The Japanese political process has three types of elections: general elections to the House of Representatives held every four years (unless the lower house is dissolved earlier), elections to the House of Councillors held every three years to choose half of its members, and local elections held every four years for offices in prefectures and municipalities. Elections are supervised by Election Administration Commissions at each administrative level under the general direction of the Central Election Management Council, an extraordinary organ attached to the Ministry of Internal Affairs and Communications (MIC). The minimum voting age in Japan's non-compulsory electoral system was reduced from twenty to eighteen years in June 2016. Voters must satisfy a three-month residency requirement before being allowed to cast a ballot.