Wikipedia
Beonggeoji
A beonggeoji is a Korean hat worn by military officers in a low class or servants of yangban, aristocrats during the Joseon Dynasty. It is also called jeonnip or byeongnip. It began to be worn in the northwestern region of Korea and was spread to nationwide after Imjin Waeran (1592–1598) and Second Manchu invasion of Korea (1636) occurred.