During this course, a strict system of clinical modification will be taught. The system was developed by Dr. Versluys over the course of the last ten years by analyzing both Zhang Zhongjing’s prescriptions as well as the characteristics of the Tian-Zeng lineage’s clinical practice. It is fully grounded and based in the classical writings of the original designer of the formulas, Zhang Zhongjing. The system is organized along a hierarchical system of formula modifications and provides a failsafe method for modification to adapt to a broader collection of complex clinical manifestations as often encountered in Chinese medicine clinic in the West. A waterproof modification system forms the basis of classical herbal practice and the elimination of random clinical variables which are the greatest cause for failure in clinic.