, 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 Kantō) 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 (250 each) and the possibility of split voting. However, the bill stalled in the House of Councillors.CRS: Issue Brief IB93100 in the Government Document Digital Collection of the University of North Texas 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 2002MIC: 衆議院小選挙区の区割りの改定等について and 2013MIC: 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),MIC: 衆議院比例代表選出議員の定数削減について 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.MIC: 衆議院小選挙区の区割りの改定等についてNHK Senkyo Web: 衆院小選挙区 区割り見直し 改正公選法が成立
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.MIC: 衆議院議員選挙区画定審議会設置法及び公職選挙法の一部を改正する法律 概要 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.「10増10減」とは 1票の格差是正、小選挙区の数変更. The Nikkei. Retrieved 2026-03-03.
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) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMapDistrict 1Sapporo, wards of Chūō-ku and Minami-ku, parts Nishi-ku and Kita-ku wards455,279Takahiro KatōLDPDistrict 2Sapporo, ward of Higashi-ku and part of Kita-ku ward459,952Yusuke TakahashiLDPDistrict 3Redistricted in 2022 (First effective in the 2024 Japanese General Election)Sapporo, wards of Toyohira-ku, Kiyota-ku and part of Shiroishi-ku ward462,546Hirohisa TakagiLDPDistrict 4Sapporo, ward of Teine-ku and part of Nishi-ku ward
Cities of Otaru and Ishikari
Shiribeshi Subprefecture398,852Hiroyuki NakamuraLDPDistrict 5Sapporo, ward of Atsubetsu-ku, part of Shiroishi-ku ward
Cities of Chitose, Ebetsu, Eniwa and Kitahiroshima
Ishikari Subprefecture428,845Yoshiaki WadaLDPDistrict 6Redistricted in 2002 (first effective in the 2003 House of Representatives election)Cities of Asahikawa, Furano, Nayoro and Shibetsu Kamikawa Subprefecture395,302Kuniyoshi AzumaLDPDistrict 7Cities of Kushiro and Nemuro Kushiro Subprefecture and Nemuro Subprefecture237,537Takako SuzukiLDPDistrict 8Cities of Hakodate and Hokuto Hiyama Subprefecture and Oshima Subprefecture339,230Jun MukōyamaLDPDistrict 9Cities of Date, Muroran, Noboribetsu and Tomakomai Hidaka Subprefecture and Iburi Subprefecture361,963Hideki MatsushitaLDPDistrict 10Cities of Akabira, Ashibetsu, Bibai, Fukagawa, Iwamizawa, Mikasa, Rumoi, Sunagawa, Takikawa and Utashinai Rumoi Subprefecture and Sorachi Subprefecture262,277Hiroshi KamiyaCRAJDistrict 11City of Obihiro Tokachi Subprefecture273,408Koichi NakagawaLDPDistrict 12Cities of Abashiri, Kitami, Monbetsu and Wakkanai Okhotsk Subprefecture and Sōya Subprefecture267,346Arata TakebeLDP
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) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtCity of Akita253,265Hiroyuki TogashiLDP2nd districtCities of Katagami, Kazuno, Kitaakita, Noshiro, Ōdate and Oga Districts of Kazuno, Kitaakita, Minamiakita and Yamamoto239,942Junji FukuharaLDP3rd districtCities of Daisen, Nikaho, Semboku, Yokote, Yurihonjō and Yuzawa Districts of Ogachi and Senboku299,529Toshihide MuraokaDPP
Aomori Prefecture (3 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMapDistrict 1Cities of Aomori and Mutsu District of Higashitsugaru, Shimokita and part of district of Kamikita323,705Jun TsushimaLDPDistrict 2Cities of Hachinohe, Misawa and Towada Part of district of Shimokita371,661Junichi KandaLDPDistrict 3Cities of Hirakawa, Hirosaki, Goshogawara, Kuroishi and Tsugaru Districts of Kitatsugaru, Minamitsugaru, Nakatsugaru and Nishitsugaru327,919Jiro KimuraLDP
Fukushima Prefecture (4 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMapDistrict 1Cities of Date, Fukushima, Motomiya and Nihonmatsu Districts of Date and Sōma376,502Naotoshi NishiyamaLDPDistrict 2Cities of Kōriyama, Sukagawa and Tamura
Districts of Iwase, Ishikawa and Tamura419,955Taku NemotoLDPDistrict 3Cities of Aizuwakamatsu, Kitakata and Shirakawa
District of Higashishirakawa, Kawanuma, Minamiaizu, Nishishirakawa, Ōnuma and Yama320,070Kentarō UesugiLDP4th DistrictCities of Iwaki, Minamisōma and Sōma
