The Hiroshima High Court ruled Thursday that the outcome of the July Upper House election in Okayama Prefecture should be invalidated due to an unconstitutional disparity in the weight of votes.

The decision by the court’s Okayama branch is the first among 14 similar lawsuits filed with high courts across Japan by groups of lawyers who argue that the disparity of as much as 4.77-fold in the nationwide July 21 Upper House election violates the equal-protection clause in the Constitution.

The Supreme Court ruled in October 2012 that the maximum fivefold disparity in the weight of votes in 2010 left that year’s Upper House election “in a state of unconstitutionality.”

As a result of amendments to the election law last November, the disparity in the number of eligible voters per Upper House member came to 4.77-fold between Tottori, which has the least voters, and Hokkaido, which has the most.

Between Tottori and Okayama, the difference stood at 3.27-fold.

During the trial at the Okayama court, the lawyers seeking the invalidation argued it was unconstitutional to hold the election before Upper House seats could be reapportioned to reflect district populations.

The defendant — the Okayama prefectural election board — countered that the disparity had at least been reduced and that it did not have enough time for drastic reform in the nine months between the Supreme Court ruling and the election.

Article 14 of the Constitution stipulates all people are equal under the law.

The revised election law says in a supplementary provision that deliberations to fundamentally reform the election system should be concluded before the Upper House election in 2016.

Lawsuits have also been filed to invalidate races with vote-value disparities of up to 2.43 times in the Lower House election of last December, when the Liberal Democratic Party returned to power.

Ruling on one of the Lower House suits, presiding Judge Noriyoshi Katano at the Okayama branch invalidated the election outcome in the Okayama No. 2 district.

On Nov. 20, the Supreme Court ruled the vote disparities in the Lower House election were “in a state of unconstitutionality,” while stopping short of declaring the election outcome outright violated the Constitution and should be invalidated.