I really enjoy the cool urban feeling from Junko Yagami's（八神純子） "Naturally". This was her 17th single released in August 1983, and while Yagami was behind the City Pop melody, Keisuke Yamakawa（山川啓介）took care of the lyrics. The song seems to be divided into two parts with the first part starting off with this rocky twang and expressing the steamy sultriness of enjoying a hot time in the big city, before the refrain changes the key to a more upbeat and perhaps more idealistic tone of returning to the real world of work and finally finding that Mr. Right. I guess in a phrase, it's kinda like "Disco Queen by night, Office Lady by day".
The song was also the theme for a TV Asahi drama titled "Onna tachi no Kagai Jugyo" （女たちの課外授業....Women's Extracurricular Classes）which may hint at that two-sided life. It is also a track on Yagami's 1983 album, "Full Moon".
The above is a tribute performance by Six "I"s.