Vote-value disparities have widened further in both houses of the Diet, according to data released by the internal affairs ministry.
Regarding the Lower House, the disparity between the most heavily populated constituency, Chiba No. 4, and the least crowded district, Kochi No. 3, stood at 2.482 as of March 31, up from 2.442 a year earlier, according to the basic residence registry.
The population in the Chiba No. 4 district increased by 1,675 from a year earlier to 602,996, while that in the Kochi No. 3 constituency declined by 3,302 to 242,976 — the lowest figure for the seventh year in a row.
The vote-value gap topped 2.0 for the first time in Kochi No. 3 and 11 other districts, including Tokyo No. 20 and Miyagi No. 1, raising the number of constituencies with such a disparity to 84.
The Supreme Court ruled in March 2011 that vote-value disparities of up to 2.3 in the 2009 general election for the House of Representatives were in “a state of unconstitutionality.”
To rectify the situation, the ruling Democratic Party of Japan has submitted a bill to trim five Lower House constituencies and cut 40 proportionate representation seats. The Liberal Democratic Party has submitted its own bill calling for five constituencies to be reduced in size.
The largest vote-value disparity for the Upper House was the 5.049 recorded between Kanagawa and Tottori prefectures, up from 5.013 a year earlier, the resident register data showed.
Some high courts ruled that a 5 to 1 disparity in constituencies in the 2010 House of Councilors election was unconstitutional.