Preliminary results of the 2010 census announced Feb. 25 show that in 97 of Japan's 300 single-seat Lower House constituencies, the vote-value disparity as compared with the least populated constituency has reached 2-to-1 or more, with a maximum disparity at 2.524-to-1. In the 2000 census, there were 95 such constituencies, with a maximum disparity at 2.573-to-1. This shows that reapportionment efforts made after the 2000 census have come to naught due to population movements.

An advisory body for the prime minister has begun reapportionment work for the Lower House. The basic idea is to hold the maximum vote disparity to 2-to-1 or less. If this principle is applied, Tokyo would get two more seats and Kanagawa and Aichi prefectures one more seat. Osaka, Tokushima, Kochi and Kagoshima prefectures would each lose a seat.

Constituencies may have to be newly demarcated since 92 municipalities are now each divided into more than one constituency — a result of the large-scale mergers of municipalities pushed by the Liberal Democratic Party-Komeito government. Although its work may become complicated, the council should do its best to ensure equality under the law as required by the Constitution.