Kazuhiko is Masaki's cousin. He is the same age as him and works in a ryokan located in their hometown.

He meets the Fujiyoshi family for the first time when Masaki returns to his hometown to retrieve a letter his uncle wanted to give him. His uncle informed his son Kazuhiko of their visit, so that Masaki, his family, and their friends could stay at the ryokan where Kazuhiko is employed.