Oumihara Chuugaku Shintaisoubu (大海原中学 新体操部, lit. Oumihara Jr. High's Rhythmic Gymnastics Club) is a location.
It first appeared in episode 4. It was revealed by the three unknown members of this club that Nozaki Sakura was previously a member of it. One of the members was surprised that Sakura was playing for Japan's national soccer team, but the other two said that it was a good thing that she had left the club. They also said it was unlucky for the rest of Inazuma Japan to have her on the team, in which they agreed.
During Inazuma Japan's match with Big Waves, they were shown again watching the match and continuously commenting on Sakura's actions; which they deemed to be unreasonable.