Yes, out of the cobwebs of my mind. I heard this once more after years and years, and the nostalgia, oh the nostalgia, started flowing through the arteries again. This is Gamu's（雅夢）"Ai wa Kagero", the folk duo's oh-so-tenderhearted debut song from September 1980. Kazuto Miura（三浦和人） and Toshikazu Nakagawa (中川敏一...I hope I got that last name right) formed Gamu (elegant dream) sometime in the late 1970s while studying at Chukyo University in Nagoya.
In May 1980, the pair entered the 19th annual Yamaha Popular Song Contest with "Ai wa Kagero" that Miura had written and composed, and subsequently won a prize in composition. It wasn't too long before it was released as the official debut and became Gamu's biggest hit, selling close to 700,000 copies. The song would also become the 13th-ranked single for 1981.
I've seen "Ai wa Kagero" translated as "Love is a Heat Haze" but I'm wondering if "Love is Fleeting" wouldn't have been a more romantic way to express it. It may have been a folk song but there is also that hint of European sentiment which gives it another interesting dimension to my ears. I guess with the additional fact that I am also a big fan of Taeko Ohnuki（大貫妙子）from her early 80s pop music with a French twist, I probably have an affinity for that particular fusion of music from two different continents.