The Eight Trigrams (Ba Gua): I Ching Building Blocks

In the patterns below, read the digits from bottom to top: 1 is an unbroken yang line and 0 is a broken yin line. Three positions with two possibilities give eight patterns.

The natural images are discussed in the Shuo Gua commentary. Directional layouts add another convention, so the order of this reference is not a room-layout map.

Worked comparison: Hexagram 63, After Completion, places Water (Kan) above Fire (Li). Reversing those trigrams gives Hexagram 64, Before Completion. Check both positions; the same two images can form different figures.

A trigram is a stack of three yin or yang lines. There are eight possible combinations, giving eight trigrams. Each trigram has a name, a natural image, a direction, a family role, and a set of associated qualities. The eight trigrams are: Qian (Heaven), Kun (Earth), Zhen (Thunder), Xun (Wind), Kan (Water), Li (Fire), Gen (Mountain), and Dui (Lake).

Two trigrams stacked together form a hexagram. The lower trigram is called the inner trigram and often describes the internal situation or the person asking. The upper trigram is the outer trigram and often describes the external environment or the situation being faced.

Each trigram carries a cluster of associations. Qian (three solid yang lines) is associated with Heaven, strength, the father, and creative force. Kun (three broken yin lines) is associated with Earth, receptivity, the mother, and yielding support. Kan (broken-solid-broken) is associated with Water, danger, the middle son, and depth. Li (solid-broken-solid) is associated with Fire, clarity, the middle daughter, and attachment.

These associations are not rigid personality labels. They describe qualities of movement and relationship. A hexagram with Li below and Kan above (Hexagram 63, Ji Ji) describes a situation where water and fire are in their correct positions — a moment of completion that still requires care to maintain.

The eight trigrams are arranged in two classical sequences: the Earlier Heaven (Fu Xi) arrangement and the Later Heaven (King Wen) arrangement. The Later Heaven arrangement is used in most practical applications, including Feng Shui Bagua mapping. Understanding the trigrams is the foundation for reading hexagram structure, since every hexagram is a combination of two trigrams.