Seungsahn, South Korean spiritual leader, founded the Kwan Um School of Zen (b. 1927)
Seungsahn Haengwon (Korean: 숭산행원대선사; Hanja: 崇山行願大禪師; RR: Sungsan Haeng'weon Daeseonsa, August 1, 1927 – November 30, 2004), born Duk-In Lee, was a Korean Seon master of the Jogye Order and founder of the international Kwan Um School of Zen. He was the seventy-eighth Patriarch in his lineage. As one of the early Korean Zen masters to settle in the United States, he opened many temples and practice groups across the globe. He was known for his charismatic style and direct presentation of Zen, which was well tailored for the Western audience.

Known by students for his many correspondences with them through letters, his utilization of dharma combat and expressions such as "only don't know" or "only go straight" in teachings, he was conferred the honorific title of Dae Jong Sa in June 2004 by the Jogye Order for a lifetime of achievements. Considered the highest honor to have bestowed upon one in the order, the title translates "Great Lineage Master" and was bestowed for his establishment of the World Wide Kwan Um School of Zen. He died in November that year at Hwagaesa in Seoul, South Korea, at age 77.