Suffrage:
20 years of age; universal
Executive branch:
chief of state: Emperor AKIHITO (since 7 January 1989)
head of government: Prime Minister Yukio HATOYAMA (since 16 September 2009); Deputy Prime Minister Naoto KAN (since 16 September 2009)
cabinet: Cabinet appointed by the prime minister
elections: Diet designates prime minister; constitution requires that prime minister commands parliamentary majority; following legislative elections, leader of majority party or leader of majority coalition in House of Representatives usually becomes prime minister; monarch is hereditary
Legislative branch:
bicameral Diet or Kokkai consists of the House of Councillors or Sangi-in (242 seats - members elected for fixed six-year terms; half reelected every three years; 146 members in multi-seat constituencies and 96 by proportional representation) and the House of Representatives or Shugi-in (480 seats - members elected for maximum four-year terms; 300 in single-seat constituencies; 180 members by proportional representation in 11 regional blocs); the prime minister has the right to dissolve the House of Representatives at any time with the concurrence of the cabinet.
elections: House of Councillors - last held 29 July 2007 (next to be held in July 2010); House of Representatives - last held 30 August 2009 (next to be held by August 2013)