The book of Sa So Jeol is about the moral training family precepts written by Yi Deok-mu (이덕무, 1739~1793) in the year of king Young Jo 51th in the Yi dynasty. The writer provides us, according to the views of Confucianists, with the principles that both elders and children of that time should abide by in the daily life, dividing the said books into 924 sections, 8 chapters, and 2 volumes. The parts concerned with children are studied in this essay. The brief conclusions are as follows. 1. Children were required to have the mental attitudes of honesty, patience, tolerance and frugality and were instructed to show such attitudes through their behavior. 2. Children were instructed to have the behavioral attitudes of nine aspects, which are the behavioral characteristics of the sages. They were instructed to emulate the personal characters of the sages through being possessed of these nine aspects, which are to be found in healthy and comfortable mental states. 3. Children were instructed to be careful and composed, in their activities. Since prudence is the basic principle of mental and behavioral attitudes, being required of men and women of all ages in a traditional society, it was emphasized from early childhood 4. The aim of instruction was taken to be becoming human, or becoming a virtuous man, rather than merely passing the classical government examamination, and for this aim the moral rules, which can be considered the order of human relations, were taught intensively. 5. As for instructional methods, the children were required to do careful or rough reading according to their abilities, and were instructed to listen to lectures politely, prudently, ardently and honestly. 6. The instructional contents are for the purpose of making children read the classical canons after increasing their perceptive ability in the various things of the sexagenary cycle, the multipicative method, the kings, lineage, and the reign-titles, and the accumulated knowledge of $ulcorner$Kyung Mong Yo Kyul$lrcorner$, $ulcorner$Seong Hak Jeop Yo$lrcorner$ and $ulcorner$Keun Sa Lok$lrcorner$. Because of the greater emphasis on natural talents rather than on acquired abilities, the children, however, were eudcated only after their despositions were examined. 7. The children were required to have warm-hearted, careful, polite, and prudent attitudes toward their elders, and were instructed to take precauticns against arrogance and impoliteness. Since politeness in particular was considered not only as the ground of decorum but the method of emotional regulation and maintaining composure for confucianists, it can be regarded as the principal ettiquettee demanded in all activities. 8. The main instructional contents are generally moral aspects, concentrating on introspection and virtuous conduct through emotional regulations, rather than on the natural expression of physical and mental states.