Tokyo 18th District (東京都第18区, Tōkyō-tō dai-jūhachi-ku, or 東京18区 Tōkyō jūhachi-ku) is a constituency of the
House of Representatives in the
Diet of Japan. It is located in
Western Tokyo and consists of the cities of
Musashino,
Koganei and
Fuchū. Until 2002, it included
Mitaka (now part of
Tokyo 22nd district) instead of Fuchū. As of 2016, 436,338 eligible voters were registered in the district.[2]
From its creation to 2012, the district was represented by former
Prime Minister and popular
Democratic Party co-founder
Naoto Kan. In the
election of 2005 it was the only constituency the opposition could defend in Tokyo against the landslide for
Junichiro Koizumi's ruling coalition. In 2003, then party chairman Kan beat former Minister of Labour
Kunio Hatoyama, the younger brother of Democratic Party leader
Yukio Hatoyama by a margin of more than 50,000 votes.
In the
election of 2009,
Masatada Tsuchiya was the candidate for the ruling
LDP.[3] Tsuchiya who failed to unseat Kan in 2005 was a representative for the Tokyo proportional representation block where he ranked second on the LDP's list 2005.[4] In 2009 he failed to secure reelection in the Tokyo block. Kan was elected president of the then ruling Democratic Party again in 2010 shortly before the 2010 House of Councillors election; but his cabinet resigned after only 15 months. In the 2012 House of Representatives election, Kan lost Tokyo 18th district to Masatada Tsuchiya by more than 10,000 votes; ranking third on the Democratic proportional list in Tokyo (sekihairitsu 87.9%), he gained the last of the three Democratic seats in the Tokyo proportional block behind
Banri Kaieda and
Jin Matsubara.[5]
Kan joined
the Constitutional Democratic Party of Japan before the 2017 general election and regained the seat. Tsuchiya lost his seat even with his high sekihairitsu as he did not run for the proportional block. In 2021 Kan was challenged by a former
DPJ lawmaker,
Akihisa Nagashima, who had joined the
LDP. Kan managed to hold his seat in a tight race that received national attention.[6][7]