Koreans did see themselves as distinct from the Chinese even prior to the rapid and relatively recent rise of nationalistic sentiments. After all, why would they not have seen themselves as distinct from the Chinese? Korea has never been fully under direct Chinese rule, although the various states in the peninsula have historically been tributaries of China. The Neo-Confucian Joseon elite saw themselves as fully civilized, like the Chinese, and perhaps more civilized than China itself after the latter fell under Qing rule. But they still realized that they were different from the Chinese.

There are occasional self-references of Koreans as barbarians or foreigners (夷 yi). For instance, in 1393 Taejo explains one reason why he chose not to invade Ming China some years before: because barbarians [夷] should not disorder China [華]. The famous Lament for the Righteous Emperor by Kim Jongjik also states that "King Huai is a person from southern Chu (namchu) and I am an eastern barbarian (dongyi)." The Chinese themselves were much more prone to referring to Koreans as "eastern barbarians." The Nanjing's Ministry of Rites naming Korea's new dynasty in 1393 says, for example, that "as a name for the Eastern Barbarians solely the word "Joseon" [Mandarin Chaoxian] is beautiful."

Korean texts also distinguish "the Chinese people" (漢人, 唐人) from both Korean people and Chinese civilization. A government report in 1625 discussing how the "Han Chinese" (漢人) have taken to thieving, raping and killing wouldn't make much sense if Koreans considered themselves Han Chinese, for example. The same year (the 1620s are full of stories of Chinese pirates in Korea, because a warlord named Mao Wenlong set himself up off the Korean coast and began pillaging the coastline) there is another story of how "the Han Chinese" have forced Koreans to flee to the mountains as a result of their pillaging and raping. A 1566 entry in the Annals (or Veritable Records) of the Joseon Dynasty states that "the Chinese" now scorned Korean envoys to Beijing as a result of the latter's disreputable actions.

I've only skimmed the surface here, but recorded evidence is quite clear on the fact that Koreans and Chinese were considered distinct;