The Sui Dynasty continued the explorations of the Northern and Southern Dynasties, working to organize and standardize theory. Xiao Ji wrote the Great Meaning of the Five Elements, systematically organizing Five Elements theory since the Han and Wei. Lu Cai critiqued and organized the chaotic destiny texts of his time, separating truth from falsehood. This period's work cleared theoretical obstacles for Li Xuzhong to establish the complete ancient model in the Tang Dynasty.
581 – 618 CE
Theoretical Systematization

Masters & Contributions
Xiao Ji
Key Works
Great Meaning of the Five Elements
Historical Contribution
Sui Dynasty synthesizer who systematically discussed Five Elements interaction, bridging Han theory with later destiny analysis.
Lu Cai
Key Works
Preface to Destiny Analysis
Historical Contribution
Organized and critiqued popular destiny texts, separating fact from fiction and reflecting early Tang's flourishing interest.