[1][2] Mari Amachi was the top female vocalist of Sony Music Entertainment in Japan.
[6] She was promoted alongside Rumiko Koyanagi and Saori Minami, and they were dubbed the "San-Nin Musume" (Three young girls).
[15] By the summer of 1972, her single "Hitori Janai No" had sold over 600,000 copies and proved to be her second #1,[8][16] and she was invited to perform on the 23d edition of Kōhaku Uta Gassen.
[18][19] The following year, Mari Amachi and fellow idol Hiromi Go were reported to be responsible for grossing more than $45 million for Sony Music Entertainment.
[24] In 1977 Mari Amachi withdrew from public life citing thyroid problems, although she later admitted she was suffering from a depression.
[25] In 1979 she returned to showbusiness, and was welcomed back with a large press party at CBS Sony's recording studio.