[2] On 17 September 2010, Mabuchi was named as the new minister of land, infrastructure, transport and tourism in the reshuffled Naoto Kan cabinet.

[5] Mabuchi left prime minister Kan's cabinet on 14 January 2011,[6] after the then-opposition Liberal Democratic Party (LDP) passed a censure motion against him following the leaking of Japanese Coast Guard footage of the 2010 Senkaku boat collision incident.

[4] After the Democratic Party of Japan suffered a major defeat to the LDP under Noda at 2012 Japanese general election.

[11] Mabuchi returned to the House in February 2019 after the resignation of Shinji Tarutoko, who was contesting the Osaka 12th district by-election.

Being the candidate with the next largest sekihairitsu in Kibō no Tō's 2017 Kinki proportional representation list, Mabuchi was next in line to fill Tarutoko's PR seat.