Five-Phase Mutual-Inclusion Model: Refining Constitution and Medicinal Essence

When diseases and pathomechanisms encountered in the clinic become extremely intricate, a coarse Five-Phase division—choosing one category out of five—can become inadequate. To increase diagnostic and therapeutic precision, the ancients developed the Five-Phase mutual-inclusion model. Its essential move is to let the Five-Phase system operate upon itself again, like a matrix multiplication, expanding the system into 5 × 5 = 25 more microscopic and more precise energetic attributes. This yields finer distinctions such as “Wood within Wood,” “Fire within Wood,” or “Metal within Earth.” It is comparable to increasing feature resolution in machine learning: although diagnosis becomes more difficult, because the task shifts from choosing among five categories to choosing among twenty-five, the potential clinical resolution also increases greatly.

Mutual inclusion subdivides the Five Phases again, giving constitution, voice, medicinal essence, and other attributes a finer resolution.

The diagram of the twenty-five medicinal essences shows a practical application of Five-Phase mutual inclusion to fine-grained classification of materia medica.

Comparing classical texts and teaching examples

Two major applications of this model appear in classical and derivative texts. The first is the “Twenty-Five Types of Yin and Yang” chapter of the Lingshu, where human constitutions are divided into twenty-five Five-Phase mutual-inclusion types and assigned corresponding standard five tones and derivative tones as a basis for acoustic and time-selective regulation. The second is the Diagram of the Twenty-Five Medicinal Essences recorded in the Fuxing Jue.