Former Social Democratic Party leader Takako Doi failed to retain her House of Representatives seat for a 13th term in Sunday's election, bringing a 36-year Diet run to an end.

Doi, 76, also a former Lower House speaker and staunch advocate of the war-renouncing Constitution, refrained from running in her single-seat district in Hyogo Prefecture and was ranked last on the SDP's five-candidate list for the proportional representation segment in the Kinki block.

By putting herself at the bottom of the list, Doi was apparently aiming to expand the SDP's overall support base and help more junior members win a seat, including disgraced former SDP lawmaker Kiyomi Tsujimoto, 45, who was convicted of defrauding the government.