As voters head to the first round of the unified nationwide local elections Sunday, a lack of candidates in the prefectural and municipal assembly races means incumbents in many districts are running unopposed.

But in Osaka, the elections are merely a prelude to a much-anticipated May referendum on the future of the city, and interest is high as all electoral districts have multiple candidates.

Nationwide, about 22 percent of the seats in 41 prefectural assembly races will be uncontested, leading some Tokyo media and pundits to dismiss the elections as unimportant and having little impact on national policy.

However, with Osaka voters due to go to the ballot box again on May 17 to vote on a referendum on whether to break up the city of Osaka's 24 wards into five semiautonomous districts, Sunday's elections have become a battle between Osaka Mayor Toru Hashimoto, who is leading the merger, and the established political parties, whose local chapters are against such a plan.

Hashimoto's Osaka Ishin no Kai (One Osaka) has a plurality of seats in both the municipal and prefectural assemblies, but has worked with Komeito, whose local chapter opposes the merger, to form a majority in both chambers. In the 88-seat prefectural assembly, Osaka Ishin is fielding 53 candidates, while 38 Osaka Ishin candidates are standing for election in the 86-seat municipal assembly.

Komeito will field only 15 candidates for the prefectural assembly poll and 20 for the city assembly election. The party opposes the merger.

The Liberal Democratic Party will field 42 candidates in the prefectural election and 23 in the municipal election. The party's Osaka chapter has traditionally worked closely with Komeito and also opposes the merger. But even with the continued strength of the LDP at the national level, it's unclear how voters will view the Osaka LDP chapter's candidates.

On the other hand, Osaka Ishin now faces a possible backlash over a scandal involving Lower House Diet member Sayuri Uenishi, who was just expelled from Ishin no To (Japan Innovation Party), of which Osaka Ishin is its local affiliate. She was kicked out of both parties after admitting to skipping a vote on the fiscal year budget due to health reasons, but had, in fact, dined out at a restaurant the night before the budget vote.

Hashimoto called for her resignation. Uenishi has refused to do so and said she will continue as a non-affiliated member.