Zhu Ziji leather, training people said: "learning to do, only for the trial, heart and principle, natural hair is selfless. Saints should all things, heaven and earth, straight just carry." Straight is sincere, is the immediate present conscience, is the unity of knowledge and action, is utter innocence, is the sage should things of the heart, is the world of heart, and me "to take will be with" heart heart heart is Machiavellian, partiality, movement, cheat heart, dark heart, can not see the light of day in the heart. Compared with the two kind heart, should use what kind of heart to teach children, is the most obvious. I can do this.