Ren Xu school system Ren Xu school system is the longest and most influential school system in modern China, and its six, three and three periods still affect the education in China. Ren Xu's academic system refers to the Beiyang government's summary of the teaching methods and teaching process developed by the school since the Republic of China 1922. According to the three-stage teaching method, a class is divided into preview stage, experience stage and the basis for learning from the experience of western education system.