The National Diet is the sole law-making organ of the State based on the Constitution promulgated in 1946. The Diet comprises two houses: The House of Representatives (the lower house) and the House of Councillors (the upper House). The House of Representatives has 480 members elected for a four-year term by a combination of single-seat constituency system and proportional representation. The Lower House may be dissolved at any time by the Emperor on the advice of the Prime Minister. The last general election for the House of Representatives took place in December 2014 upon the Prime Minister’s decision to dissolve the Lower House. The next Lower House election is expected to take place late 2018 unless it is dissolved. The House of Councillors (the Upper House) has 242 members, elected for a six-year term – every three years half of the Upper House members are elected. The last Upper House election took place in July 2016 and the next is expected for 2019.
Japan is a parliamentary cabinet system, and more than half of cabinet members are selected from MPs by the Prime Minister. The Prime Minister is elected by MPs through a resolution of the Diet. MPs and the Cabinet are qualified to submit bills, and all the bills are passed to a committee for deliberation, which sometimes includes open hearings. After the committee votes on the bill, it is passed for approval to Diet plenary session in both houses. If the two chambers’ votes are at odds, a conference committee is convened in an attempt to reach a compromise. After a law is passed it is promulgated by the Emperor and announced in the government gazette. The Diet also has the authority to approve the budget, ratify treaties and amend the Constitution.