Man, I didn't realize that Yoko Minamino（南野陽子）had such a good run of consecutive No. 1s. Her string of chart-toppers ran from Single No. 6 "Rakuen no Door"（楽園のDoor）which was released in January 1987, through her 11th single "Toiki de Net"（吐息でネット）, all the way to her 13th single "Aki kara mo, Soba ni ite"（秋からも、そばにいて...Stay by my Side, Also from the Fall）from October 1988...a good chunk of 2 years. And the powers-that-be really had her spitting out those singles within a relatively short period of time.
Also within that string was her 9th single "Aki no Indication" (Autumn Indication) from September 1987 which I had never heard before. Written by Eiko Kyo（許瑛子）and composed by Mitsuo Hagita（ 萩田光雄）, that melody was the thing that hooked me since it sounded rather exotic for a lack of a better word. But then again, I have said that a number of the aidoru tunes from the late 1980s went farther afield in terms of their music; I guess that aidoru-dom was following in the footsteps of some of that exotic kayo which had been released a decade earlier.
The song sounds as if it took a bit of European into itself. And according to the J-Wiki article, Nanno herself had been interested in a 1960s song by Italian pop singer Wilma Goich titled "In un fiore" (In A Flower), so I gather that Hagita was inspired by some of that melody to create "Aki no Indication". As mentioned, it did hit No. 1 on Oricon and became the 33rd-ranked single of 1987. It was also used as the commercial song for the Cecil chocolate bar from Glico. Nothing says fall more than a piece of milk chocolate, apparently.