A bill to reapportion Upper House seats is likely to be enacted soon because the ruling Democratic Party of Japan and the leading opposition Liberal Democratic Party have agreed to support it.

In the latest Upper House election held in the summer of 2010, there was a maximum 5-to-1 disparity in the value of each vote between depopulated areas and populated urban areas.

Courts in various parts of Japan ruled that because of the disparity, the election was unconstitutional or was held in an unconstitutional state. The bill will reduce the maximum disparity to 4.75 to 1. But this is an ad hoc, minimum measure to avoid constitutional problems in the next Upper House election to be held in the summer of 2013.