There are a couple of observations that I have for the vocal group Hi-Fi Set（ハイ・ファイ・セット）. First off, for a group that had their heyday in the 1970s, Junko Yamamoto（山本潤子）, Toshihiko Yamamoto（山本俊彦）and Shigeru Okawa（大川茂）have had a lot of representation on YouTube. It's great to see a lot of their videos there. Secondly, and perhaps this may not be totally accurate, my impression is that the group seems to enjoy singing about school-related stuff.
Case in point: their "TWO IN THE PARTY", a track from Hi-Fi Set's 8th album "Quarter Rest" from 1979. With lyrics by Mami Kikuchi（菊池まみ）, the Yamamotos and Okawa croon about a young lady, perhaps in her twenties, looking forward to what seems like the swankiest school reunion in the city. More importantly, the lass is anticipating catching up with an old friend (wink, wink). There are even some party sound effects to add to the atmosphere.
The music by mellow composer Tetsuji Hayashi（林哲司）starts off with a funky riff that sounds a lot like it came from an R&B song I used to hear on radio here in Toronto back in the 1970s so I'm wondering if there had been some liberal borrowing. However, the music then heads back into familiar Hi-Fi Set territory with a mix of swingy jazz and downtown feeling. Of course, there are those wonderful harmonies by the trio. May want to pick up some of those old albums of theirs in the near future.