I believe I've seen Korean-born singer Cheuni（チェウニ）at least a couple of times on NHK's "Kayo Concert" since the name rang a bell. According to J-Wiki, she made her debut in 1972 at the age of 8 before releasing a Japanese album in the late 1970s, although it was in her native South Korea where she had her first hits into the 1980s.
However in 1998, Cheuni took another stab at fame in Japan and (re-)debuted with "Tokyo Twilight" in September 1999. Written by Yuko Natsumi（夏海裕子）and composed by Masato Sugimoto（杉本真人）, the song sounded like the 2nd coming of Teresa Teng（テレサテン）although I realize that Cheuni sounds a fair bit different from the late Teng. But there is something about the arrangement of "Tokyo Twilight" that made me think that this would have been a tune that Teng would have tackled. And that same arrangement has a somewhat natsukashii flavour since it feels like something that I would have heard almost a decade before. I would describe it as an urban and wistful melody that could be heard as a turn-of-the-century type of City Pop.
Cheuni won a Newcomers Prize at the Japan Record Awards in 2000 for "Tokyo Twilight". Her debut would start off a series of Tokyo-based songs which included her next two singles, "Tokyo ni Yuki ga Furu"（Tokyoに雪が降る...Snow Falls in Tokyo）and "Hoshizora no Tokyo"（星空のトーキョー...Starry Night of Tokyo）.