Yamaguchi Yuriko was born November 21, 1965 in Osaka Prefecture, Japan. She is a voice actress (seiyuu). Yuriko was initially part of 81 Produce, but went freelance, then joined Vi-Vo. Currently she affiliated with Aoni Production. Her real name is written a bit differently (山口百里子), but read the same way.
Eiko Jinno and Yoshiko Nikaidou are aliases used by Yamaguchi Yuriko for adult games and anime.