What Is the Corresponding Line in Six Lines I Ching Divination?

Understanding 应爻 (ying yao) and the host line in Na Jia

In Six Lines I Ching divination (Liu Yao, Wen Wang Gua, Na Jia), two technical terms appear again and again:

• Host line/ho (世爻, shi yao)
• Corresponding line/co (应爻, ying yao)

Most introductory books say something like:

• the host line represents “me”, the querent or main side
• the corresponding line represents “the other side”, the counterpart

This is a useful shortcut, but it does not explain where the idea of the corresponding line comes from, or why it is so central in Na Jia practice.

In this article for I Ching Stream, we will look at:

1. The internal geometry of a hexagram
2. The classical origin of “response” 应 in early I Ching literature
3. How Na Jia adds the host line on top of this structure
4. How to read the corresponding line in real Six Lines divination

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1. The hidden geometry inside every hexagram

A hexagram has six lines, but these six lines are not just stacked randomly. They have a very simple internal pairing:

• Line 1 corresponds to line 4
• Line 2 corresponds to line 5
• Line 3 corresponds to line 6 (the top line)

You can picture the hexagram as two three-line trigrams:

• the lower trigram (lines 1, 2, 3)
• the upper trigram (lines 4, 5, 6)

Inside this structure, each line in the lower trigram has a partner in the upper trigram that stands exactly three steps away:

• bottom below ↔ bottom above (1 ↔ 4)
• middle below ↔ middle above (2 ↔ 5)
• top below ↔ top above (3 ↔ 6)

This 1–4, 2–5, 3–6 pairing is the basic skeleton for what later Na Jia calls the corresponding line.

So in a purely structural sense:

Every line in a Six Lines hexagram has a corresponding line.

1 with 4, 2 with 5, 3 with 6.

This is already one reason why “corresponding line” is a good English translation. It is literally the line that corresponds to another line in this built in pattern.

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2. Classical background: where 应爻 (“responding line”) comes from

The term 应爻 (ying yao) did not come from modern Na Jia manuals. It grows out of an older cosmology of resonance between Heaven and Earth.

Early Han dynasty texts linked events in different layers of the cosmos with the idea that:

when something moves in one layer, another layer quietly answers it.

One line in the apocryphal Yi literature (《易纬 · 乾凿度》Yi Wei, Qian Zao Du) is often summarized as:

• when movement happens below the earth, there is a response below Heaven
• when movement happens in the middle of the earth, there is a response in the middle of Heaven
• when movement happens above the earth, there is a response above Heaven

Later exegetes mapped this world view onto the six lines of a hexagram:

• the lower three lines are like earth or “below”
• the upper three lines are like Heaven or “above”

Under this view:

• line 1 below responds to line 4 above
• line 2 below responds to line 5 above
• line 3 below responds to line 6 above

These three pairs became the corresponding lines, 应爻.

The character 应 means:

• to answer
• to respond
• to match or correspond to something

So 应爻 literally means:

the line that answers another line,
the line that stands opposite and responds to it.

Traditional commentaries often say things like:

• when the corresponding line responds, take the meaning from that response
• when there is no response, take the meaning from the lack of response
• when there is no response, there is no gain

In other words, classical I Ching diviners were not only looking at one line in isolation. They were looking at a pair inside the hexagram and asking:

• does the other side answer
• is there a real resonance
• or is one side active while the other side remains closed

This is the classical heart of the corresponding line: a way to read resonance, support, or silence along the 1–4, 2–5, 3–6 axes.

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3. A concrete example: when the pair fails to respond

A famous example appears in commentaries on the hexagram Gui Mei (Returning Maiden). One explanation notes:

• the top line is a yin line
• the third line is also a yin line
• the top line moves, but the third line does not move

By the old rule, a true “response” often prefers one yin facing one yang, or at least some sign that the two sides actively engage each other. Two yin lines of the same polarity, with only one side moving, are read as not in response (bu ying).

Practically, this means:

• there is a main actor or main line that tries to move
• the partner that should answer it is closed, passive, or simply not engaging
• the relationship has no real support behind it

The commentary links this to the historical story attached to Gui Mei. Someone reaches out for alliance and help, but the hoped for counterpart does not truly answer. On the divinatory level this becomes an image of disappointment and lack of gain.

