I guess this is the day for "Parting is such sweet sorrow" songs. Took care of a 1970s bittersweet folk song some minutes ago, and now I'm jumping ahead by a couple of decades for something similar but poppier.
"Tsuioku" (Reminiscences) was Stardust Revue's（スターダストレビュー）23rd single from January 1992, and it's a heart-and-soul ballad about a person who may have long parted with someone but still carries that torch. There was nothing written about this song on J-Wiki but I think it still packs an impact thanks to the lyrics by Toyohisa Araki（荒木とよひさ）and the gospel-influenced melody by vocalist Kaname Nemoto（根本要）. And the way it comes across, I think that "Tsuioku" would make for the perfect sunset song. Plus, depending on one's mood, perhaps a few tissues may be in order.