As K-pop and K-drama go global, what are the secrets of their success? The Korean Wave - South Korea’s pop culture exports of music and TV dramas - has already swept across much of Asia, including the giant markets of China and Japan, bringing billions of dollars into the country’s economy every year. Now, with boy band BTS topping the US album charts, and hit dramas reaching streaming services around the world, the wave appears to be growing into a tsunami. How did this medium-sized Asian nation end up as the global entertainment industry’s biggest overachievers?