It's possible that:
* Her name is spelled differently in English. It might be worth searching for variations like "Mitsuko Kimura" or "Michuko Ichimura."
* She is more prominent in Japanese cinema. To find more information, you might have to search Japanese websites and databases.
* She is a stage actress. Many accomplished actors have careers primarily in theater. It's possible she focuses on stage work rather than film and television.
If you have more details about her, such as a specific movie or role, it might be easier to find additional information.