Yi Chahà Âng (born 1305), posthumously known as Grand Prince Wanchang, was a late Goryeo period second rank official () who became part of the early Joseon royal family member as the first and oldest son of Yi Ch'un, making him uncle to Yi Sà Âng-gye, its founder.
He studied under the tutelage of U T'ak as one of his students. Yi served the Yuan dynasty as a chiliarch (). After his nephew, Yi Sà Âng-gye () established the new dynasty, Yi Chahà Âng was posthumously given the office of the minister of military affairs () and on 9 March 1871, Yi was given the posthumous name Chà Ânggan (). In 1872, Emperor Gojong of Korea gave him a posthumous name as Grand Prince Wanch'ang () and was enshrined in Yà Ângjongjà Ânggyà Âng () alongside his parents. Their tomb located at Gwiju-dong, Hamheung.