After the contest, musician and producer Tsunku offered Nakazawa and the four other runners-up (Natsumi Abe, Kaori Iida, Aya Ishiguro, and Asuka Fukuda) the chance to be taken under his wing under one condition: they must sell 50,000 CDs of their debut song "Ai no Tane" with five days of live promotion.
In 1998, shortly after Morning Musume's formation, Nakazawa began a solo career, beginning with enka styled songs.
Being the oldest of the 1st generation of Morning Musume—she was 24 at the time of formation and nearly 28 upon leaving the group—Nakazawa held the role of the group's leader until her graduation on April 15, 2001.
Since then, Nakazawa has done some work in Japanese dramas such as Beauty 7 and Home Maker, performed in various plays, and continued in her solo singing career at a steady pace with reasonable success.
[1] On February 1, 2009, during the "Hello Pro Award '09 ~Elder Club Sotsugyō Kinen Special~" concert held at Yokohama Arena, Nakazawa passed on her leadership position in Hello!