Ahhh...the evergreen visage of the lovely Naoko Kawai（河合奈保子）with that cute snaggletooth. She had me as soon as she popped onto the stage to perform "Smile For Me" on the 1981 Kohaku Utagassen. She could have out-aidoru-ed Seiko-chan that night.
The last few nights I did a couple of articles which featured songs which had the same title of "Summer Blue" by Bread & Butter and Sayuri Kokusho（国生さゆり）but with totally different music and lyrics. That sort of thing isn't particularly new to me since there were 3 pop songs with the title "Sotsugyo"（卒業）in the 80s and 90s. But I found out tonight of another example involving Kawai. Her 4th single from March 1981 was "Juu-Nana Sai" (17 Years Old), the single immediately preceding that breakthrough of "Smile For Me", and the namesake of the far more famous song by Minami Saori（南沙織）from the early 70s.
Unlike the cheerful Saori classic, Kawai's "Juu-Nana Sai" has a bit more uncertainty in the melody and lyrics as she sings about being in a quandary at that titular age. As the words go, neither girl nor woman, neither little sister nor friend, there is that identity crisis in regards to the vagaries of love, although the refrain goes briefly into a major key of hope as she exhorts her heart to tell her the right way.
The lyrics were written by Machiko Ryu（竜真知子）and the music was provided by Kimio Mizutani（水谷公生）who composed "Hop Step Jump" for Hideki Saijo（西城秀樹）some years earlier and later arranged a number of the late Kozo Murashita's（村下孝蔵）songs including his biggest hit of "Hatsukoi"（初恋）in 1983. "Juu-Nana Sai" peaked at No. 11 and later became the 75th-ranked song of 1981.