The Supreme Court ruled on Wednesday that the House of Representatives election was constitutional after the introduction of the so-called Adams method of apportioning diet seats.
The method has faced strong opposition from both the ruling and opposition parties who claim that the number of elected representatives from regional areas will be reduced under the system. Some lawmakers are already working on electoral reform.
The Adams method is said to have been proposed by John Quincy Adams, the sixth U.S. president. The system allocates seats by emphasizing population ratios.
In lower house elections, the population of each prefecture will be divided by a certain figure, and the numerals following the decimal point will be rounded up to a whole number. The number of seats allocated to that prefecture will be determined by the result.
Prefectures with small populations will usually get two seats due to rounding up the decimal point.
The Supreme Court ruling on the day was a recognition of the legislature's efforts to date, said Toshimitsu Motegi, Liberal Democratic Party Secretary General Toshimitsu Motegi, who spoke to reporters at the party headquarters on Wednesday.
The next election will see further progress in correcting Votegi's vote value disparities, Motegi said. The Adams method will be used in the next election, and a 10 seat redistribution measure will be implemented, with 10 seats removed from 10 prefectures and a total of 10 seats added to five prefectures.
In November, a lower house committee adopted a supplementary resolution during the deliberations on the revised Public Election Law, which states that The Diet will conduct a review of the number of Diet seats and how electoral districts are divided. In December, six ruling and opposition parties said they would consider establishing a council for electoral reform.
However, feasible means have yet to be devised to increase the number of lawmakers in regional areas and achieve the vote value required by the Supreme Court. Kenta Izumi, chief of the main opposition Constitutional Democratic Party of Japan, said on Wednesday that the trend of increasing the number of seats in urban areas is problematic.
In response to the decision of the Supreme Court on Wednesday, dates for three supplementary elections have been set, with official campaigning beginning on April 11 and voting and ballot counting scheduled for April 23.
The three seats up for grabs are Yamaguchi Constituency No. The death of former Prime Minister Shinzo Abe, as well as Chiba Constituency No, has left 4 seats vacant in the lower house. 5 and Wakayama Constituency No.