List of districts of the House of Representatives of Japan
, the House of Representatives of Japan is elected from a combination of multi-member districts and single-member districts, a method called parallel voting. Currently, 176 members are elected from 11 multi-member districts by a party-list system of proportional representation, and 289 members are elected from single-member districts, for a total of 465. 233 seats are therefore required for a majority. Each PR block consists of one or more prefectures, and each prefecture is divided into one or more single-member districts. In general, the block districts correspond loosely to the major regions of Japan, with some of the larger regions subdivided.
History
Until the 1993 general election, all members of the House of Representatives were elected in multi-member constituencies by single non-transferable vote. In 1994, Parliament passed an electoral reform bill that introduced the current system of parallel voting in single-member constituencies and proportional voting blocks. The original draft bill in 1993 by the anti-LDP coalition of Prime Minister Morihiro Hosokawa included proportional party list voting on a national scale, an equal number of proportional and district seats and the possibility of split voting. However, the bill stalled in the House of Councillors. After the Liberal Democratic Party had returned to power later that year, it was changed to include proportional voting in regional blocks only, the number of proportional seats was reduced, but the possibility to cast two separate votes was kept in the bill. The electoral reform law was finally passed in 1994. It was first applied in the 1996 general election.Redistricting and reapportionment
Amendments to the electoral law in 2002 and 2013 changed the boundaries of single-member districts and reapportioned seats between prefectures. The borders of the regional proportional blocks have never changed, but the apportionment of seats to the regional proportional blocks changed in 2000 after the number of proportional seats had been reduced from 200 to 180, and in the 2002 reapportionment.Another reapportionment was passed by the National Diet in June 2017. In the majoritarian segment, it will change 97 districts in 19 prefectures, six are eliminated without replacement. In the proportional segment, four "blocks" lose a seat each. Thus, the number of majoritarian seats is reduced to 289, the number of proportional seats to 176, the House of Representatives overall shrinks to 465. The reform took effect one month after promulgation, on July 16, 2017.