If Korea had a twin country, it would probably be Vietnam.

To start with, both countries are of a roughly similar size (220,000 sq.km for both Koreas and 310,000 sq.km for Vietnam) and have a similar population (76 million for both Koreas, 96 million for Vietnam).

Before the beginning of the Christian era, both experienced a massive inflow of Chinese culture. The Classical Chinese language (known as hanmun in Korean) became the dominant language of administration, high learning, and upper class literature from the very inception of their statehood.

Writing systems for the local vernaculars were eventually invented too, but,