is a single-member electoral district for the House of Representatives, the lower house of the National Diet of Japan located in western Yamanashi Prefecture. As of September 2022 it had 424,557 eligible voters.
Before the introduction of single-member districts in the 1990s, all of Yamanashi had formed one at-large district that elected five members to the House of Representatives. After the last House of Representatives election under the old system in 1993, Representatives from Yamanashi included Liberal Democrat Eiichi Nakao, Socialist Azuma Koshiishi and reformist Sakihito Ozawa. Nakao and Koshiishi contested the new 1st district in 1996: Nakao won. Koshiishi was elected to the Diet in the 1998 election to represent Yamanashi in the House of Councillors. In the 2000 Representatives election, Ozawa challenged Nakao and unseated him. He held onto the seat until 2012 when he joined the Japan Restoration Party and lost the district to Liberal Democratic newcomer Noriko Miyagawa, a former junior high school teacher.
Yamanashi lost one electoral constituency in reapportionment in 2013. Previously, the 1st district covered Kōfu, Enzan, Yamanashi City and Higashiyamanashi District. In September 2012, 218,115 voters were registered in the district, giving its voters one of the highest vote weights in the country.[1]
| Representative | Party | Dates | Notes | |||
|---|---|---|---|---|---|---|
| Eiichi Nakao | bgcolor= | LDP | 1996 – 2000 | |||
| Sakihito Ozawa | bgcolor= | DPJ | 2000 – 2012 | Joined Japan Restoration Party in 2012 Re-elected in the S. Kantō PR block | ||
| Noriko Miyagawa | bgcolor= | LDP | 2012 – 2014 | Re-elected in the S. Kantō PR block | ||
| Katsuhito Nakajima | bgcolor= | DPJ | 2014 – 2016 | |||
| bgcolor= | DP | 2016 – 2017 | ||||
| bgcolor= | Independent | 2017 – 2021 | Re-elected in the S. Kantō PR block | |||
| Shin'ichi Nakatani | bgcolor= | LDP | 2021 – | |||