Going with something more folksy to start off the weekend from a couple of singers that I have never heard of before.
"Sayonara wo Iu Mae ni" (Before We Say Goodbye) is a somewhat bittersweet folk ballad that almost comes across as a lullaby. As far as I know, it was first created for folk singer Keiko Kobayashi（小林啓子）for her debut album "Agemasu"（あげます...I'll Give It To You）in December 1971. Written by Toshio Fujita（藤田敏雄）and composed by Hachidai Nakamura（仲村八大）, the kayo veteran behind such songs as "Ue wo Muite Arukou"（上を向いて歩こう）, the song may not have been meant as a lullaby but it's certainly hinting at the permanent sleep for a relationship. However, it sounds sweeter than bitter as if the soon-to-be former couple realizes that although their relationship has come to an end, the good memories are still there.
I also found this video of another version of "Sayonara wo Iu Mae ni" and managed to find out that it was sung by Yumi Inui（いぬいゆみ）who apparently has very little information about her. I could only piece out that her cover was on the B-side to her 1976 EP "Shiki no Uta"（四季の歌...Song of the Four Seasons）. The arrangement is slightly different. Perhaps I can say that it's even folksier than the original version in that Kobayashi's take has a slightly more TV-friendly 1960s kayo feeling.