For reasons I grade "Momen no Handkerchief "as the greatest and most-underrated song of the 1970s:
I always thought the melodies were really unique and didn't flow naturally -- it took a while for it to really sink in. But it was after I was able to read a translation of the lyrics that the song hit me hard. The tune seems to have has that pep and skip but really, it's unique in that it's a back and forth between lovers on a downbound train. I couldn't believe how heartbreaking this famous song really was.