>>58034291
[schizo rambling and cospiracy]
The answer is simplier than you think OP, k-pop is growing big in Japan and just had its peak globally. That's it, that's the reason, really. He fits the typical k-pop fashion style, mixing Western with Asian and fullfilling the female desire for pretty boys with sophisticated looks.
Pic related, I don't even know who they are but they give you a quick idea of k-pop. You can find several other bands with similar looks. Some Japanese fashion styles for males are also similar before the whole k-pop explosion.