Marquess Gaeseong (Korean: 개성후; Hanja: 開城侯; d. 1062), personal name Wang Gae (Korean: 왕개; Hanja: 王暟) was a Korean Royal Prince as the third and youngest son of Jeongjong of Goryeo and Queen Yongui.
[1] Due to his father's death when he was young, so he was raised and brought up into the Palace by his half-uncle, Munjong of Goryeo.
[2] In 1052, he became the preceptor in Dongsam Temple, Gaebu and appointed as Sangseoryeong (상서령)[3] to work in Sangju State with his new title as Marquess Gaeseong (개성후; 開城侯).
At the same time, he also received 2.000 sik-eup (식읍).
[5] He later died in 1062[6] and received his posthumous name Sinsang (신상; 愼殤).