This study is concerned with the jang il (　日). The purpose of this study was to trace the origin of jang il and to identify forms and the meaning of it. Significant findings and results of this research can be summerized as follows : It was found that jang il was a kind of brimmed hat with a round crown. People of Han Dynasty period wore jang il. It was favored by the people of Wei Chin (魏晉) Dynasty period of China and was a very popular hat in these periods. It was used by farmers and merchants. It was found that jang il was worn by a tribe of Kang(羌) in prehistorical period. It is considered that jang il of the Chinese, was derived from the people of Kang(羌). In the Tang and Five Dynasty periods women also wore jang il. Women from the upper class appeared used jang il. It appeared that Koguryoreans also used jang il : it was a kind of black wide brimmed hat with a round crown. which can be found in the tomb paintings of Yong Kang(龍崗). A horse rider wears jang il.