Prime Minister Yukio Hatoyama's Democratic Party of Japan aims to win an overall majority in the Upper House in this summer's election, solidifying the DPJ's hold on the Diet following its landslide victory in the 2009 Lower House race.

The DPJ currently only has a majority in the Upper House with the support of its two small coalition partners — Kokumin Shinto (People's New Party) and the Social Democratic Party. The main opposition force, the Liberal Democratic Party, which lost power in the August election, is hoping to stage a comeback by ensuring the coalition parties lose their combined majority.

As of now, 197 people are preparing to run in July, either in districts or the proportional representation segment of the election. The figure is about 30 fewer than around the same time ahead of the 2007 Upper House election.