The ruling Liberal Democratic Party has fashioned a proposal to revise the Upper House election system to reduce vote-value disparity while also ensuring that all 47 prefectures have at least one member in the chamber.

Currently, the prefectures of Kochi and Tokushima in Shikoku, as well as Tottori and Shimane in western Japan, are combined into a single prefectural electoral district. That measure was taken to avoid having vote disparity widen with more populous urban prefectures.

Under the LDP plan, the combined prefectural single-member district would remain, meaning that one prefecture would not have an individual in its jurisdiction representing it in the Upper House through the prefectural district.

To address that absence, a slight twist would be made to the proportional representation constituency that is the other major component of the Upper House election system.

In the proportional representation constituency, voters can write in either candidate names or party names. Seats are distributed according to the combined votes received by a political party, with individual seats awarded based on the number of votes tallied by each individual candidate.

Under the LDP proposal, a new candidate roster will be introduced that ranks the individual candidates and seats to be awarded based on that ranking.

To ensure that all 47 prefectures have an Upper House member from their jurisdiction, the LDP plan calls for listing high on the roster candidates from the prefecture not running in the prefectural district constituency.

Along with introducing the new candidate roster, four seats would be added to the proportional representation constituency. In each of the Upper House elections held every three years, two of those seats would be contested, meaning that candidates could be placed on that roster from the prefecture of the two combined districts without a candidate in the prefectural district constituency.

In another move to address vote disparity, Saitama Prefecture would be given two additional seats, meaning that in each Upper House election it would have four seats up for grabs from the current three.

Saitama Prefecture now has the most voters per Upper House member in the prefectural district constituency so adding one additional seat would reduce the vote-value disparity with the least populous prefecture to under three.

With an Upper House election scheduled for the summer of 2019, the LDP is seeking to pass legislation to revise the Public Offices Election Law in the current Diet session to allow for sufficient time to inform the public about the changes.

Along with submitting the proposal to other political parties on June 1, the LDP is also seeking to extend the Diet session to ensure passage of the bill.