YAMAGUCHI – Official campaigning for the April 28 Upper House by-election in Yamaguchi Prefecture began Thursday, with former Justice Minister Hideo Hiraoka, backed by the Democratic Party of Japan, challenging a newcomer from the Liberal Democratic Party.

The House of Councilors by-election will be the first Diet election since the LDP regained power from the DPJ in the December general election, making it the first national-level electoral test for Prime Minister Shinzo Abe, whose electoral base is in Yamaguchi.

Expected to be a fight between Hiraoka, 59, who lost his House of Representatives seat in the December election, and the LDP’s Kiyoshi Ejima, a former Shimonoseki mayor, the race will be closely watched as a prelude to the Upper House poll scheduled for July.

Ejima, 56, is also endorsed by the LDP’s coalition partner, New Komeito, while Hiraoka, who is running on an independent ticket, is also backed by the Midori no Kaze (Green Wind) parliamentary group and the Social Democratic Party.

The LDP, led by Abe, is pulling out all the stops to win the election, which would give the LDP and New Komeito a boost in their aim to secure a majority in the summer poll.

“I am convinced that Japan will become stable if the Abe administration continues,” Ejima said in his first public speech after filing his candidacy in front of about 1,000 supporters at a park in the city of Yamaguchi.

LDP Vice President Masahiko Komura, a Lower House member also from a constituency in Yamaguchi, was one of the party members who came to show his support for Ejima.

The DPJ, plagued by the departures of members looking to run in the Upper House election, is seeking to use the Yamaguchi by-election to turn the tide.

Hiraoka, speaking in front of about 300 people, vowed to gather political forces that can connect with the people. DPJ President Banri Kaieda and SDP leader Mizuho Fukushima came to cheer him on.

Hiraoka opposes the construction of a new nuclear plant in the town of Kaminoseki, one of the key election issues.

Two other candidates — Naoko Fujii, 60, a former assembly member of the city of Shunan who is with the Japanese Communist Party, and Miwako Kawai, a 50-year-old member of the Happiness Realization Party — are also running in the poll.

Fujii expressed her opposition to building the nuclear plant in Kaminoseki, saying, “Kaminoseki must not turn into another Fukushima.”