Obi wo Gyutto ne!

Takumi Kogawa and Osamu Sugi from Northern Junior High School, Koji Saito from Southern Junior High School, Shigeru Miyazaki and Yukihiro Mimizo from Eastern Junior High School, and Honami Kondo and Sakurako Ebizuka from Takamachi Junior High School meet at the judo dan promotion meet in July of their final year in junior high. About half a year later, they all enrolled in Hamanako High School, where they met again in the same class. They immediately try to join the judo club, but there is no judo club at Hamanako High School, so Ryuko Kurata (3rd dan in kendo), who is also their homeroom teacher, is appointed as their advisor to start a new judo club.

(Source: Wikipedia Japan, translated)