The graduates of the three years of 1966, 1967 and 1968 from junior high schools and senior high schools are collectively called "the old three classes".
"The old three classes" refers to the three classes of students in junior and senior high schools at the beginning of the Cultural Revolution. Later, these people basically became educated youths. In the later period of the Cultural Revolution, there were also students who continued to leave school from middle schools. The latter few sessions were also called "new three classes". Many of the new three classes also went to the countryside and became educated youth. The educated youth of the old three classes basically went to the border areas, such as Beidahuang in Northeast China, Xishuangbanna in Southwest China, and Inner Mongolia. After the fall of the Gang of Four, the movement of educated youth going to the mountains and countryside also stopped. These old three classes generally served as Red Guards.