However, what connected The Manhattan Transfer and Hi-Fi Set in my eyes was this song, "Koi no Nikki"(The Diary of Love), their 10th single released in October 1977. It's straight away jazz vocal that The Transfer could sing just as smoothly. I'd have to put this along with the country version of "Tsumetai Ame"（冷たい雨....A Cold Rain) as my favourite tunes by the trio, since I love the mellow horn section and the languid strumming of the electric guitar accompanying the vocal harmonies.
The crazy thing is that this jazzy ballad was originally a 50s R&B tune by none other than Neil Sedaka who composed the music while Howard Greenfield came up with the lyrics. Haruko Iwatani（岩谷晴子）provided the Japanese words for Hi-Fi Set's version.