Campaigns for the Saitama gubernatorial election and House of Councilors by-elections in three prefectures began Thursday as candidates registered for the polls.

The voting is scheduled for June 25, coinciding with the upcoming general election.

In the gubernatorial election, incumbent Yoshihiko Tsuchiya, Akio Takahashi and Morio Kato registered their candidacies.

Tsuchiya, 74, is backed by the ruling Liberal Democratic Party, New Komeito and eight other parties, while Takahashi, 72, is running with support from the Japanese Communist Party. Kato, 59, is not backed by any major party.

The election is expected to be a de facto vote of confidence in Tsuchiya, who is seeking a third term, although Takahashi is believed to have many supporters in the urban area.

The three by-elections — in Ishikawa, Mie and Ehime prefectures — are being held to fill vacancies created by the incumbents' decision to run in the general election for the House of Representatives.

Three candidates are running in each by-election.