Many people new to Plum Blossom Numerology (Meihua Yishu) encounter the phrase "ti-yong sheng ke" (the generation and conquest relationship between the body hexagram and the use hexagram) and immediately assume: if the yong hexagram generates the ti hexagram, things will go well; if the yong hexagram conquers the ti hexagram, things will go badly. That instinct points in roughly the right direction, but it only covers half the picture. Whether sheng or ke spells good or bad fortune depends on the strength and weakness of the ti and yong hexagrams and on how the hexagram transforms — none of it is fixed in advance.
How Ti and Yong Are Determined
After casting a hexagram, the six lines divide into two three-line trigrams: the upper trigram and the lower trigram. Whichever side the querent falls on becomes the ti hexagram (body hexagram); the side representing the other party, the matter at hand, or the goal becomes the yong hexagram (use hexagram).
How exactly is this determined? The most widely used folk method looks at which trigram contains the moving line (the changing line, or bian yao). The trigram that holds the moving line becomes the yong hexagram; the other becomes the ti hexagram. Cases with no moving line are rarer, and different schools handle them differently — some take the upper trigram as yong, others assign it based on the nature of the question. This essay will not go into those variations.
The ti hexagram represents the querent; the yong hexagram represents the matter being asked about or the other party involved. Assessing good and bad fortune centers on the sheng ke relationship between these two trigrams and on the relative strength or weakness of each.
What Each of the Four Sheng-Ke Situations Means
Yong generates ti: The yong hexagram supports the ti hexagram — favorable to the querent. Ask about wealth and money comes to support you; ask about a job and the other party is willing to take you in; ask about illness and outside forces aid your recovery. This is the most clearly auspicious of the four situations.
There is one caveat, though: the ti hexagram must not be excessively strong. In Five Elements (Wu Xing) theory, when something has reached an extreme it reverses — if the ti hexagram is already at peak strength, receiving more generation becomes a burden rather than a blessing. The tradition calls this "wang bu shou sheng" (the extremely strong do not receive generation well), and in such cases the auspicious quality is diminished.
Ti generates yong: The ti hexagram feeds the yong hexagram — the querent must expend and give. Ask about finances and money flows out; ask about a partnership and you are subsidizing the other side; ask about illness and your vitality is being consumed. This generally leans inauspicious, but how inauspicious depends on whether the ti hexagram is strong or weak. A strong ti hexagram can afford to give; a weak ti hexagram draining outward into yong spells real trouble.
Yong conquers ti: The yong hexagram suppresses the ti hexagram — unfavorable to the querent. This is one of the most common ominous signs. Even so, yong conquering ti does not mean the matter is entirely hopeless; it more precisely signals "obstacles, pressure, and possible harm." The severity still hinges on strength and weakness — a strong ti hexagram can withstand conquest without collapsing; a weak and exhausted ti hexagram, when conquered, faces genuine danger.
Ti conquers yong: The ti hexagram suppresses the yong hexagram — the querent holds the initiative. Ask about litigation and conditions favor you; ask about competition and you can outpace your opponent; ask about illness and righteous qi is subduing the pathogenic force. This leans auspicious. But here too there is a reversal: if the ti hexagram is itself extremely depleted, attempting to conquer the yong may fail, leaving you vulnerable to a counterattack.
Among these four, "yong generates ti" and "ti conquers yong" lean auspicious; "ti generates yong" and "yong conquers ti" lean inauspicious — that is the basic framework. But to be clear: this framework is a starting point, not a conclusion.
Strength and Weakness Is the Real Lever
Shao Yong's Plum Blossom Numerology (Meihua Yishu) repeatedly stresses that before interpreting any hexagram, you must first assess the strength (wang shuai) of the ti hexagram. How? Match the Five Elements (Wu Xing) phase of the ti trigram against the month and day of casting.
For example, if the ti hexagram is Zhen (属木, Wood), and the hexagram is cast in spring (Yin or Mao month, when Wood is dominant), the ti hexagram is strong and flourishing. Cast in autumn (Shen or You month, when Metal conquers Wood), the ti hexagram enters a state of rest and weakness (xiu xiu). Against the same "yong conquers ti" configuration, a flourishing ti hexagram can hold its ground; a depleted ti hexagram faces serious peril.
The parallel in everyday life is intuitive: a strong, healthy person enduring an external blow and an already-weakened person enduring the same blow do not face the same outcome at all.
So "generation means auspicious, conquest means inauspicious" is not wrong — it is just incomplete. Without assessing strength and weakness, sheng and ke are only half the information.
What the Nuclear Hexagram and Changing Hexagram Add
Two further layers are often overlooked by beginners: the hu gua (nuclear hexagram) and the bian gua (changing hexagram).
The nuclear hexagram is constructed by taking lines two, three, and four of the original hexagram to form the lower nuclear trigram, and lines three, four, and five to form the upper nuclear trigram, yielding a new hexagram. It represents the middle stage of the matter — a supplement to the original ti-yong relationship. Sometimes the initial ti-yong relationship looks favorable, but a Five Element phase that conquers the ti hexagram appears inside the nuclear hexagram, signaling turbulence along the way.
The changing hexagram is the new hexagram formed after the moving line transforms. It represents the ultimate direction the matter is heading. Some situations start with yong conquering ti — looking grim — yet the changing hexagram shows the ti hexagram growing strong, or the generation-conquest relationship reversing, and the outcome may not be bad after all. Conversely, a situation that begins with yong generating ti can turn treacherous if the changing hexagram shows the ti hexagram entering a state of "mu" (entombment) or "jue" (extinction).
The traditional reading method is: the original hexagram reveals the present state; the nuclear hexagram reveals the process; the changing hexagram reveals the outcome. Only by synthesizing all three layers is the reading complete. Fixing your attention solely on the sheng ke of the original hexagram is a common source of mistaken judgments.
One Point That Often Causes Confusion
Some ask: since the yong hexagram represents the other party, does "yong conquers ti" always mean the other party is suppressing me, and "ti conquers yong" always mean I am suppressing the other party — and does this logic apply universally to every type of question?
In most cases, yes. But one category of question requires care: illness. The querent's body is the ti; the pathogenic force is the yong. "Yong conquers ti" means the pathogen is invading the body — inauspicious. "Ti conquers yong" means righteous qi is subduing the pathogen — auspicious. That logic holds. But if the question is "I am helping someone else — can they recover?" then the assignment of ti and yong must be redefined from scratch, and you cannot apply the same framework as if asking about yourself.
The key is to think clearly before casting: what does the ti hexagram represent, and what does the yong hexagram represent? Once that is settled, the meaning of each sheng ke verdict falls into place. Without that clarity, even thorough mastery of the generation-conquest rules will lead you nowhere.
Articles in this column are for cultural and educational purposes only and do not constitute life advice.