Yamaguchi 1st district (山口[県第]1区, Yamaguchi[-ken dai-]ikku) is a single-member electoral district for the House of Representatives, the lower house of the National Diet of Japan. It is located in Yamaguchi and covers the prefectural capital Yamaguchi and the cities of Hōfu and Ube. In September 2023 the district had 388,682 eligible voters.[2] In 2012 they were 359,151.[3]
Before the electoral reform of the 1990s, the area had been part of the five-member Yamaguchi 2nd district which covered roughly the Eastern half of the prefecture and had been the former district of LDP presidents Nobusuke Kishi and Eisaku Satō. Another representative from the pre-reform 2nd district for the LDP was former four-term Tokuyama city mayor Sakahiko Kōmura. When Kōmura retired, his fourth son Masahiko won a seat in the district in 1980 and defended it in all pre-reform elections. After the electoral reform, Masahiko Kōmura took over the new single-member 1st district for the LDP. The main opposition NFP and the newly founded DPJ did not even nominate candidates in the first post-reform election of 1996, his only challengers were a Communist and an unaffiliated independent. In subsequent elections, the enlarged/"New" DPJ did nominate candidates; but Kōmura held onto the seat by large margins, even in the countrywide DPJ victory of 2009. The district remains – like two other of Yamaguchi's districts – an unbroken "conservative kingdom" (hoshu ōkoku). In the 2017 election Masahiko Kōmura retired, his eldest son Masahiro extended the streak with a two-thirds majority in his first election.
Kōmura was a minister in several cabinets in the 1990s and 2000s (Murayama, Obuchi, Mori II, Fukuda, Abe I). From 2000 to 2012, Kōmura led the Banchō Seisaku Kenkyūjo (previously Kōmoto faction, now Ōshima faction), one of the smaller, but well-established factions of the LDP that traces its roots to the centrist Reform Party and the pre-war Constitutional Democratic Party. In 2012, LDP president Shinzō Abe (Machimura faction, also from Yamaguchi) nominated him to succeed fellow faction member Tadamori Ōshima as vice president of the party.
^"衆議院小選挙区 - 確定投票状況" [House of Representatives election district - Fixed Vote Status]. Yamaguchi Prefecture Election Commission (in Japanese). 2017.
^"総務省｜令和4年9月1日現在選挙人名簿及び在外選挙人名簿登録者数" [Ministry of Internal Affairs and Communications - Number of registered voters as of 1 September 2023] (in Japanese). Retrieved 2024-12-07.
