This sounds like the quintessential Sunday afternoon song. Gentle and slightly breezy with a good amount of sun, "Yureteita Kokoro" (Emotional Heart) is a track from songbird Etsuko Sai's（彩恵津子）2nd album "All I Need" released in March 1985.
The album was produced in Los Angeles with Sai writing the lyrics for this particular track and Al Boyd along with Parvene coming up with the music, so there is something quite pleasantly West Coast AOR about it. In a way, I think the song was a bit ahead of its time since the combination of keyboards and Tim Weston's guitar makes it feel more like a product of the late 1980s or even early 1990s. No matter which part of the time stream it feels like, though, "Yureteita Kokoro" makes for the ideal musical accompaniment while swinging slowly in the hammock while looking up at the cumulus clouds.