The Liberal Democratic Party looked certain to win all three House of Representatives by-elections held Sunday, according to Kyodo News exit polls and analysis.
Amid extremely low voter turnout, LDP candidate Hiroshi Moriyama appeared set to win the Kagoshima No. 5 constituency seat, beating two opposition candidates.
Moriyama, 59, previously an LDP member of the House of Councilors, joined the race after giving up his Upper House seat.
The Lower House seat was left vacant by the death earlier this year of former LDP tax panel chief Sadanori Yamanaka.
In the Saitama No. 8 constituency, an LDP newcomer, 38-year-old lawyer Masahiko Shibayama, appeared likely to beat former Lower House member Atsushi Kinoshita, 59.
Kinoshita was fielded by the Democratic Party of Japan.
The seat was vacated by the resignation of Masanori Arai in January, following a vote-buying scandal involving the LDP politician and his local supporters in late 2003.
In the Hiroshima No. 5 constituency, former career-track bureaucrat Minoru Terada, 46, appeared set to claim another victory for the LDP.
His opponents were Mitsuo Mitani, 44, of the DPJ, and Susumu Matsumoto, 51, of the Japanese Communist Party.
The seat in the Hiroshima district was left vacant by the death earlier this year of former Foreign Minister Yukihiko Ikeda.
Voter turnout in Saitama stood at just 27.86 percent as of 7 p.m., down 16.8 percentage points from the Lower House general election in November.
Turnout stood at 39.54 percent in Hiroshima as of 5 p.m., down 9.06 points, and at 41.42 percent in Kagoshima as of 6 p.m., down 9.68 points, according to prefectural election commissions.