Akihiro Ota, deputy secretary general of New Komeito, retained his seat in Sunday's general election in the Tokyo No. 12 district, which had been a symbol of the ruling coalition's campaign cooperation.
Ota, 59, beat three other candidates, including postal rebel Eita Yashiro, 68, and Yukihisa Fujita, 55, of the Democratic Party of Japan.
Widely seen as a future leader of New Komeito, Ota will be serving his fifth term in the House of Representatives. He was first elected to the Lower House in 1993.
Ota said he was the only candidate in the district who supports Prime Minister Junichiro Koizumi's postal privatization bills.
The ruling Liberal Democratic Party, which Koizumi heads, did not field its own candidate in the district so it could support Ota and demonstrate cooperation between the two parties.
Yashiro, one of the 37 LDP members who voted against the postal bills in the Lower House in July, ran as an independent.
He said he had initially agreed not to run in the district because the LDP had promised him a spot on its proportional representation roster.
But when the deal came to light it drew fire from both within and outside the party, because it looked like he was getting special treatment.
