Through reinvestigations of early years of King Young-Joe provincial castles, Jeonju Eupsung, this study seeks to broaden the understanding of castle construction of the later period of Chosun Dynasty. Jeonju Eupsung was established by reform-minded king and his loyalist Cho, Hyun Myung. Their new conceptual framework for reconstruction of Jeonju Eupsung was affected by Yoo, Hyung Won, a realist scholar of 17th century. It is obvious that adopted new administrative systems of financing, building and maintaining of Jeonju Eupsung were based on the his theories of castle. This study demonstrates that Jeonju Eupsung built by Cho, Hyun Myung, during the early years of King Young-Joe were based on those new concepts and systems of the new age. The study shows that the designer of this castle had in mind efficient construction design and execution and effective defense of provincial towns located on flat ground. And, the study explains how those original designer sought higher productivity through greater localization of securing resources and more detailed and improved organization of construction responsibilities. In short, this study seeks to prove that the provincial castles of the early 18th century reflected the new thinking on practicality that was spreading throughout the society of Chosun Dynasty at the time.