Kok-Ryung covers the collar of underwear and protects the neck. It is between outer garment and underwear and its form is bent. According to literature, Cheom-Yu, Keup, and Pang-Ryung belong to Kok-Ryung. Kok­Ryung was used in Yemaek and also it was used as a part of the uniform of government officer in Song Dynasty. The results of the study were as follows: 1) With the changes of the times, Cheom-Yu was used in Ju Dynasty, Pang-Ryung was used in Han Dynasty, and Kok-Ryung was used from Nam-Jo through Soo, Tang, Song Dynasity. 2) Cheom-yu, Pang-Ryung, and Kok-Ryung were all made of long rectangular cloth. How­ever, Chemo-Yu and Pang-Ryung were adjusted in front of the neck, Kok-Ryung was adjusted on the back. 3) The purpose of Kok-Ryung was practial one of sweat clothes at first. But it became for decoration and dignity gradually. Therefore, the users of it were changed from the common people to high government officers. 4) Cheom-Yu, Po-Ryung, Keup, and Pang-Ryung were all a kind of scarf and they are the same with Kok-Ryung in the respect. They were put on between outer garment and underwear or attached under the collar of outer garment. 5) Kok-Ryung of Song-Sa seems to be the round collar the uniform of government officers and it is different from Kok-Ryung of Suk-Myung.