Mei Hua Yi Shu Calculator
Mei Hua Yi Shu is traditionally attributed to Shao Yong. What sets it apart is how freely it casts: a time, a spoken number, a direction or something noticed in passing will all serve. It attaches no stems and no relatives, reading the trigrams directly. This page covers casting through to the subject and object.
The Earlier Heaven numbers
Casting uses the Earlier Heaven sequence, which assigns a number from one to eight to each of the eight trigrams. Any number reduced into that range yields a trigram. This sequence comes from the Earlier Heaven arrangement and is not the same as the numbers attached to the Later Heaven arrangement; mixing the two produces an entirely different hexagram.
Converting anything at all into a number, and the number into a trigram, is what makes this system so flexible. A number spoken aloud, a sound heard, an object seen, a direction faced — anything that yields a number will cast.
Casting from a time
The common method casts from the moment itself. The year, month and day numbers are summed and reduced by eight for the upper trigram; the hour is added and the sum reduced by eight for the lower; the full sum reduced by six gives the moving line. Where a remainder would be zero, the divisor is used instead.
The year and hour are taken as branch ordinals and the month and day from the lunisolar calendar. Which calendar applies matters: this is not the solar-term calendar that BaZi uses, so a cast and a birth chart taken from the same instant are not reading the same numbers.
Original, nuclear and changed
The hexagram as cast is the original, standing for the matter as it is. Lines two through four and three through five form the two trigrams of the nuclear hexagram, standing for the middle of the process. The moving line changes to produce the changed hexagram, standing for where the matter is heading. Read together, the three give a line from present state to outcome.
The nuclear hexagram is drawn only from lines two through five; the bottom and top lines take no part. This is fixed convention, not a shortcut.
Subject, object and the elemental relation
The hexagram divides into an upper and a lower trigram. The one containing the moving line is the object, standing for the matter asked about; the other is the subject, standing for the querent. The reading rests on the generating and controlling relation between these two trigrams.
The nuclear and changed hexagrams are read against the subject in the same way, giving the middle and the end of the matter. Mei Hua is less rule-bound than Liu Yao and leans more on understanding the images themselves, which is why the classical treatise on trigram imagery is required reading here.
How it differs from Liu Yao
Both produce a six-line hexagram, but they treat it in completely different ways. Liu Yao attaches stems and branches, assigns the Six Relatives and Six Spirits, marks the subject and object lines and void branches, and then selects a useful god. Mei Hua attaches nothing and reads the trigram images and their elemental relation directly.
That difference decides where each is used. Liu Yao narrows a matter down to one clearly identified line, which suits a question about whether something will come about. Mei Hua casts on whatever presents itself and does not require the question to be fully formed.
How to use it
- Choose a casting method: from the time, from a number, or by specifying the trigrams and moving line directly
- The original hexagram is built from the Earlier Heaven numbers, and the nuclear and changed hexagrams derived
- The moving line fixes subject and object; read the elemental relation across all three hexagrams