Compared to junior high school

After graduating elementary school, children enter a junior high school. It is also compulsory education in Japan.

In junior high school, many things are different from that of elementary school. So some children suffer from the gap. It is called "中一(first year of the junior high school) ギャップ(gap)".
I show you some example of the gap. For one thing, there is a change about their teachers. In junior high school they have teachers who take charge of each subject while homeroom teacher teaches almost all subjects in elementary school. Another big change is introduction of  English as a subject. Club activity is also a new thing. Furthermore,they will encounter many changes.