The First Hallyu Wave
Winter Sonata aired in Korea in 2002, and in Japan it ran first on NHK's satellite channel from April 2003. It came down to terrestrial broadcast the following April, in 2004. That order says something about the character of this wave — it reached the people who went looking for it first, and only once their number grew did it arrive in the living room.
Where the word Hallyu came from is not clear. One account has it appearing first in a Chinese newspaper on 19 November 1999; it is also said that Chinese-language media in mainland China and Taiwan began using it earlier. This map leaves the accounts standing as they are.
On the institutional side there is a record. In Korea, an agency for promoting cultural content was set up in August 2001, became a corporation under statute in October 2002, and in May 2009 five bodies were merged into the Korea Creative Content Agency. Over the twenty years it took this wave to reach the top of the world (→ K-Drama Goes Global), the structures supporting it were being rebuilt as well.