Bone-rank system

The bone-rank system (Korean: 골품제도) was the system of aristocratic rank used in the ancient Korean kingdom of Silla. It was used to segregate society, and particularly the layers of the aristocracy, on the basis of their hereditary proximity to the throne and the level of authority they were permitted to wield. The idea of royal blood in other societies is a close analogue to the idea of "sacred bone" in Silla thought.

Bone rank was strictly hereditary, and thus acted as a caste system. The scholar, Lee Ki-baik (1984, p. 43) considers it to have probably been adopted as part of the administrative law introduced from China and promulgated by King Beopheung in 520. However, this likely did nothing but institute in legal fact what was already a society segregated by bloodline and lineage. Although only two of the five known ranks were referred to as "bone" (골, 骨), the term "bone rank" has become widely used to describe the whole system.

A person's bone rank status governed not only official status and marriage rights, but also the color of one's garments and the maximum dimensions of one's dwelling and carriage. These criteria are described in detail in the 12th century Korean history Samguk Sagi, particularly its Monographs (ji 志), book 2 (ranks and offices). The Samguk Sagi's depiction of Silla life, however, has often been criticized for being excessively static. Unfortunately, since other sources are scarce, it is difficult to judge what sort of changes may have taken place in the bone rank system over the centuries.