Yu In-seok (柳麟錫, 1842 – 1915) was a Confucian scholar, philosopher, and militia leader during the late Joseon Dynasty and the Korean Empire.
Born in Chuncheon, Gangwon Province, he was a disciple of renowned scholars such as Hwaseo Yi Hang-ro, Jungam Kim Pyeong-muk, and Seongjae Ryu Jung-gyo. Yu began his militia activities in 1864, and from 1895, he led nationwide resistance movements. After 1897, he traveled abroad, working to advance domestic military operations.
Yu was recognized as the head of the Hwaseo School and a key leader in the militia movements. In 1895, following the assassination of Queen Myeongseong and the implementation of the topknot-cutting order, he raised a militia and fought against government troops and Japanese forces in regions such as Chungju and Jecheon. Though his forces were defeated, he continued his resistance activities, moving between Manchuria and Liaodong, even attempting to secure military support from China.
In 1905, after the signing of the Eulsa Treaty, he once again organized a militia and led anti-Japanese campaigns. In 1908, he fled to the Russian Far East, where he collaborated with leaders like Yi Sang-seol and Choi Jae-hyeong to plan military operations in Korea, although these efforts ultimately failed. Even after Korea was annexed by Japan in 1910, Yu continued his fight for national sovereignty until his death in Manchuria. Yu strongly opposed Western ideas of equality and freedom, viewing them as sources of disorder and conflict, and emphasized maintaining traditional social order.
In recognition of his contributions, the South Korean government posthumously awarded him the Order of Merit for National Foundation (Presidential Medal) in 1962.
