Yoshiya was born in Niigata Prefecture, but grew up in the cities of Mooka and Tochigi, in Tochigi Prefecture. Her father was in the public service, so her family often moved. She was the only daughter and youngest child of her family. Both, her mother and her father, came from samurai families. She started writing when she was in her teens, although before this she had developed a love for writing which sapped her time for learning domestic skills from her mother.