Keiko Yamamoto is a classmate of Doremi, Momoko and since Dokkan, of Hana. In 3rd and 4th grade, she was in the former class 1. She is the character of the day during "The Class Library's Combination is Missing!?.
Keiko has fair skin and slanted, grey eyes. Her dark grey hair is shoulder length with a fluffy flip on the end, and short, straight cut bangs. She has thick, curving eyebrows.
Keiko wears an indigo blouse lined in white with buttons to match, a white skirt, pale indigo and white sneakers, and short white socks.
Keiko is naturally stern and serious. But after she meets Hana-chan and gets to know the girls, she learns to become flexible.