1983 saw Koizumi emerge with a more boyish image and synthesizers began to take a more prominent place in her music, notably on the singles Makka no Onnanoko and Adesu ga Amida Musume. It also saw the beginning of a run of Top Ten singles that remained unbroken for more than 12 years, until 1995's Beautiful Girls. From 1984 and 1985, Koizumi's image shifted in a more mature direction, incorporating more of an influence from rock and new wave, with songwriting and arrangement contributions by new wave and techno-pop luminaries such as Masahide Sakuma of the Plastics, YMO collaborator (and Ryuichi Sakamoto's then wife) Akiko Yano, and Kenzo Saeki of Halmens and Pearl Brothers.
As the '80s drew to a close, Koizumi began to shift between styles more frequently, with the house-influenced Fade Out, written by Haruo Chikada reaching number two in the charts in 1989. In 1990, she began writing her own lyrics, and collaborated with Tokyo Ska Paradise Orchestra on the song Oka wo Koete. 1994's My Sweet Home, with music by Takeshi Kobayashi (later of My Little Lover) pointed the way to the slick J-Pop sound that would come to dominate the late '90s.
By this point, however, Koizumi's successful acting career had come to overshadow her music and her releases became sporadic, drying up almost completely by the end of the '90s. Nevertheless, she continued to make occasional returns to the musical arena, releasing the album Atsugi I.C. in 2003 and Nice Middle, featuring collaborations with Tokyo No.1 Soul Set and Asa-Chang, among others, in 2008. ~ Ian Martin, Rovi