I. Foundations

Part 3: Eight Trigrams (Bagua)

3.4. Yao (Lines), Yin and Yang, and How to Count Line Positions

Everything else, trigrams, hexagrams, changing/active lines, and line texts, is built on top of it. This post lays out the essentials of I Ching Divination in a clean, practical way for English-language readers worldwide.

1. What is a yao (line)?

A yao is a single line in an I Ching diagram. There are only two kinds:

• Yang line (solid line), traditionally associated with strength, clarity, initiative
• Yin line (split line), traditionally associated with receptivity, yielding, consolidation

These lines combine into larger structures.

2. Trigrams and hexagrams are line structures

In classical I Ching structure:

• The eight trigrams (also called the eight basic trigrams, or bagua) are each made of three lines.
• The sixty-four hexagrams are each made of six lines.

3. Yin and yang lines are also called “six” and “nine”

Traditionally, the I Ching uses number-names for the two line types:

• Yang line is also called nine
• Yin line is also called six

It is a shorthand for the line’s yin or yang quality within the classical naming system.

4. How to count the line positions

 You count from the bottom upward.

For a six-line hexagram:

• Top line (at the top), also called the upper line
• Fifth line
• Fourth line
• Third line
• Second line
• First line (at the bottom), also called the initial line

5. The two special cases: Use-Nine and Use-Six

• Use-Nine is associated with a fully yang context (classically tied to Qian)
• Use-Six is associated with a fully yin context (classically tied to Kun)

These are not “extra lines” you stack onto the hexagram. They are a special kind of judgment line used in a complete yang or complete yin situation.

6. Why line texts matter in divination practice

In practical reading, the line position is not decoration, it is structure.

• The lower lines often describe beginnings, foundations, early signals.
• The middle lines often show development, pressure, decisions, and positioning.
• The upper lines often indicate culmination, excess, resolution, or reversal.

Below are two canonical sequences you can use as reference anchors, one for the full yin set (Kun), one for the full yang set (Qian).

Reference examples (line texts and translations)

Qian (The Creative / Heaven) – Heaven over Heaven: Origin and Smoothness. Benefit (or Advantage) and Constancy.

乾：元亨利贞。

· Interpretation: From the very beginning, everything proceeds smoothly. When used for divination, it will yield auspicious results.

· The Tuan Commentary says: Great indeed is the Origin of Qian! All things derive their beginning from it; and so it rules over Heaven. The clouds move and the rain is bestowed, the various things flow into their forms. Greatly illuminating the end and the beginning, the six positions are completed in time. In time, one mounts the six loongs to drive across the heavens. The Way of Qian changes and transforms, allowing each thing to find its correct nature and destiny. Preserving the union of the Great Harmony brings about Benefit and Constancy. It stands at the head of all things, and all nations enjoy peace.

· The Xiang Commentary says: Heaven’s movement is powerful. Thus the noble one strengthens himself without ceasing.

Use-Nine: A flight of headless (leaderless) loongs appears; auspicious.
用九：见群龙无首。吉。
• Interpretation: A group of loongs appears in the sky. They are flying gracefully, with their heads hidden in the clouds. This is a sign of good fortune.
• The Xiang Commentary says: The virtue of Heaven is not to act as the head.

Top-Nine: Arrogant loong will have regret.
上九：亢龙有悔。
• Interpretation: A loong flies to the highest point. It is apparent that it will encounter disaster.
• The Xiang Commentary says: “Arrogant loong will have regret,” for what is full cannot last long.

Nine-Five: Flying loong in the heavens. Benefit in meeting great persons.
九五：飞龙在天。利见大人。
• Interpretation: A loong soars in the sky.
• The Xiang Commentary says: “Flying loong in the heavens,” the great person is at his creative work.

Nine-Four: Wavering in the abyss. No errors.
九四：或跃在渊。无咎。
• Interpretation: Some loongs dive underwater to hide.
• The Xiang Commentary says: “Wavering in the abyss,” to advance brings no errors.

Nine-Three: The noble one is creative and active all day, vigilant and apprehensive at night. Danger, no errors.
九三：君子终日乾乾，夕惕若。厉，无咎。
• Interpretation: Noble and virtuous individuals strive diligently throughout the day and remain cautious even at dusk.
• The Xiang Commentary says: “Active all day,” this is to travel the Way again and again.

