Yu Ch'ŏn-gung (Korean: 유천궁; Hanja: 柳兢達) or also known as Local Chief Yu (유장자; 柳匠子)[2] was a rich-nobleman of the Later Three Kingdoms period[3] who became the father of Queen Sinhye and father in-law of Wang Kon, Goryeo's founder.
[citation needed] During Jinseong of Silla's reign, Yu Ch'ŏn-gung was a nobleman from Paseo region (along with Wang Ryung from Songak, Pak Chi-yun from Pyeongju, Hwangbo Che-gong from Hwangju, etc.)
[3] Although the local lords of the Paseo region were independent from Kung Ye, they finally surrendered to him and Wang's son, Wang Kon, became Kung Ye's general and took over the western coast (including Ganghwa Island.
Yu actively provided ship technology and knowledge acquired through maritime trade to Wang.
Yu's domain of Jeongju Port became an outpost where Wang's naval forces could build ships and train to conquer Geumseong (Naju) in Later Baekje.