Michiko is born the 1st of February and has a brother. Raised in the same village as Yoshika, Michiko (called Micchan by her friends) attended Yokosuka 4th Girls-only Middle School alongside her. She sometimes brings Yoshika wounded animals to heal at the Miyafuji clinic, and has been healed by Yoshika's magic once herself.
She is very interested by warships and witches, and particularly enjoys reading detailed specifications of warships. Micchan's favorite warship of the Imperial Fusoan Navy is the Takao, of the Takao-class heavy cruisers. She already was a witch enthusiast, but this has escalated since Miyafuji joined the Navy and she is now very knowledgeable about famous witches from all over the world.
After graduating from junior high school, she chose to go to a teacher's training school to become a teacher, but secretly dreams of joining the Navy to become Miyafuji's cadet.
- Strike Witches season 1
- Strike Witches season 2
- Strike Witches Movie
- Strike Witches: 501 Butai Hasshin Shimasu!
- Strike Witches: 501 Butai Hasshin Shimasu! Movie
- Strike Witches: Maidens in the Sky
- Strike witches: Chii Sanya, cameo in chapter 4
- Strike witches: Chii Size
- Strike Witches: The 501st Joint Fighter Wing
- Strike Witches: 501 Butai Hasshin Shimasu! Movie (manga)
- Strike Witches: Kiseki no Rondo, in a group card
- The name Michiko means "beautiful" (美) (mi), "wisdom, intellect" (智) (chi) and "child" (子) (ko).
- Michiko's surname Yamakawa means 山 (yama) meaning "mountain" () (yama) and "river" (川 or 河) (kawa).
- While not a witch canonically, she did receive a mockup as one by Humikane.