Though Yi Hwang (Toegye) and Yi I (Yulgok) are two contemporary
philosophers, because of their different thought styles, they became
prime movers for two opposite schools in the Korean history of
philosophy: Yeongnam School and Kiho School. Hence, even though
they are both great scholars of Neo‐Confucianism, in ontology area, Yi
Hwang placed emphasis on the I as the existential force that
determines gi, while Yi I placed emphasis on gi rather than I. In
Temperament theory area, Yi Hwang emphasized I‐Gi‐interaction
theory, while Yi I emphasized I‐Gi‐coaction theory. In Practical
Theory, Yi Hwang focused on respect, while Yi I focused on sincerity.
Differences of thought styles of these two philosophers as listed before
have been extensively studied and have been considered as being fixed.
This study looked through specific differences between Yi Hwang’s The
Ten Diagrams on Sage Learning and Yi I’s The Essentials of the Studies
of the Sages based on the results of previous research to see their
philosophical characteristics and contributions to Confucian history of