Cover songs have often been interesting to...cover because I've been keen on how everyone involved in the recording including the singer approaches the original from their own angle. Is it more upbeat or downbeat? Has it gone through a genre filter...instead of the original pop version, has it gotten a bossa nova or technopop treatment? When it comes to cover songs, the one that came off the top of my head was the recent Masayuki Suzuki（鈴木雅之）more soulful cover of Ikimonogakari's（いきものがかり）"Kaeritakunatta yo"（帰りたくなったよ）. Plus, there is also one of my favourites, Miho Yonemitsu's（米光美保）take on Minako Yoshida's（吉田美奈子）"Koi wa Ryuusei" (恋は流星）which almost equals the original. Generally speaking, though, covers are fine but they usually don't quite overtake the first versions of songs.
And that's my opinion as well for Shoko Morioka's（森丘祥子）version of "Tsumetai Ame" (Cold Rain), the classic New Music tune penned by Yumi Arai（荒井由実）back in the 1970s and sung by her and also vocal group Hi-Fi Set. Still, not too bad a cover. Her cover is slightly more measured in the delivery and the arrangement seems to have gotten the Eiichi Ohtaki（大滝詠一）treatment via those 90s synths. In fact, that was when her song was released as a track on her lone original album "Pink & Blue" in May 1990. Morioka would release an entire album of cover songs in the following year, "Yume de Aetara"（夢で逢えたら...When We Meet In Our Dreams）.
As for Morioka, she was born Kuniko Shibata（柴田くに子）in Gifu Prefecture in 1967 and got into show business following the Miss Seventeen contest for "Seventeen" magazine in 1984. Shibata and two others who won their respective prizes in the contest were then put together as an aidoru trio called Seventeen Club. They would release two singles in 1985 before breaking up. Shibata then took on the Morioka stage name once she debuted as a solo singer in 1990 but it looks like from her J-Wiki article that she reverted back to her real name.
Oh, as for one of those two contest winners who became Shibata's partner in Seventeen Club? She was none other than Shizuka Kudo（工藤静香）who would later join Onyanko Club（おニャン子クラブ）and enjoy further fame and success.