noun
class change; class shuffle; rearrangement of students into new classes
Refers to the annual school event where students are reassigned to different homeroom classes, typically at the start of a new school year in Japan.
来月、クラス替えがあるから、誰と同じクラスになるか楽しみだ。
Next month there's a class shuffle, so I'm excited to see who I'll be in the same class with.
クラス替えの結果が掲示板に貼り出された。
The results of the class rearrangement were posted on the bulletin board.