|Age||5 (chapters 1-232)|
6 (chapters 233-present)
|School||Unnamed Elementary School|
Genzaburō Karamatsu (grandfather)
Yui (younger sister)
|Manga Debut||Chapter 40|
|Anime Debut||Episode 22|
Yoshihiko (吉彦) is the Principal's grandson.
Yoshihiko's grandfather often talks about him being intelligent and a high achiever. In reality, he is a quiet, spoiled boy whose parents haven't allowed him to make friends or play rough, making him seem cold and dull for such a young child.