War II, roughly 1873 to 1945. Since then, pacifism has been enshrined in the postwar Constitution of Japan as one of its key tenets.

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 August 1910 to September 1945, it included the Japanese archipelago, the Kurils, Karafuto, Korea, and Taiwan. The South Seas Mandate and concessions such as the Kwantung Leased Territory were de jure not internal parts of the empire but dependent territories. In the closing stages of World War II, with Japan defeated alongside the rest of the Axis powers, the formalized surrender was issued on September 2, 1945, in compliance with the Potsdam Declaration of the Allies, and the empire's territory subsequently shrunk to cover only the Japanese archipelago resembling modern Japan.

Under the slogans of "Enrich the Country, Strengthen the Armed Forces" and "Promote Industry" which followed the Boshin War and the restoration of power to the emperor from the shogun, Japan underwent a period of large-scale industrialization and militarization, often regarded as the fastest modernization of any country to date. All of these aspects contributed to Japan's emergence as a great power following the First Sino-Japanese War, the Boxer Rebellion, the Russo-Japanese War, and World War I. Economic and political turmoil in the 1920s, including the Great Depression, led to the rise of militarism, nationalism, statism and authoritarianism, during which Japan joined the Axis alliance with Nazi Germany and Fascist Italy, conquering a large part of the Asia–Pacific; during this period, the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) committed numerous atrocities and war crimes, including the Nanjing Massacre. There has been a debate over defining the political system of Japan as a dictatorship, which has been disputed due by the absence of a dictator, and over calling it fascist. The other suggested terms were para-fascism, militarism, corporatism, totalitarianism, and police state.

The National Diet (国会, Kokkai; Japanese pronunciation: [kok̚.kai]) is the national legislature of Japan. It is composed of a lower house, called the House of Representatives (衆議院, Shūgiin), and an upper house, the House of Councillors (参議院, Sangiin). Both houses are directly elected under a parallel voting system. In addition to passing laws, the Diet is formally responsible for nominating the prime minister. The Diet was first established as the Imperial Diet in 1890 under the Meiji Constitution, and took its current form in 1947 upon the adoption of the post-war constitution. Both houses meet in the National Diet Building (国会議事堂, Kokkai-gijidō) in Nagatachō, Chiyoda, Tokyo.

The House of Representatives (衆議院, Shūgiin; Japanese pronunciation: [ɕɯː.ɡʲiꜜ.iɴ, -ŋʲiꜜ-]) is the lower house of the National Diet of Japan. The House of Councillors is the upper house.The composition of the House is established by Article 41 [ja] and Article 42 [ja] of the Constitution of Japan. The House of Representatives has 465 members, elected for a four-year term. Of these, 176 members are elected from 11 multi-member constituencies by a party-list system of proportional representation, and 289 are elected from single-member constituencies.

The overall voting system used to elect the House of Representatives is a parallel system, a form of semi-proportional representation. Under a parallel system, the allocation of list seats does not take into account the outcome in the single seat constituencies. Therefore, the overall allocation of seats in the House of Representatives is not fullly proportional, to the advantage of larger parties.

The Supreme Court of Japan (最高裁判所, Saikō-Saibansho; called 最高裁 Saikō-Sai for short), located in Hayabusachō, Chiyoda, Tokyo, is the highest court in Japan. It has ultimate judicial authority to interpret the Japanese constitution and decide questions of national law. It has the power of judicial review, which allows it to determine the constitutionality of any law or official act.

The Imperial House (皇室, Kōshitsu) is the reigning dynasty of Japan, consisting of those members of the extended family of the reigning emperor of Japan who undertake official and public duties. Under the present constitution of Japan, the emperor is "the symbol of the State and of the unity of the people". Other members of the imperial family perform ceremonial and social duties, but have no role in the affairs of government. The duties as an emperor are passed down the line to their male children. The Japanese monarchy is the oldest continuous hereditary monarchy in the world. The imperial dynasty does not have a name, therefore its direct members do not have a family name.

The Constitution of the Empire of Japan (Kyūjitai: 大日本帝國憲法; Shinjitai: 大日本帝国憲法, romanized: Dai-Nippon Teikoku Kenpō), known informally as the Meiji Constitution (明治憲法, Meiji Kenpō), was the constitution of the Empire of Japan which was proclaimed on February 11, 1889, and remained in force between November 29, 1890, until May 2, 1947. Enacted after the Meiji Restoration in 1868, it provided for a form of mixed constitutional and absolute monarchy, based jointly on the German and British models. In theory, the Emperor of Japan governed the empire with the advice of his ministers; in practice, the Emperor was head of state but the Prime Minister was the actual head of government. Under the Meiji Constitution, the Prime Minister and his Cabinet were not necessarily chosen from the elected members of parliament.

During the Allied occupation of Japan, the Meiji Constitution was replaced with the "Postwar Constitution" on November 3, 1946; the latter document has been in force since May 3, 1947. In order to maintain legal continuity, the Postwar Constitution was enacted as an amendment to the Meiji Constitution.