Yoko Kagawa（佳川ヨコ）is another one of those singers that I haven't been able to glean a lot of information about, although her discography is listed at "Showa Pops". I don't know where she comes from, how she got into the singing business or whether she's even still alive. What I do know so far is that she made her debut in February 1967 with "Kimi Koso Waga Inochi"（君こそわが命）. Now for those kayo experts, if that title sounds familiar to you, it's because Hiroshi Mizuhara (水原弘) also released the same song in the same month as Kagawa, and it has become one of his trademark tunes. The debate goes on as to who released it first, though, and unfortunately I haven't been able to find Kagawa's version of the song online.
However, Kagawa's star really rose with the release of her sophomore effort, "Ginza no Maria" (Maria of Ginza) later that year according to what I read on one fellow's 2006 blog entry titled "Wasureta koro ni Kagawa Yoko"（忘れた頃に佳川ヨコ...The Forgotten Yoko Kagawa）. This is an interesting song by her in that although it is listed as a Mood Kayo (and I believe that genre choice, too), not only can I still hear some elements of enka in the arrangement and Kagawa's vocals but there is also that twangy guitar twist rock in there as well that I would usually associated with Group Sounds which had its heyday during that time. Give thanks to composer Yasumi Matsuo（松尾安巳）for this somewhat gestalt kayo.
Lyricist Kohan Kawauchi（川内康範）, the same man who was behind the words for the aforementioned "Kimi Koso Waga Inochi", was also responsible for "Ginza no Maria" in which the protagonist, a hostess, has proudly proclaimed herself to be the Mary Magdalene of the glamourous Ginza with her clients all coming especially to her for succor and sympathy. Never did I ever think that religious idioms would be made in this particular neighbourhood, but whether this hostess actually believes her own press or is being rather tongue-in-cheek about it is up to the listener. For me, Kagawa's breathy and varying vocals seem to be giving knowing winks to my ears. Her voice is a mix of Auntie Mame, teasing experienced hostess and traditional enka chanteuse.
Kagawa was regularly releasing singles up to the middle of the 1970s but it looks like "Ginza no Maria" was her one big hit. However, I want to see if there are any more examples of her work on YouTube.