## Overview The National Diet (Kokkai) is Japan’s national legislature and the cornerstone of its parliamentary democracy[1][4]. Established in its current form by the post-World War II Constitution in 1947, it replaced the Imperial Diet, which had operated since 1890 under the Meiji Constitution[1][7]. The Diet is a bicameral body, consisting of the House of Representatives (Shūgiin, the lower house) and the House of Councillors (Sangiin, the upper house), both directly elected by the public[1][4][5]. The Diet convenes in the iconic National Diet Building in Nagatachō, Tokyo, a structure completed in 1936 that symbolizes the nation’s democratic aspirations[1][6]. ## Functions and Powers The National Diet is Japan’s sole lawmaking body, responsible for passing legislation, approving the national budget, ratifying treaties, and formally designating the Prime Minister[1][4]. The House of Representatives, with 465 members serving up to four-year terms, holds greater legislative power—it can override decisions of the House of Councillors on most matters and plays a decisive role in selecting the Prime Minister and passing budget bills[4]. The House of Councillors, with 242 members elected to six-year terms (half elected every three years), acts as a stabilizing force, providing continuity and a long-term perspective, though its ability to block legislation is limited[4]. Both houses must cooperate to pass most laws, ensuring a system of checks and balances[4]. ## Historical Context Under the Meiji Constitution, the Imperial Diet was Japan’s first modern legislature, though its powers were constrained by the executive and the peerage-dominated upper house[2][5]. The post-war constitution transformed the Diet into the “highest organ of state power,” embedding it firmly within a democratic framework[4][7]. This shift marked a decisive break from Japan’s