The by-election was triggered by the death of the sitting member, former Speaker of the House and Foreign Minister Nobutaka Machimura from cerebral infarction in Osaka on 1 June 2015.

[5] The ruling LDP nominated Yoshiaki Wada, a former businessman and the son-in-law of Machimura, to contest the election; it was his first time running for public office.

[6] Opinion polls prior to the election showed that voters were primarily concerned with foreign policy and security issues, followed by welfare and childcare.

[2] Wada campaigned strongly on his position as a successor to his father-in-law Machimura, whilst also providing his twenty years of experience in a trading company as evidence of his ability to improve economic conditions and promote the export of Hokkaido's agricultural produce.

Wada described the campaign as a tough battle, focusing on improving the local economy and becoming a "salesman" for Hokkaido in his victory speech.