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 Meiji Constitution of 1889. The constitution consists of a preamble and 103 articles grouped into 11 chapters. It is based on the principles of popular sovereignty, with the Emperor of Japan as the symbol of the state; the renunciation of war; individual rights; and the prohibition of state religion.
Upon the surrender of Japan at the end of the war in 1945, Japan was occupied and U.S. General Douglas MacArthur, the Supreme Commander for the Allied Powers, directed Prime Minister Kijūrō Shidehara to draft a new constitution. Shidehara created a committee of Japanese scholars for the task, but MacArthur reversed course in February 1946 and presented a draft created under his own supervision, which was reviewed and modified by the scholars before its adoption. Also known as the "MacArthur Constitution", "Post-war Constitution" (戦後憲法, Sengo-Kenpō), or "Peace Constitution" (平和憲法, Heiwa-Kenpō), it is relatively short at 5,000 signs, less than a quarter the length of the average national constitution if one compares it with constitutions written in alphabetical word-based languages.
The constitution provides for a parliamentary system and three branches of government, with the National Diet (legislative), Cabinet led by a Prime Minister (executive), and Supreme Court (judicial) as the highest bodies of power. It guarantees individual rights, including legal equality; freedom of assembly, association, and speech; due process; and fair trial. In contrast to the Meiji Constitution, which invested the emperor with supreme political power, under the 1946 constitution his role in the system of constitutional monarchy is reduced to "the symbol of the State and of the unity of the people", and he exercises only a ceremonial role under popular sovereignty. Article 9 of the constitution renounces Japan's right to wage war and to maintain military forces. Despite this, it retains a de facto military in the form of the Self-Defense Forces and hosts a substantial U.S. military presence. Amendments to the constitution require a two-thirds vote in both houses of the National Diet and approval in a referendum, and despite the efforts of conservative and nationalist forces to revise Article 9 in particular, it remains the world's oldest un-amended supreme constitutional text.
The Meiji Constitution was the fundamental law of the Empire of Japan, propagated during the reign of Emperor Meiji (r. 1867–1912). It provided for a form of mixed constitutional and absolute monarchy, based on the Prussian and British models. In theory, the Emperor of Japan was the supreme leader, and the cabinet, whose prime minister was elected by a privy council, were his followers; 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 accountable to the Emperor, rather than to the elected members of the Imperial Diet.
On 26 July 1945, shortly before the end of World War II, Allied leaders of the United States (President Harry S. Truman), the United Kingdom (Prime Minister Winston Churchill), and the Republic of China (President Chiang Kai-shek) issued the Potsdam Declaration. The Declaration demanded Japanese military's unconditional surrender, demilitarisation and democratisation.
The declaration defined the major goals of the post-surrender Allied occupation: "The Japanese Government shall remove all obstacles to the revival and strengthening of democratic tendencies among the Japanese people. Freedom of speech, of religion, and of thought, as well as respect for the fundamental human rights shall be established" (Section 10). In addition, "The occupying forces of the Allies shall be withdrawn from Japan as soon as these objectives have been accomplished and there has been established in accordance with the freely expressed will of the Japanese people a peacefully inclined and responsible government" (Section 12). The Allies sought not merely punishment or reparations from a militaristic foe, but fundamental changes in the nature of its political system. In the words of a political scientist Robert E. Ward: "The occupation was perhaps the single most exhaustively planned operation of massive and externally directed political change in world history."
The Japanese government, Prime Minister Kantarō Suzuki's administration and Emperor Hirohito accepted the conditions of the Potsdam Declaration, which necessitates amendments to its Constitution after the surrender.
The wording of the Potsdam Declaration—"The Japanese Government shall remove all obstacles ..."—and the initial post-surrender measures taken by MacArthur, suggest that neither he nor his superiors in Washington intended to impose a new political system on Japan unilaterally. Instead, they wished to encourage Japan's new leaders to initiate democratic reforms on their own. But by early 1946, MacArthur's staff and Japanese officials were at odds over the most fundamental issue, the writing of a new Constitution. Emperor Hirohito, Prime Minister Kijūrō Shidehara, and most of the cabinet members were extremely reluctant to take the drastic step of replacing the 1889 Meiji Constitution with a more liberal document.
Former prime minister Fumimaro Konoe, Shidehara Cabinet and the civil constitutional study groups formed original constitutions. The formal draft constitution, which was created by the Shidehara Cabinet, was rejected by GHQ and the government reviewed the revised drafts by various political parties and accepted liberal ways of thinking especially toward the emperor as the symbol of nationals and dispossession of a military power.
After World War II, the Allied Powers concluded an "Instrument of Surrender" with Japan, which stated that "the Emperor and the Government of Japan shall come under the subordination of the Supreme Commander of the Allied Powers". Koseki interprets this statement as the GHQ's indirect rule through the Emperor and the Japanese government, rather than direct rule over the Japanese people. In other words, GHQ regarded the Emperor Hirohito not as a war criminal parallel to Hitler and Mussolini but as one governance mechanism.
The Japanese government at the end of World War II was organized by Higashikuni Cabinet (Prime Minister Prince Naruhiko Higashikuni), with Fumimaro Konoe, who had served as the prime minister during the Manchurian Incident in 1931, as a minister without portfolio. The trigger of constitutional amendment was from GHQ General MacArthur's word to Fumimaro Konoe. After an unsuccessful first visit on 13 September 1945, Fumimaro Konoe paid another visit to MacArthur at the GHQ headquarters on 4 October 1945. Although the GHQ later denied this fact, citing a mistake by the Japanese interpreter, diplomatic documents between Japan and the U.S. state that "the Constitution must be amended to fully incorporate liberal elements". "At the meeting, the General told Konoe that the Constitution must be amended". In this regard, it can be said that the GHQ granted Konoe the authority to amend the Constitution. However, at this point, the Higashikuninomiya Cabinet was succeeded by the Shidehara Cabinet, and Jōji Matsumoto, the then Minister of State, stated that the Cabinet should be the only one to amend the Constitution, and the Constitutional Problems Investigation Committee was established. In other words, there was a conflict between the Konoe and Shidehara cabinets as to who should take the initiative in constitutional amendment.
However, this conflict ended with Konoe being nominated as a candidate for Class A war criminal due to domestic and international criticism. To begin with, Konoe was able to have the initiative to amend the Constitution because he had been assigned full-time by the GHQ to amend the constitution, although he was not an unappointed minister when the cabinet was changed. However, due to domestic and foreign criticism of Konoe, the GHQ announced on 1 November that Konoe had not been appointed to amend the Constitution and that he had no authority to lead the amendment of the constitution since the cabinet had changed. At that time, Konoe belonged to the Office of the Minister of the Interior, which was in charge of politics related to the Imperial Household, but since the Office of the Minister of the Interior was about to be abolished, he decided to submit a proposal for amendment before then. Konoe's proposal reflected the wishes of the GHQ and was very liberal in content, including "limitation of the imperial prerogative", "independent dissolution of the Diet", and "freedom of speech", but it was never finally approved as a draft, and Konoe committed suicide by poisoning himself. After this, the authority to amend the Constitution was completely transferred to Shidehara's cabinet.