I believe I mentioned a bit about this song by veteran singer Yukari Ito（伊東ゆかり） in the first article about her, "Koyubi no Omoide"（小指の思い出）. For all of the attention paid to her hits back in the 1960s, ironically enough, the very first song I ever heard by Ito was this one, "Yakusoku Dake Romantic" (Just A Promise Is Romantic) via "Sounds of Japan". Released in August 1981, of course, it doesn't sound like any of her earlier stuff but now that I've heard her hit songs from the 60s, so coming back to this first taste of Ito through this gentle mid-tempo ballad is pretty clean and refreshing (hark, I believe I have just described a glass of Sprite). I wouldn't say it quite fits the City Pop idiom but it has that Western sound with the Japanese twist which would put it in the New Music category.
In any case, it's a lovely song which is helped by Ito's elegant and rich vocals. Written by Yoshiko Miura （三浦徳子）and composed by Toshikazu Sase（佐瀬寿一）, I was finally able to acquire my own copy of "Yakusoku" via her "Golden Best" compilation. In a way, the song reminds me of the tunes that Mariko Takahashi（高橋真梨子） was singing at around the same time.