<Tr> <Th> Revised Romanization </Th> <Td> Daehan Min - guk </Td> </Tr> <Tr> <Th> McCune--Reischauer </Th> <Td> Taehan Min'guk </Td> </Tr> <P> South Korea, officially the Republic of Korea (abbreviated ROK), is a sovereign state in East Asia, constituting the southern part of the Korean Peninsula . Officially, its territory consists of the whole Korean Peninsula and its adjacent islands, which are largely mountainous . South Koreans lead a distinctive urban lifestyle, as half of them live in high - rises concentrated in the Seoul Capital Area with 25 million residents . The capital Seoul is the world's sixth leading global city with the fifth largest economy and is the seventh most sustainable city in the world . </P> <P> The earliest neolithic Korean pottery dates to 8000 BC, with three kingdoms flourishing in the 1st century BC . The name Korea is derived from one of them, Goguryeo, which was one of the great powers in East Asia during its time, ruling most of the Korean Peninsula, Manchuria, some parts of the Russian Far East and Inner Mongolia, under Gwanggaeto the Great . Since the unification of the Korean kingdoms into Unified Silla and Balhae in the 7th century, Korea enjoyed over a millennium of relative tranquility under long - lasting dynasties . Koreans developed improved versions of many advanced innovations such as the metal movable type printing press, which used to print and publish the Jikji, the world's oldest extant movable metal type printed paper book in 1377 . In the 15th century, Koreans had one of the highest living standards in the world, and Sejong the Great invented Hangul to promote literacy amongst the general Korean population, enabling anyone to easily learn to read and write and transfer written information rather than spend years in learning complicated Hanja . Its rich and vibrant culture left 19 UNESCO Intangible Cultural Heritages of Humanity, the third largest in the world, along with 12 World Heritage Sites . </P>

Is the republic of korea known as north or south korea