Seoulites will vote in a new superintendent of education in by-elections set for mid-October, while four administrative districts across the nation will choose mayors.

The “mini” by-elections, set for October 16, will fill the posts of superintendent at the Seoul Metropolitan Office of Education and mayoral posts in Geumjeong district in Busan, Ganghwa County in Incheon, and the counties of Yeonggwang and Gokseong in South Jeolla Province. 

The ruling and opposition parties are expected to wage aggressive campaigns in this election, the first since the two parties appointed new leaders. 

The interior ministry said Monday that it will accept applications from Tuesday to Saturday for voting by mail. 

Those who want to vote by mail should mail their applications, or submit them in person, to the appropriate city or district office or local community center by 6 p.m. Saturday. 

Candidate registration runs Thursday and Friday, and early voting will take place October 11 and 12.