The legal age for voting is 20, while the minimum age to stand for election is 25 for the lower house and 30 for the upper house.
There are 252 Councillors elected for 6 years and 480 Representatives elected for 4 years.
Both chambers are elected by a combination of proportional representation and prefectural constituencies. 100 Councillors and 180 Representatives are elected by proportional representation, and the rest by district (47 prefectures for the Councillors, and 300 single-seat electoral districts for the Representatives).
Oddly enough, Japanese laws prohibit candidates to make written propaganda during the electoral periods - which means that also Internet campaigns or are not allowed. As a result, politicians have to resort to shouting in loudspeakers in little vans while driving around their electoral constituencies. The resulting din causes much nuisance the residents, especially since what they say is rarely more than "I am Mr/Ms X, please vote for me, thank you !". Very little political ideas are actually communicated, which is probably the aim of this policy (as a means for the ruling LDP party to stay in power).