So Marty Friedman is not Japanese, in case you didn't know. In fact, he hails from the same town I'm currently living in. It wasn't until a few years ago that I learned he had anything to do with Japan, actually. No, my knowledge of him was much more traditional.
During high school I developed a taste for rock music that over time grew and matured such that my college years were partly soundtracked by the likes of Metallica, Megadeth, Jethro Tull, Blind Guardian, and a number of other heavy metal bands of varying notoriety. And so my exposure to Marty Friedman can be credited to his role as lead guitarist for Megadeth.
A few years ago I remember Dylan mentioning on a tangent to some conversation that Marty Friedman had moved to Japan and spoke perfect fluent Japanese. "Cool," I thought, but it didn't really register.
Fast forward to now. A couple weeks ago I met and caught up with a friend that I hadn't seen in 6 or 7 years, since we studied together at 上智大学 (Sophia University) in Tokyo. She lives in NYC now, and I was in town for a couple days. Turns out she is a big metal fan, and we got to talking about different bands and artists. The other day she sent me this awesome video of Marty Friedman and Paul Gilbert on a Japanese TV show:
There are two more parts, if you care to watch. I think it's pretty rad seeing those guys rock out and speak Japanese. After watching, I did a little research. It turns out that Friedman has been living in Tokyo for about 10 years now, and last year he married a Japanese cellist. He's been a regular on several music and English-themed TV shows over there, and has done cameos in other media. He still plays, and perhaps most notably for you anime/game fans, he's a member of Sound Horizon.