121 (of the 242) seats in the House of Councillors
Leader	Banri Kaieda	Shinzō Abe
Party	Democratic	Liberal Democratic
Last election	106 seats 39.0% (prefectural) 31.6% (proportional)	84 seats 33.4% (prefectural) 24.1% (proportional)
Current seats	85	84
Seats needed	16	38

Single-member districts

Single-member districts for the House of Councillors often play a crucial role for the overall outcome of a regular election as they can be swung completely with relatively little change in popular vote whereas the SNTV multi-member districts and the proportional seats are usually shared between ruling camp and opposition. In the 2007 Councillors election, the single-member districts were won by 6 members from the then ruling Liberal Democratic Party (LDP) and 23 members of the DPJ-led opposition. In 2010, the LDP picked up seven seats in single-member districts.

Incumbents, party affiliations and some already declared candidates are:

 Opinion polling for proportional seats

In the run up to the election, various organizations are conducting opinion polls to gauge voting intentions for the available proportional seats. Polls are listed in chronological order, showing the oldest first.
Date Institute        
LDP DPJ JRP NKP YP PLP JCP U/O
9-10 March TBS/JNN 37.5% 8.1% 3.6% 2.2% 2.7% - 2.2% 43.7%
23-24 March Fuji News Network 41.8% 5.3% 9.6% - 4.7% - - -
April Kyodo News 48.2% 6.7% 10.4% 3.9% 4.5% 0.5% 3.2% 22.6%
18-19 May Kyodo News 44.4% 6.8% 5.7% 4.4% 5.2% 0.3% 3.1% 30.1%
1-2 June Kyodo News 44.6% 7.9% 4.5% 6.4% 4.0% 0.3% 2.6% 29.7%