() is a Korean term which was borrowed from the Chinese terms (; ; ) and (; ). The term () is a collective term which refers to historical official attire, which was bestowed by the government court, including Chinese courts of various dynasties. The () system was a court attire system in China which also formed part of the () system. This system was them spread to neighbouring countries and was adopted in Korea since ancient times in different periods through the ritual practice of bestowal of clothing. Acknowledgement through bestowed robes and crowns () from the Emperor of China, who held hegemony over East Asia, would give support to Korean Kings and successors, as being the authentic rulers of their country as well as confirmed the political status of the Korean kingdom in the rest of the Sinosphere. The system in Korea was different for each kingdom and changed throughout different periods. For example, initially given by the Chinese court in ritual practice, successive were more often than not locally manufactured in Korea with different colours and adopted into hanbok. The , which was used as the uniform of court officials (including civil court officials), formed part of the system and was used like the suit is nowadays.
History and development
Before adopting foreign systems, Korea had its own system based on indigenous , mostly rooted in indigenous ranking systems and state religion like Mu-ism. They favoured luxurious clothes like purple clothing for the top ranks and had decorative golden metal crowns and pointy hats called adorned with metal accessories and feathers. Silla and the other three kingdoms of Korea each had a version of the Bone-rank system where each social rank were allowed only certain clothes and certain ranks in court.
The rulers and the upper class in Korea's history adopted different kinds of foreign-influenced clothing in each dynasty, mostly from China's Tang, Song, Yuan, and Ming dynasties, while the commoners were generally less influenced by these foreign trends and their indigenous aesthetic continued to be seen in their clothing. Despite wearing foreign-influenced clothing, the rulers and the upper class still wore clothing that were indigenous outside of court. Under the dominance of the Han dynasty, Goguryeo and the little states () were bestowed attires and other miscellaneous items from the Han dynasty court. In the Goryeo dynasty, the system was largely influenced by the clothing system of other cultures, especially by the Han-Chinese ruled dynasties, the Mongolian Empire, the Khitan Liao dynasty (which adopted the ritual practice of bestowing from the Later Jin in the 10th century and later imitated the practice), and the Jurchen Jin dynasty. In Korea, whenever a new dynasty was established, the Korean ruler and his court would be bestowed official clothing from the Chinese emperor. This ritual of the Chinese Emperor bestowing official attire also included the official attire of the Korean Kings in the Goryeo and Joseon dynasties known as the Gonryongpo.
Goguryeo
After Gojoseon of Liaodong was defeated by the Han dynasty of China, four Chinese commanderies known as the Han-Sagoon were established in the region in 108 BCE. Proto-Koreanic entities were in constant conflict with these states until Goguryeo eventually ousted the Chinese from those regions by the early 4th century CE. One of them was the Daebang Commandery, established between 204 and 314 CE, and another was the Nakrang Commandery which continued to exist until the early fourth century CE and transmitted Han dynasty culture and lifestyle to the regions, including the Korean peninsula. Even after the ousting, Goguryeo court attire shows influences of the system.
A long type of po was introduced to Goguryeo and originated from the long which was worn by the Han Chinese in court.
Another form of robe was the mid-calf po, which originated from the Northern Chinese, and was used to fend against cold weather; this form of robe was adopted by the Goguryeo upper class for various ceremonies and rituals. This court po was eventually modified and became the with no vents. According to Samuel Lee: