Ryu, Gwan-Sun (march 15, 1902 – October 12, 1920) was a student and organizer in what would come to be known as the March 1st Movement against the Japanese colonial rule of Korea in South Chungcheong. In 1919, Yu, Kwan-Sun was a student at Ewha Womans University's high school in Seoul, where she witnessed the beginnings of the March 1st Movement. Her deep faith in God and the teachings from the Methodist Ehwa School gave her the courage to act boldly. When the school went into recess, following an order by the Japanese government closing all Korean schools, she returned to her home in Jiryeong-ri (now Yongdu-ri).
There, along with her family, she began to arouse public feeling against the Japanese occupation. She also planned a demonstration for independence, which included people from some neighboring towns, Yeongi, Chungju, and Jincheon. The demonstration was scheduled to start on the first lunar day of March 1919 at 9:00 a.m. in Awunae Marketplace. About 2,000 demonstrators shouted, "Long live Korean Independence!" ("대한독립만세"). The Japanese police were dispatched at around 1:00 p.m. that same day, and Yu was arrested with other demonstrators.