Examined in this article is how the recognition of Sam-Han (三韓), which was the foundation of a notion (developed by the Shilla people) that suggested the Three Han entities had been one all along (三韓一統意識), originated and formed. Also examined is how Shilla viewed the other opponent countries during the Unification war.
The term Sam-Han (三韓), appearing in Chinese historical texts, originally referred to the three Han entities on the Korean peninsula. Yet later, when all of these entities disappeared, it became a term used to refer to all the historical entities existing in the east of China in a generic sense, including Goguryeo (高句 麗), which was not part of the Sam-Han legacy, as well as Joseon (朝鮮), which had existed well before the time of Sam-Han.
Diplomatically, the Chinese Dang (唐) dynasty encouraged the three dynasties to get along with each other, and emphasized historical similarities shared by them (supposedly through Sam-Han), but Shilla never accepted or embraced such a notion. There are examples in Samguk Yusa (Tales of the Three Dynasties that Remain to be Told) or Samguk Sagi (History of the Three Dynasties), in which the Shilla people are depicted as referring to their own history as the history of Sam-Han, but in most cases they were rather expressions came from their descendants, the people of Goryeo.
Being continuously harassed by all types of foreign invasions, Shilla needed an ideological notion that could enable itself to sustain and endure; hence, the Shilla people came to consider themselves as occupying the center of the universe. One expression revealing this type of view of the world was Gu-Han (九韓, nine Han entities), which was based upon the concept of Nine Types of Yet-to-be Civilized ( Gu-Ih , 九夷). In theory, these Gu-Han units paid tribute to Shilla and were therefore conceptual figures essentially different from the Sam-Han units, which included Shilla itself.