, 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 (called proportional representation blocks or PR blocks) by a party-list system of proportional representation (PR), 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 (such as Kantà Â) subdivided.
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 (250 each) and the possibility of split voting. However, the bill stalled in the House of Councillors. After the Liberal Democratic Party (LDP) 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.
Amendments to the electoral law in 2002 and 2013 changed the boundaries of single-member districts and reapportioned seats between prefectures (+5/-5 in 2002; +0/-5 in 2013, resulting in a net change of -5 in district seats in the House of Representatives to 295 and overall seats to 475). 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 (reducing the total number of seats in the lower house from 500 to 480), 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 (one each in Aomori, Iwate, Mie, Nara, Kumamoto and Kagoshima). In the proportional segment, four "blocks" lose a seat each (Tà Âhoku, N. Kantà Â, Kinki, Kyà «shà «). 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.
Based on a legal amendment in 2016, the number of electoral districts in each prefecture is currently apportioned according to the Adams method in proportion to the number of voters in the prefecture in the large-scale census conducted every 10 years. Based on the first large-scale census conducted in 2020 after the legal amendment, the single-seat constituency boundaries were revised in the 2022 Election Law amendment. Ten prefectures (Miyagi, Fukushima, Niigata, Shiga, Wakayama, Okayama, Hiroshima, Yamaguchi, Ehime, and Nagasaki) lost one constituency each, while Saitama, Chiba, and Aichi each gained one, Kanagawa gained two, and Tokyo gained five.
The block constituency for Hokkaidà  (æ¯Âä¾ÂÃ¥ÂÂæµ·éÂÂãÂÂãÂÂãÂÂã¯) elects 8 members proportionally. It contains only Hokkaidà  Prefecture, which is divided into 12 single-member districts.
The block constituency for Tohoku (æ¯Âä¾Âæ±åÂÂãÂÂãÂÂãÂÂã¯) elects 14 members proportionally. It corresponds to the Tohoku region.
The Northern Kanto proportional representation block (Ã¥ÂÂé¢æ±) elects 20 members proportionally. It includes four prefectures in northern Kanto.
The block constituency for southern Kanto (æ¯Âä¾ÂÃ¥ÂÂé¢æ±ãÂÂãÂÂãÂÂã¯, hirei minami-Kantà  burokku) elects 22 members proportionally. It includes two prefectures in southern Kanto and one in eastern Chubu.
The block constituency for Tokyo (æ¯Âä¾Âæ±京ãÂÂãÂÂãÂÂã¯) elects 17 members proportionally. It covers Tokyo prefecture.
The block constituency for Hokuriku-Shin'etsu (Ã¥ÂÂé¸信è¶Â) elects 11 members proportionally. It combines five prefectures of the Hokuriku and Shin'etsu subregions in northern Chubu.
The block constituency for Tokai (æ±海) elects 21 members proportionally. It covers three prefectures in southern Chubu, as well as one prefecture in Kinki.
The block constituency for Kinki (Kansai) (è¿Âç¿) elects 29 members proportionally. It corresponds to the Kinki region minus Mie Prefecture.
The block constituency for Chugoku (ä¸Âå½) elects 11 members proportionally. It corresponds to the Chugoku region.
The block constituency for Shikoku (æ¯Âä¾ÂÃ¥ÂÂå½ãÂÂãÂÂãÂÂã¯) elects 6 members proportionally. It corresponds to the Shikoku region.
The block constituency for Kyà «shà « (ä¹Âå·Â) elects 21 members proportionally. It includes all the prefectures on Kyà «shà « island, as well as Okinawa Prefecture.