List of districts of the House of Representatives of Japan

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. == Redistricting and reapportionment ==

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 (Tōhoku, N. Kantō, Kinki, Kyūshū). 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. ==Hokkaidō (8 block seats)==

The block constituency for Hokkaidō (比例北海道ブロック) elects 8 members proportionally. It contains only Hokkaidō Prefecture, which is divided into 12 single-member districts. ===Hokkaidō Prefecture (12 districts)=== == Tohoku (12 block seats) ==

The block constituency for Tohoku (比例東北ブロック) elects 14 members proportionally. It corresponds to the Tohoku region. === Akita Prefecture (3 districts) === === Aomori Prefecture (3 districts) === === Fukushima Prefecture (4 districts) === === Iwate Prefecture (3 districts) === === Miyagi Prefecture (5 districts) === === Yamagata Prefecture (3 districts) === == Kita- (North) Kanto (19 block seats) ==

The Northern Kanto proportional representation block (北関東) elects 20 members proportionally. It includes four prefectures in northern Kanto. === Gunma Prefecture (5 districts) === === Ibaraki Prefecture (7 districts) === === Saitama Prefecture (16 districts) === === Tochigi Prefecture (5 districts) === == Minami- (Southern) Kanto (23 block seats) ==

The block constituency for southern Kanto (比例南関東ブロック, hirei minami-Kantō burokku) elects 22 members proportionally. It includes two prefectures in southern Kanto and one in eastern Chubu. === Chiba Prefecture (14 districts) === === Kanagawa Prefecture (20 districts) === === Yamanashi Prefecture (2 districts) === == Tokyo (19 block seats) ==

The block constituency for Tokyo (比例東京ブロック) elects 17 members proportionally. It covers Tokyo prefecture. === Tokyo Metropolis (30 districts) === == Hokuriku-Shin'etsu (10 block seats) ==

The block constituency for Hokuriku-Shin'etsu (北陸信越) elects 11 members proportionally. It combines five prefectures of the Hokuriku and Shin'etsu subregions in northern Chubu. === Fukui Prefecture (2 districts) === === Ishikawa Prefecture (3 districts) === === Niigata Prefecture (5 districts) === === Nagano Prefecture (5 districts) === === Toyama Prefecture (3 districts) === == Tokai (21 block seats) ==

The block constituency for Tokai (東海) elects 21 members proportionally. It covers three prefectures in southern Chubu, as well as one prefecture in Kinki. === Aichi Prefecture (16 districts) === === Gifu Prefecture (5 districts) === === Mie Prefecture (4 districts) === === Shizuoka Prefecture (8 districts) === == Kinki/Kansai (28 block seats) ==

The block constituency for Kinki (Kansai) (近畿) elects 29 members proportionally. It corresponds to the Kinki region minus Mie Prefecture. === Hyōgo Prefecture (12 districts) === === Kyoto Prefecture (6 districts) === === Nara Prefecture (3 districts) === === Osaka Prefecture (19 districts) === === Shiga Prefecture (3 districts) === === Wakayama Prefecture (2 districts) === == Chugoku (10 block seats) ==

The block constituency for Chugoku (中国) elects 11 members proportionally. It corresponds to the Chugoku region. === Hiroshima Prefecture (6 districts) === === Okayama Prefecture (4 districts) === === Shimane Prefecture (2 districts) === === Tottori Prefecture (2 districts) === === Yamaguchi Prefecture (3 districts) === == Shikoku (6 block seats) ==

The block constituency for Shikoku (比例四国ブロック) elects 6 members proportionally. It corresponds to the Shikoku region. === Ehime Prefecture (3 districts) === === Kagawa Prefecture (3 districts) === === Kōchi Prefecture (2 districts) === === Tokushima Prefecture (2 districts) === == Kyūshū (20 block seats) ==

The block constituency for Kyūshū (九州) elects 21 members proportionally. It includes all the prefectures on Kyūshū island, as well as Okinawa Prefecture. === Fukuoka Prefecture (11 districts) === === Kagoshima Prefecture (4 districts) === === Kumamoto Prefecture (4 districts) === === Miyazaki Prefecture (3 districts) === === Nagasaki Prefecture (3 districts) === === Ōita Prefecture (3 districts) === === Okinawa Prefecture (4 districts) === === Saga Prefecture (2 districts) === ==See also==