Yun Bong-gil was born in Yesan County in the twilight years of the Korean Empire in June 1908. He attended Deoksan Elementary School and also studied in Ochi Seosuk (a village school that taught Korean and Chinese). As Korea had been made a protectorate within the Japanese empire in 1905, Yun grew up in a troubled country. Local resistance grew considerably with the annexation of Korea in 1910. It culminated in the March 1st Movement in 1919 that was aggressively crushed by the Japanese authorities (hundreds of protesters were massacred by the Japanese police force and army). The brutal repression that followed made many activists flee into China. In 1921, Yun began studying Mathematics.