This study is a review of Ipsik, the decorative ornaments found on traditional Korean horsehair hats, known as Ipja, which were worn by men in the late Joseon Dynasty. In a broad sense, Ipsik are regarded as men's accessories. Therefore, although this study is limited to Ipja, it is significant in the sense that it delves into one facet of men's accessories in detail. Because the appearance of the horsehair hats was rather mundane, Ipsik and Ibyeong were added as ornaments. During the Joseon period, various types of hat ornaments existed, named Maeksu, Hosu, Gongjagu, Sangmo, Jingdori, Ijeon, Guyeongja and Ibyeong. A person's social ranking and class could be discerned by the materials used in the Ipsik he wore. Jeongja, a decorative accessory used to attach to an official's hat, was institutionalized in the sixteenth year of King Gongmin's reign(1367), during the Goryeo Dynasty, prior to the founding of China's Ming Dynasty in 1368, which indicates that Jeongja were influenced by the Yuan Dynasty. A record in Lao Chi'ta (a textbook of spoken Chinese estimated circa 1346) confirms this fact. Based on a review of literature, we learn that just as with Ongno, Jeongja were imported for use on Jeonrip, a soldier's hat. During the Ching Dynasty, Jeongja were further subdivided and more exquisitely designed. On the other hand, in the Joseon Dynasty, a rule was handed down mandating that a royal prince use gold for his jeongja, officials at third rank or above use silver, and governors, commanders in chief, and officials with the Office of Inspector General and Office of Censor General use jade. Inspectors were permitted to use crystal. Jeongja made of jade were used until the late Joseon Dynasty.