The seat became vacant following the candidacy and election of its representative, Denny Tamaki to the governorship of Okinawa Prefecture. Tamaki was one of the two representatives from the Liberal Party in the House. He had served the district almost continuously since 2009 and defended the seat by a 17.56% margin in the 2017 election. The by-election was held on the same day with the second round of the unified local elections and another House by-election in the Osaka 12th district. The Okinawa-wide referendum in February influenced the by-election campaign.
The candidate supported by Tamaki and the All-Okinawa coalition, Tomohiro Yara won the by-election against LDP candidate and former minister Aiko Shimajiri.[2]
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