고순옥 (Ko, Soon Ok)
Ko, Soon Ok (1937-2015) was a student directly below Sung, Keum Yun, having learned from Sung the old-fashioned way for decades. Ko was the official teacher & 후계자/이수자 for the Sung, Keum Yun school of kayagŭm playing; when kayagŭm players sought lessons from Sung, who would be busy performing and touring, Ko would teach them, in place of the intangible asset. Since then, she has retired from her teaching career in Korea to Los Angeles, to live near her family. Currently, only Sung's eldest daughter and Ko, Soon Ok are qualified to teach Sung's masterpiece, ‘눈물이 진주라면’ (If Tears were Pearls).