Seiji Mataichi (又市 征治, Mataichi Seiji; 18 July 1944 – 18 September 2023) was a Japanese politician who served as a member of the House of Councillors. He was also the Chairman of the Social Democratic Party. Mataichi died on 18 September 2023, at the age of 79.
Source: “Seiji Mataichi”, English Wikipedia (CC BY-SA 4.0), excerpt