Rock meets pansori. Blues meets gugak. Street dance meets a centuries-old shamanic ritual. That spirit of unlikely collaboration defines this year's Yeowoorak Festival, the National Theater of Korea's annual summer music festival, where traditional Korean music is paired with contemporary genres in an effort to blur the boundaries between them. "Pop music. Gugak. Those are just labels," said veteran folk-rock singer-songwriter Kang San-eh, who performed during the festival's opening weekend alon