What Are the Day Branch and Month Branch?
The day branch and month branch are the two core time markers used to score the strength of every line in a Liu Yao hexagram. The month branch (Yue Jian) is the earthly branch of the month the hexagram is cast in. The day branch (Ri Chen) is the earthly branch of the casting day. You see both on the line "Day Jia Zi · Month Yin · Hour Xu" shown above every hexagram you cast.
The classical text Zeng Shan Bu Yi calls the month branch "the framework of ten thousand hexagrams", the strength grid that governs all six lines for that entire month. The day branch adds a second, daily layer of effect: it can generate, overcome, combine with, or clash against any single line.
Why Does the Month Branch Set a Line Strength?
Every line carries an element through its na jia assignment. The month branch also carries an element, from its own earthly branch. Comparing the two elements produces one of five classical states:
| Line element vs month branch element | State | Meaning |
|---|---|---|
| Line shares the same element | Prosperous (Wang) | Strongest, in a favorable position |
| Month branch generates the line | Supported (Xiang) | Receiving support, rising |
| Line generates the month branch | Resting (Xiu) | Giving away strength, weakening |
| Line overcomes the month branch | Trapped (Qiu) | Still has force, but under pressure |
| Month branch overcomes the line | Dead (Si) | Weakest, needs support from another line |
Example: a line carrying the Metal element under a Yin (Wood) month branch. Metal overcomes Wood, so the line overcomes the month, putting it in the Trapped state, still with force but under pressure.
How Does the Day Branch Affect a Line?
Beyond scoring monthly strength, the day branch also checks a direct relationship with each line's own na jia branch: generating, overcoming, combining, or clashing. A line generated or combined by the day branch gets an immediate boost that day. A line clashed by the day branch becomes unstable, and the matter it represents tends to shift unexpectedly.
The day branch also determines the two void branches (Kong Wang) for that ten-day week, counted from the day's stem-branch pair. A line falling on a void branch temporarily loses effect, usually until the week that created the void has passed.
Does the Month Follow the Lunar Calendar or the Solar Term Calendar?
The solar term calendar, not the first day of the lunar month. The Yin month starts at the solar term Li Chun (Start of Spring), the Mao month starts at Jing Zhe, and every other month follows the same boundary from the 24 solar terms of the year. A hexagram cast late in the lunar twelfth month but after Li Chun already counts as month branch Yin, not the branch of the old lunar year.
The casting system on KinhDich.app computes the month branch from these exact solar term boundaries. When a cast falls close to a boundary, the time picker on the record screen warns that the month branch is about to change.
When Does the Day Branch Change?
The day branch changes exactly at 00:00 local time at the place where you cast, never at UTC or the server's own time. Casting at 23:50 and casting again at 00:10 the same night lands on two different day branches, only twenty minutes apart.
When casting while abroad, picking the exact time zone you are standing in is mandatory so the day branch does not shift. See casting I Ching abroad: which hour counts for how to pick the right time zone and hour branch far from Vietnam.
Does the Hour Branch Matter in Liu Yao?
Classical Liu Yao centers on two frameworks only: the day branch and the month branch. The hour branch (Zi hour, Chou hour...) is reference information, it does not enter the calculation of strength, void days, or generate-overcome relationships, unlike Four Pillars (Ba Zi) astrology, where the hour pillar is a full pillar of its own. KinhDich.app still displays the hour branch for reference, but it never changes the reading.
How Do the Day Branch, Month Branch, and Yong Shen Combine?
Identify the correct Yong Shen first, then read its condition against the month branch and day branch together. A Yong Shen that is prosperous by month but clashed by the day branch can still hit a short-term obstacle. Conversely, a Yong Shen weak by month but generated or combined by the day branch can partially recover.
No line is inherently "good" or "bad". Meaning always sits in the relationship between the line, the month branch, and the day branch at the same time.
A Worked Example: Reading Day and Month Branch on a Real Hexagram
Suppose you cast on day Jia Zi, month branch Yin (after Li Chun), hour Xu. The void branches for the Jia Zi week are Xu and Hai.
If your Yong Shen is a line carrying the Metal element: Metal overcomes Wood (month branch Yin), so the Yong Shen sits in the Trapped state, with force but under pressure. If this line's na jia branch is Wu, the day branch Zi clashes with Wu, adding further instability, and the reading needs support from other moving lines to hold steady.
The hour Xu in this example happens to match one of the two void branches (Xu), but that is a coincidence of display only. The hour branch does not itself place a line into void, as covered above.
Day and Month Branch on KinhDich.app
The record screen shows the full day stem-branch, month branch, and hour branch as soon as you pick a casting time. The time picker previews these values live and warns when the moment sits close to a solar term boundary, so you know the month branch is about to change before you save the cast.
If you are asking from abroad, read casting I Ching abroad: which hour counts to pick the right time zone before you cast a hexagram. To review the six-line structure first, see What Is Liu Yao (Six Lines).
Frequently Asked Questions
What are the day branch and month branch in Liu Yao?
The month branch is the earthly branch of the casting month, used to score the strength of all six lines through their elemental relationship to it. The day branch is the earthly branch of the casting day, checked against each line individually and used to determine that day two void branches.
What does the month branch decide for a line?
The month branch sets each line state as prosperous, supported, resting, trapped, or dead by comparing the line element to the month branch element. A line sharing the month branch element is prosperous and strongest, while a line overcome by the month branch is dead, the weakest state.
Where do the void branches (Kong Wang) come from?
Void branches come from the stem-branch pair of the casting day. Each ten-day week in the sixty-day cycle has exactly two branches with no matching stem, called that week void branches. The Jia Zi week has Xu and Hai as void. A line falling on either temporarily loses effect.
Does the Liu Yao month follow the lunar calendar or the solar term calendar?
It follows the solar term calendar, not the first day of the lunar month. The Yin month starts at Li Chun, the Mao month at Jing Zhe, and so on for all twelve months by the 24 solar terms, so the month branch can differ from the ordinary lunar month by several weeks.
Does the hour branch matter as much as the day and month branch?
No. Classical Liu Yao uses only two frameworks, the day branch and month branch, to score strength, void days, and elemental relationships. The hour branch is reference information and never changes the reading, unlike Four Pillars (Ba Zi) astrology where the hour pillar is a full pillar.
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