This book suggests awareness of issue that study of Tasan(茶山) was so irrational and tried to have only theoretical approach. 易理四法 was analysis system of Chuyŏk(周易) of Tasan(茶山 consisted of our frameworks and through this,study progressed being taken attention of academia at that time. However,study have done so far focused on closed and completed explaining about 易理四法 in respectively rather than opened and connected. This book has purpose of promoting ways which is fit for study of Yŏgiron(易理論) of Tasan and overcoming the limits of imperfect due to driven theory by separate practical association.