Yuko Ishikawa（石川優子）....a name that I've heard now and then over the decades but never really got to know. The only song I know that she's been associated with is "Futari no Ai Land"（ふたりの愛ランド）(1984), her duet with Chage of Chage & Aska fame due to it being a popular karaoke song at Kuri way back when.
Still, I'm more than willing to rectify the situation even at this late date. I've tried to read up on her via J-Wiki and anything else I can find on the singer-songwriter. One of the phrases that I've seen a fair bit about her is that despite her cute looks, she quite firmly declared that she wasn't an aidoru, and this was during a time when aidoru were pretty much popping out of the woodwork.
I've come to her 7th single, "Cinderella Summer" that was released back in March 1981. The single version has that appropriately summery sound with the wailing electric guitar that makes me think that this would have been ideal for the aidoru of the early 80s, Seiko Matsuda（松田聖子）. However, it was Ishikawa who composed, wrote and sang this beach-friendly song with that hint of 50s. I could be transported back to those days on the graduation trip to Japan listening to this.
Took a bit of searching around but I was able to track down on a Japanese-language blog that "Cinderella Summer" managed to peak at No. 10 on Oricon and sell over 330,000 records. The tune eventually became the 42nd-ranked song of the year.
The song also got onto the album of the same title which was released in June 1981. Unlike the single version, the album version has a slightly more techno kayo sound to it without the wailing guitar. No complaints from me.
Not surprisingly, "Cinderella Summer" was used as the campaign song for Japan Air Lines Okinawa in that year. I could imagine tourism getting a nice boost from it.