In 1918, Han published "Whole Mind" ("Yusim"), a work that aimed to enlighten young people. In the following year, he played an important role in the 3.1 Independence movement with Chae Lin, for which he was later imprisoned and served a three-year sentence. During his imprisonment, Han composed "Reasons for Korean Independence" ("Joseondoglib-i-yuseo") as a response to the official investigation into his political engagement. He was later acquitted in 1922, at which time he began a nationwide lecture tour. The purpose of the tour was to engage and inspire youth, an objective first established in Han's "Whole Mind". In 1924, he became the Chair of the Buddhist youth assembly.