"Sumire Iro no Namida"was released in June 1981, and peaked at No. 6 on the Oricon weeklies before ending up No. 45 on the annual single charts. She personally won a Japan Record Award and appeared in the 1981 Kohaku Utagassen where she showed her tender side by weeping into the second verse which got all of the other female singers to rally around her.
Iwasaki's heartful rendition, though, was actually a cover. The original singer was Jackey Yoshikawa and his Blue Comets in 1968. It was the B-side to the group's 11th single, "Kokoro no Niji"（心の虹....Rainbow of the Heart）which came out in January of that year. That single peaked at No. 5 on Oricon. (Their cover comes at around 2:45 of the above video)
Here is Iwasaki herself performing the song on stage. By the way, "Sumire Iro no Namida" was written by Yukiko Marimura（万里村ゆき子）and composed by Hiroshi Oda（小田啓義）.