Less than a dozen years ago, Japanese pop music-J-Pop-dominated Asia. Today, K-pop-the South Korean product recently made famous in America by Psy's viral "Gangnam Style" video-is poised for world domination, with Asia already in its pocket.

A Korean producer, m-flo's Taku Takahashi, cuttingly summarized the flipping of the script when he recently tweeted, "fuck JPOP 2012." Just how did J-pop crater, and K-pop purloin its destiny as the world's most cosmopolitan music?

Japan was (and remains) the second biggest music market in the world, with an enormously pervasive pop culture in general. But what was more important than its built-in audience was J-pop's ambition. Fueled by such success stories as singer Hikaru Utada (pictured below), who at age 16 wrote and recorded the biggest selling album in Japanese history, and producer Tetsuya Komuro, whose golden touch generated a steady stream chart-topping singles for Namie Amuro, TRF, Globe and others, in the '90s Japanese music companies began to expand into Taiwan, Hong Kong and Malaysia.

Nowhere, though, was their impact greater than in South Korea, where Japanese music had been banned for years. That restriction was lifted in late 1999, and within months Japanese acts ruled the Korean charts.

But K-pop has since conquered Japan: Kara, 2PM, T-ara, Beast and (of course) Girls' Generation own the Oricon charts. And they've essentially done it by making a better version of J-pop. (Kara's "Go Go Summer" is, for example, probably the best single Japanese legends Speed never made.) Where the J-Poppers work in a style easily reproduced at the karaoke bar, the K-pop approach is virtuosic and polished, with sharper, almost militaristic choreography.