Bone-rank system

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 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.

These criteria are described in detail in the 12th century Korean history Samguk Sagi, particularly its Monographs (ji 志), book 2 (ranks and offices).

"[7] The frustrated ambitions of the head rank six class in particular seem to have played a prominent role in the politics of the late Silla period.

The most prominent of the head rank six figures was undoubtedly Ch'oe Ch'i-wŏn, who following an illustrious career in China returned to Silla only to see his attempts at administrative reform rebuffed by an entrenched aristocracy.

In the early 10th century the nascent state of Goryeo, which succeeded Goguryeo, tapped into the head rank six intellectuals from Silla and Later Baekje to man its bureaucracy.