The Mainichi Shimbun projected on July 13 the “gap in the value of a vote” in the two Diet houses based on a residents’ basic register (as of Jan. 1) issued by the Ministry of Internal Affairs and Communications. In the House of Representatives single-seat constituencies, the maximum disparity in vote values stood at 2.148 between the Hyogo No. 6 district, which has the largest population (588,992), and the Miyagi No. 5 district, the smallest population (274,219). The vote-value disparity exceeded two-fold in 22 districts of the 295 nationwide.
In the Upper House election, the vote-value gap between the most populous Saitama constituency (1,197,815) and the least populated Fukui constituency (393,627) stood at 3.043.
The Supreme Court ruled in November 2014 that the 2013 Upper House election, which reached a maximum 4.77 to 1, was “unconstitutional.” Following the ruling, the Diet narrowed the vote-value gap by adding 10 seats in some constituencies and dropping 10 in others, including the mergers of the constituencies of Tottori and Saitama and those of Kochi and Tokushima. As a result, the largest gap was decreased to 2.97-fold (based on the 2010 national census). Based on a population survey, the largest gap drastically dropped from 4.78 to 2.0.
However, the maximum vote disparity topped again threefold in the latest Upper House race. Also in an estimate based on the number of electoral roll registrant (voters) on June 21 ahead of the election, the vote-value disparity between the Saitama and Fukui constituencies was 3.08 to 1. As groups of lawyers have filed suits claiming that the results of the election are invalid, there is a possibility that the judiciary will seek drastic reform before the 2019 Upper House election.