Nine-Two: Seeing loong in the fields. Benefit in meeting great persons.
九二：见龙在田。利见大人。
• Interpretation: A loong appears in the fields.
• The Xiang Commentary says: “Seeing loong in the fields,” for the influence of virtue is widespread.

First-Nine: Hidden loong, do not use.
初九：潜龙，勿用。
• Interpretation: A loong remains in a latent state.
• The Xiang Commentary says: “Hidden loong, do not use,” because the yang energy is still below.

Kun ䷁ sequence (all Six lines, plus Use-Six)

Kun (The Receptive / Earth) – Earth over Earth: Origin and Smoothness. Benefit or Advantage of a mare’s Constancy. The noble one has a direction to go, first gets lost, then finds the master. Benefit or Advantage. In the southwest find friends, in the northeast lose friends. Peaceful Constancy, auspicious.

坤：元亨。利牝马之贞。君子有攸往，先迷后得主。利。西南得朋，东北丧朋。安贞，吉。

• Interpretation: From the very beginning, everything proceeds smoothly. When used for divination regarding a mare, it will yield auspicious results. Noble and virtuous individuals may initially feel lost when seeking a political position, but they will eventually find a trusted leader. This is a fortunate outcome. If you make new friends in the southwest but lose old friends in the northeast, remain calm and consult the divination; the result will be favorable.

• The Tuan Commentary says: Ultimate indeed is the Origin of Kun! All things derive their life from it, as it follows and receives from Heaven. Kun, in its thickness, carries all things; its virtue matches the boundless. It contains the vast and illuminates the great; the various things all attain smoothness. The mare belongs to the category of Earth; it travels the earth without boundaries, gentle, compliant, with Benefit and Constancy. When the noble one acts, at first he may get lost and miss the Way, but later, by being compliant, he finds the constant principle. He finds friends in the southwest, and thus walks with his own kind; he loses friends in the northeast, but in the end there is cause for celebration. The auspiciousness of peaceful Constancy comes from corresponding with the boundless nature of the Earth.

• The Xiang Commentary says: The Earth’s condition is Kun. Thus the noble one, with his profound virtue, supports all things.

Use-Six: Benefit or Advantage in perpetual Constancy.
用六：利永贞。
• Interpretation: Always consult divination before taking action; doing so will lead to auspicious results.
• The Xiang Commentary says: “Perpetual Constancy in the Use-Six line,” so that the conclusion may be great.

Top-Six: Loongs fighting in the wilds. Their blood is black and yellow.
上六：龙战于野。其血玄黄。
• Interpretation: Loongs in the field are fighting fiercely, and their blood is dark yellow in color.
• The Xiang Commentary says: “Loongs fighting in the wilds,” its way has come to an end.

Six-Five: A yellow lower garment. Origin auspiciousness.
六五：黄裳。元吉。
• Interpretation: Yellow garments symbolize fortune and prosperity from the very beginning.
• The Xiang Commentary says: “A yellow lower garment; Origin auspiciousness,” for the pattern is on the inside.

Six-Four: A tied-up sack. No errors, no praise.
六四：括囊。无咎，无誉。
• Interpretation: If your situation resembles a tied-up sack with no outlet, you will neither make mistakes nor gain any honor.
• The Xiang Commentary says: “A tied-up sack; no errors,” through caution, one avoids harm.

Six-Three: Hidden brilliance, able to be constant.
六三：含章，可贞。或从王事，无成，有终。
• Interpretation: If you are someone skilled in self-expression, you may use this talent to inquire about your future. Alternatively, serving the king, though unlikely to bring great accomplishments, will lead to a good outcome later.
• The Xiang Commentary says: “Hidden brilliance, able to be constant,” is to be revealed in its own time. “If in the service of a king,” one’s wisdom is brilliant and great.

Six-Two: Straight, square, great. Without purpose, yet nothing is not of Benefit or Advantage.
六二：直，方，大。不习，无不利。
• Interpretation: Being overly straightforward, rigid, or arrogant, if you avoid these three habits, nothing in the world will be inauspicious for you.
• The Xiang Commentary says: “The movement of the six in the second place” is straight and square. “Without purpose, yet nothing is not of Benefit or Advantage,” for the Way of the Earth is brilliant.

First-Six: Treading on frost, solid ice is coming.
初六：履霜，坚冰至。
• Interpretation: When you step on frost, thick ice will soon follow.
• The Xiang Commentary says: “Treading on frost, solid ice is coming,” for the yin begins to congeal.