Sasaya was born on January 31, 1950, in Ashibetsu, Sorachi Subprefecture, Hokkaido, as the youngest in a family of four children.
Despite the wishes of her father, who wanted his four children to become teachers, she chose to pursue a career as a manga artist.
[1] At the age of 20, she began working in the manga magazine Ribon, where she became known for her horror stories with occult themes.
[2] In 1990, Sasaya won the Excellence Prize at the 19th Japan Cartoonists Association Award for her manga series Okamehachimoku (おかめはちもく), an autobiographical manga about her life with her husband.
[3][4] In 1994, after reading Oya ni Naruhodo Muzukashii Koto wa Nai (親になるほど難しいことはない), a book about child abuse by journalist Atsuko Shiina（椎名 篤子）, she adapted the book into the manga Kōritsuita Me (凍りついた瞳, lit.