Districts of Futaba and Sōma392,434Ryūtarō SakamotoLDP
Iwate Prefecture (3 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtCity of MoriokaDistrict of Shiwa286,099Takeshi ShinaCRAJ2nd districtRedistricted in 2013 (first effective in the 2014 House of Representatives election)Cities of Hachimantai, Kamaishi, Kuji, Miyako, Ninohe, Ōfunato, Rikuzentakata, Takizawa, and TōnoDistricts of Iwate, Kamihei, Kesen, Kunohe, Ninohe, and Shimohei342,912Shun'ichi SuzukiLDP3rd districtCities of Hanamaki, Ichinoseki, Kitakami, and ŌshūDistricts of Isawa, Nishiiwai, and Waga360,309Takashi FujiwaraLDP
Miyagi Prefecture (5 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtSendai, wards of Aoba-ku and Taihaku-ku448,291Tōru DoiLDP2nd districtSendai, wards of Izumi-ku, Miyagino-ku and Wakabayashi-ku453,667Katsuyuki WatanabeLDP3rd districtCities of Iwanuma, Kakuda, Natori, and ShiroishiDistricts of Igu, Katta, Shibata, and Watari276,350Akihiro NishimuraLDP4th districtCities of Higashimatsushima, Ishinomaki, Shiogama, Tagajō, and TomiyaDistricts of Kurokawa, Miyagi, and Oshika379,938Chisato MorishitaLDP5th districtCities of Kesennuma, Kurihara, Ōsaki, and TomeDistricts of Kami, Motoyoshi, and Tōda332,993Itsunori OnoderaLDP
Yamagata Prefecture (3 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtCities of Kaminoyama, Tendō, and YamagataDistrict of Higashimurayama294,877Toshiaki EndoLDP2nd districtCities of Higashine, Murayama, Nagai, Nan'yō, Obanazawa, Sagae, and YonezawaDistricts of Higashiokitama, Kitamurayama, Nishimurayama, and Nishiokitama297,350Norikazu SuzukiLDP3rd districtCities of Sakata, Shinjō, and TsuruokaDistricts of Akumi, Higashitagawa, and Mogami270,727Ayuko KatoLDP
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) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtCities of Maebashi and NumataDistrict of Tone336,483Yasutaka NakasoneLDP2nd districtCities of Isesaki, Kiryū, and MidoriDistrict Sawa323,710Toshiro InoLDP3rd districtCities of Ōta and TatebayashiDistrict of Oura314,548Hiroyoshi SasakawaLDP4th districtCities of Fujioka and part of TakasakiDistrict of Tano290,465Tatsuo FukudaLDP5th districtCities of Annaka, Shibukawa, Tomioka, and part of TakasakiDistricts of Agatsuma, Kanra, and Kitagunma307,616Yūko ObuchiLDP
Ibaraki Prefecture (7 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtCities of Chikusei, Kasama, Mito, and Sakuragawa
District of Higashiibaraki (Town of Shirosato)416,696Yoshinori TadokoroLDP2nd districtCities of Hokota, Itako, Kashima, Kamisu, Namegata, and Omitama
District of Higashiibaraki (Towns of Ibaraki and Ōarai)295,363Fukushiro NukagaLDP3rd districtCities of Inashiki, Moriya, Ryūgasaki, Toride, and Ushiku
Districts of Inashiki and Kitasouma385,766Yasuhiro HanashiLDP4th districtCities of Hitachinaka, Hitachiōmiya, Hitachiōta, and Naka
District of Kuji262,114Hiroshi KajiyamaLDP5th districtCities of Hitachi, Kitaibaraki, and Takahagi District of Naka230,687Satoshi AsanoDPFP6th districtCities of Ishioka, Kasumigaura, Tsuchiura, Tsukuba, and Tsukubamirai455,564Ayano KunimitsuLDP7th districtCities of Bandō, Jōsō, Koga, Shimotsuma and Yūki
Districts of Sashima and Yūki320,150Hayato NakamuraInd.
Saitama Prefecture (16 districts) +DistrictAreas includedNumber of constituentsCurrent representativeParty representedMap1st districtSaitama, wards of Midori-ku, Minuma, and Urawa-ku387,753Hideki MuraiLDP2nd districtPart of city of Kawaguchi388,246Yoshitaka ShindōLDP3rd districtCities of Koshigaya and part of Kawaguchi380,633Hitoshi KikawadaLDP4th districtCities of Asaka, Niiza, Shiki, and Wakō391,025Yasushi HosakaLDP5th districtSaitama, wards of Chūō-ku, Kita-ku, Nishi-ku and Ōmiya-ku399,486Yutaka IharaLDP6th districtCities of Ageo, Kitamoto, Kōnosu, and Okegawa413,155Akihito ObanaLDP7th districtCities of Fujimi and Kawagoe388,446Hideyuki NakanoLDP8th districtCities of Fujimino, and Tokorozawa