The Essentials of the Learning of the Sages (Seonghak jibyo)

A Neo-Confucian handbook compiled by Yi I, known as Yulgok, and presented in 1575 to the young King Seonjo of Joseon. Its aim is to educate a ruler in the learning of the sages. Yulgok gathers passages from the Confucian classics and the Song masters, adds his own comments, and arranges them on the plan of the Great Learning, which links personal cultivation to good government. After an opening general statement, the long chapter on cultivating oneself covers setting one's will, investigating principle, sincerity, reforming one's temperament, nourishing vital energy and rectifying the mind. Further chapters treat regulating the household and the way of governing, including the choice of worthy ministers and care for the people. A last chapter traces the transmission of the Way from the ancient sages down to Zhu Xi. Yulgok meant it as a more concise and practical alternative to Zhen Dexiu's much longer Extended Meaning of the Great Learning, an older handbook on the same plan.

It shows how Korean Neo-Confucians tied a ruler's inner moral life to the health of the state, a link between personal ethics and politics that is still argued over.