This is exactly how classical 应爻 works:

The corresponding line is not just “the line on the other side”.
It tells you whether the other side really responds.

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4. How Na Jia adds the host line (世爻) on top

So far, we have only talked about pairs inside the hexagram. This already gives three sets of corresponding lines in every I Ching figure.

Na Jia adds another key concept that you will see on almost every Six Lines divination chart: the host line, 世爻.

In a real reading, we usually do not treat all six lines as equal. We choose one line to be the center of the story. This line is the host and often represents:

• the querent
• our side
• the main situation that we care about

Once we select a host line, the 1–4, 2–5, 3–6 structure immediately tells us which line is especially important:

• if the host line is on line 1, its partner is line 4
• if the host line is on line 2, its partner is line 5
• if the host line is on line 3, its partner is the top line
• if the host line is on line 4, its partner is line 1, and so on

This partner is what Na Jia calls the corresponding line in everyday practice:

the line that corresponds to the host line,
the line that answers, supports, opposes, or ignores the host.

So in Na Jia manuals and Six Lines charts you often see a simple pair of labels:

• 世 = host line
• 应 = corresponding line

People talk as if there is only one corresponding line in the hexagram. What is happening in the background is:

• structurally, each line still has its corresponding partner
• methodologically, we focus on the line that corresponds to the host line
• because that pair tells the core story of “me and the other side”

In short:

host line = “me, our side, the main party”
corresponding line = “the counterpart, the other side, what answers me”

This is why the 世–应 axis sits at the center of many Na Jia readings.

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5. How to read the corresponding line in Six Lines divination

Once you understand both layers, the geometry and the classical idea of response, you can start to read the corresponding line more confidently in your own I Ching divination.

Here are a few practical questions that Na Jia readers often ask:

5.1 Is there a real response at all?

Sometimes the structure, polarity, or movement leads commentators to say that the pair is “not responding”.

This often points to situations where:

• there is no real partner
• the other side is there in name only
• there is no true support behind the apparent promise

In relationship readings, this can mean unreturned feelings.
In business readings, it can mean empty offers or contacts that do not follow through.

5.2 Who is stronger, the host line or the corresponding line?

Using the Five Elements, seasonal strength, and other Na Jia tools, you can see:

• if the corresponding line is stronger and overcomes the host, the other side may control, pressure, or restrict the querent
• if the host line is stronger, the querent has more initiative and leverage

This is one reason Six Lines divination feels so “strategic” to many practitioners. The host line and corresponding line show not only whether someone responds, but also who is really in a position of power.

5.3 Do they generate, overcome, or simply stand together?

Looking at the elemental relationship between the host line and its corresponding line:

• generation suggests help, support, nourishment
• overcoming suggests conflict, control, or obstacles
• same element can suggest alignment, competition, or mutual reinforcement, depending on context

This single pair can already tell you a great deal about whether a relationship, contract, or plan is likely to be cooperative or tense.

5.4 Is the corresponding line moving or static?

Movement is also important:

• a moving corresponding line often means the other side is active, changing, unstable, or in the middle of making decisions
• a static corresponding line is quieter; it can indicate reliability or indifference, depending on its strength and position

Again, the key question is:

Is the other side really answering the host line, and how?

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6. Summary: why “corresponding line” is exactly the right name

We can now bring everything together into one simple definition.

The corresponding line (应爻, ying yao) in Six Lines I Ching divination is:

• the line that stands opposite another line in the hexagram
• the line that answers it according to the 1–4, 2–5, 3–6 pattern
• and in Na Jia practice, especially
• the line that corresponds to the host line, showing “the other side” of the story

Structurally, every line has a corresponding line.
In Na Jia readings, we focus on the corresponding line of the host, because that is where the main relationship, negotiation, or tension unfolds.

So each time you cast a hexagram with Six Lines divination, you can quietly ask:

• Who is the host line in this question
• Which line is its corresponding line
• Does that line truly respond
• Is it helping, blocking, or staying silent

This is the real function of the corresponding line. It turns the hexagram from a static picture into a living dialogue between “me and the other side”.

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If you want to go deeper into Six Lines divination, Na Jia methods, and classical case studies, I Ching Stream offers English editions of core I Ching divination texts, plus tools and courses designed for non-Chinese readers.