The National Diet (国会, Kokkai) is Japan's bicameral legislature. It is composed of a lower house that is called the House of Representatives, and an upper house, called the House of Councillors. Both houses of the Diet are directly elected under a parallel voting system. In addition to passing laws, the Diet is formally responsible for selecting the Prime Minister. The Diet was first convened as the Imperial Diet in 1889 as a result of adopting the Meiji Constitution. The Diet took its current form in 1947 upon the adoption of the postwar constitution and is considered by the Constitution to be the highest organ of state power.