I've been enjoying Naoko Kawai's（河合奈保子）"Jewel Box 2" set of 5 CDs (with thanks to Michael Wishlow) from 2003 over the last number of months. Disc 4 has been quite interesting since it has all of the rare takes of the singer...songs that were never placed directly into Naoko-chan's discography but were contributions to other compilations or media. I read that there were a couple that had never been placed on any listenable media before "Jewel Box 2" since they were only utilized as music on her videos.
One of the rare songs was Track 12, Kawai's rendition of the kayo classic "Aoi Sanmyaku" (Blue Mountain Range) which I have already written about. What struck me about it was the arrangement by composer-arranger Katsuhisa Hattori（服部克久）, the son of the original composer Ryoichi Hattori（服部良一）. From my ears, Hattori fils seems to have given "Aoi Sanmyaku" a taste of 1970s disco orchestra as applied to some of the anime back then such as "Uchuu Senkan Yamato"（宇宙戦艦ヤマト...Space Crusier Yamato）and "Macross"（マクロス）. Being fans of both shows and their soundtracks, Kawaii doing this number immediately perked up my ears. I was half-expecting a fleet of Black Tigers and Valkyries to come storming over that mountain range.
It took a bit of tracking down but I found out that this somewhat funkified version of "Aoi Sanmyaku" had originally been part of a 1985 tribute to Hattori pere in the form of a two-record (2-CD?) album titled "SHOWA RHAPSODY ~ Hattori Ryoichi Sakuhinshuu"（服部良一作品集...The Ryoichi Hattori Collection）. Not sure if this collection is even available outside of scouring the auction sites since I didn't see the album pop up readily on the search engines. As a kayo fan, I would be intrigued in finding out what some of the other tracks are like.