Japan adopted a constitution in 1947, based on three basic principles: sovereignty of the people, and respect for key human rights, and the rejection of war. The Constitution also provides for the independence of the three branches of government: legislative (Parliament), the Executive (Cabinet), and judicial (courts), and discussions are ongoing to amend the Constitution in order to strengthen Japan's role on the world stage.

The Japanese parliament, the highest authority in the state, is responsible for the preparation of legislation and regulations and consists of the House of Representatives (475 members) and councilors (242 members).

The House of Representatives shall elect the prime minister and approve  the public budget, while the House of Councilors will discuss the bills approved by the House of Representatives in advance to become laws after approval by the House.

The prime minister is  to form  the government and present it to the emperor to ratify it and then it is officially launched. The government is accountable to parliament in  performing the duties of the Executive power. The Prime Minister has the power to appoint and dismiss ministers. The Emperor is the symbol of the state and the unity of the people.