Chŏngju Yu clan
The Chŏngju Yu clan ( is a Korean clan. Their bon-gwan is Chŏngju, in  modern-day Kaepung, Kaesong. It was founded by Yu Chon-gung who was a nobleman from Chŏngju and served as one of the Three Major Grand Masters (태위 삼중대광, 太尉 三重大匡). History
Wang Kon first met the future Queen Sinhye in Chŏngju while he was still serving under Taebong's monarch, Kung Ye. When four of Kung Ye's generals suggested Wang to rebel against Gung, Queen Sinhye's family, actively persuaded Wang to overthrew Kung Ye. A prominent ancestor (jungsijo) who made the family prosperous was Yu So (유소, 柳韶) become a Jeonjungsieosa (전중시어사, 殿中侍御史) in 1011, Eosajapdan (어사잡단, 御史雜端) in 1016, Saheonjungseung (사헌중승, 司憲中丞) in 1019, and Ganuidaebu (간의대부, 諫議大夫) in 1022, also Taejabingaek (태자빈객, 太子賓客). Goryeo Queen Consorts

Agnatic descent
Chŏngju Yu produced the three-queens consorts of Goryeo, they were:
Queen Sinhye, King Taejo's first wife. Queen Jeongdeok, King Taejo's sixth wife
Queen Myeongui, King Sukjong's only wife. Adopted Chŏngju Yu clan
Queen Munhye, King Munwon's only wife. Queen Seonui, King Daejong's only wife. See also
Yoo (Korean surname)

References

Chŏngju Yu clan
Clans based in Kaesong