In 1993, she released Compact Cassette single "Tsugazakura" (つがざくら lit. "Phyllodoce Nipponica") as "Nana Kondo". However, she passed the audition of game Noël: La Neige and became a seiyuu.
I joined Nana Mizuki Fans on facebook.
Since she is trained as an enka singer, No wonder she sang enka. Her voice is beautiful and I cannot imagine that from listening to jpop, I now listen to her enka song here.
http://www.facebook.com/video/video.php?v=133000716720830&ref=mf (must join this facebook fanbase first)
UPDATE AUG 6, 2010: (for those lazy to go to facebook here is her enka performance:)
Others::
