The Fourth Keihan Girl.
Here is the fourth O-Kei-han she is really cute, her alias is Keiko Kuzuha, her "real" name is Chiho Hinata. She's probably the youngest of the girls chosen as O-Kei-han at 19. Unlike the other girls she's way more famous, you can find lots of info on her if you seach on her "real" name (I'm not sure if that's her real name or a stage name).
Here's a page I found on O-Kei-han, but I have to disagree with him, I think the even numbered one are better than the odd numbered ones.