After the annexation of Korea by Japan in 1910, Son Byong-Hi, like essentially all Koreans, longed for independence. As a result of these years of oppression, Son helped to set up an underground anti-Japanese movement throughout 1918. This movement saw unprecedented cooperation between Chondo Kyo, Christians, and Buddhists as they united under a common cause. Son's Chondo Kyo gave financial support to the movement, and he insisted that the independence movement must be popular in nature and non-violent. A Declaration of Independence was prepared and 33 national leaders selected, including Son Byong-Hi.