Sakai was also a very prolific lyricist. She wrote 150 songs during her 17-year career (numerous songs for other artists as well as all of the Zard songs except for two, and from their first album, "Good-bye My Loneliness", which was written by Daria Kawashima,) and released several books of poetry as well. An editorial in "Asahi Shimbun" writes that the secret to Zard's success was that while the trend in Japan showed a decrease in the number of music programs on television, Zard used late night commercials that aired her voice to advertise her works.