Wu Xing (Calendar System)

The theory of the five phases — Wu Xing (五行, "five movements" or "five phases") — is one of the foundational ontological frameworks of Chinese civilization.

Not substances, but phases. Unlike the Western four elements, Wu Xing describes not substances, but processes — phases of energy transformation, constantly transitioning into one another.

Origins. The theory took shape during the Warring States period (5th–3rd centuries BCE) and became the basis of all Chinese metaphysics, medicine, and natural philosophy.

Five Elements and Two Cycles

Wood, Fire, Earth, Metal, Water linked by two cycles.

The Generation Cycle (相生, xiang sheng)

• Wood → Fire (it burns)
• Fire → Earth (ash)
• Earth → Metal (from its depths)
• Metal → Water (condensation)
• Water → Wood (growth)

The Overcoming Cycle (相克, xiang ke)

• Wood overcomes Earth
• Earth absorbs Water
• Water extinguishes Fire
• Fire melts Metal
• Metal chops Wood

Calendrical Application

Tied to time. Each year, month, day, and hour receives an elemental and stem-branch designation.

Stems and branches. The 10 Heavenly Stems (Tiangan) carry each element in pairs — in yin and yang polarities. The 12 Earthly Branches (Dizhi) carry hidden stems within them.

The foundation of Ba Zi. This creates the foundation for Chinese chronology and astrological systems — primarily Ba Zi (#10), which uses Wu Xing as its main interpretive matrix.

Place in Errarium

Calendrical vs medical. In Errarium, Wu Xing in its calendrical application is treated separately from its medical application (#25): the same theoretical foundation, but different domains and instruments.

A unique ontology. The closest analogues by function are Western astrology (#1) and Tibetan elemental astrology (#39); in terms of ontology, it is a unique structure with no direct counterparts in other traditions.