Background
Kokushō was named after Sayuri Yoshinaga, of whom her father was a fan. She then attended Shimizugaoka High School in Kure, Hiroshima due to her father"s transferring from JMSDF Kanoya Air Base to JMSDF Kure Naval Base while in the Japan Maritime Self-Defense Force.
Education
After spending time living in Sasebo, Nagasaki when she was young, she attended Nishihara Elementary School and First Kanoya Junior High School, both Kanoya Municipal schools.
Career
She works for the talent management firm Sony Music Artists. Her debut single, Valentine Kiss, is the most popular Valentine"s Day song in Japan. While in high school, she represented the Chūgoku region in the 3rd Mission Seventeen Contest in 1984.
Because she was attending a high school in Hiroshima Prefecture at the time, she was described as being from Hiroshima.
She was the captain of the track and field club during high school. Onyanko Club era
However, the "public image" leaders of the group were promoted as being Eri Nitta, Miharu Nakajima, Satomi Fukunaga, and Kazuko Utsumi.
Kokushō continued to stand out as a leader of the group, however, even with publicity surrounding the solo debut of fellow member Sonoko Kawai. She received some support from Nitta and Kawai, both of whom had started successful solo careers of their own.
She made her solo debut on February 1, 1986 with the single Valentine Kiss, which was backed by Onyanko Club.
The single reached #2 on the Oricon charts, #1 on the Music Laboratory and Music Research charts, and #4 on the The Best Ten music program on Turner Broadcasting System. In a 2006 survey in Japan, Oricon Style found Valentine Kiss to be the most popular Valentine"s Day song. She was not, however, able to match the Oricon #1 position reached by Nitta and Kawai with their respective solo debut releases. From November 2008 onwards, Kokushō has made sporadic appearances for professional wrestling promotion Oz Academy, working as the manager of the villainous Ozaki-gun alliance.
Membership
Onyanko Club]
She was an original member of Onyanko Club. After winning the in-show beauty contest, she made her debut on Yūyake Nyan Nyan as a founding member of Onyanko Club. On April 25, 1985, Kokushō made her professional debut as a founding member of Onyanko Club (member #8).
Because she had already graduated from high school and was attending college, she was senior to most of the other members of Onyanko Club and became the de facto leader of the group.
Kokushō then had to determine whether she wanted to continue as a member of Onyanko Club or begin a solo career and leave the group.