Rigged Election of 15 March
A large-scale rigged election to make Lee Ki-poong vice president set off protests in Masan.

Bureau of Public Information - 공보처 홍보국 사진담당관 · Public domain · Source
In the presidential and vice-presidential election of 15 March 1960 the Liberal Party regime rigged the vote to elect Lee Ki-poong vice president — pre-stuffing 40% of the ballots, open voting in groups of three and five, and swapping ballot boxes. Students in Daegu had already protested on 28 February.
On election day protesters in Masan denounced the fraud and police opened fire. When the body of the student Kim Ju-yeol was found in Masan harbour on 11 April, protests spread nationwide into the April Revolution.