the main character of K-On!. She is one of the members of the light music club, and plays a Cherry Sunburst Gibson Les Paul Standard electric guitar that she nicknames ''Giita''. She does not get good grades in school and is easily distracted by trivialities. Yui is clumsy and easily spaces out most of the time. She takes a huge liking for any kind of food, but admits that she does not gain any weight. She has her younger sister Ui to take care of her and keep herself in line. She has a very easy-going nature, but has incredible concentration when hyped, though this is only limited to one subject at a time. She will totally neglect any other things in the process, to the point of forgetting anything she has learned beforehand. Despite all of this, Yui is still devoted to her band and will practice hard enough for the club. She has perfect pitch and is one of the group's vocalists, although she is known to forget her lyrics in mid-performance, as well as overdoing things, making her unable to perform sometimes.