Crown Prince Hyojang (Hangul: 효장세자; Hanja: 孝章世子; February 15, 1719 - November 16, 1728) is a member of the Joseon dynasty. His real name is Yi Haeng (Hangul: 이행; Hanja: 李緈). He is the first son of crown prince Yeongjo of Joseon.[1] He is the elder half-brother of Crown Prince Sado. He died when he was 9 years old. The cause is unknown.