Japan holds elections for following governing organs; the members of the House of Representatives (Shugiin) the members the House of Councillors (Sangiin) the Chief Executives of all local public entities the members of all local public assemblies
For elections, Japan uses following electoral methods:
The Plurality Vote
Under the Plurality Vote, people vote for a their favored candidate and the candidate who obtains the largest votes is elected to office.
The FirstPastThePost Vote (FPTP)
Under the First Past The Post Vote method, people vote for a their favored candidate and the candidate who obtains the largest votes is elected to office in each constituency
The Single NonTransferable Vote (SNTV)
Under the Single NonTransferable Vote method, people vote for a their favored candidate and the candidates who obtain the largest votes, up to the allocated seats to be filled, are elected to office in each constituency.
The Proportional Representation
Under the Proportional Representation method, people vote for a their favored party and the seats are distributed to each party depends on their proportion of votes to total votes in each constituency.
For the election of the House of Representatives that consists of 495 members, the First Past The Post Vote and the party list proportional representation are used as electoral methods. 295 members are elected in 295 constituencies by the First Past The Post Vote and the remaining 180 members are elected in 11 electoral blocs by the Proportional Representation.
For the election of the House of Councillors that consists of 242 members, the Single Non-Transferable Vote and the party list proportional representation are used as electoral methods. 146 members are elected in 47 prefectural constituencies by the Single Non-Transferable Vote and the remaining 96 members are elected on a nationwide basis by the party list proportional representation.
For the elections of the Chief Executives of all local public entities, the Plurality Vote is used as an electoral method. On the other hand, the First Past The Post Vote and/or the Single Non-Transferable Vote are used as electoral methods for the members of all local public assemblies.
Resources :
PDF : Election System in Japan (2007)
PDF : Japanese Election System– Election Administration Organization (Tokyo Metropolitan Government Election Administration Commission)
Link : Electoral System: Shugiin (House of Representatives) (IPU)
Link : Electoral System: Sangiin (House of Councillors) (IPU)
Link : Electoral System (Country Studies)