Does It Matter Whether You Use the Solar or Lunar Calendar for Plum Blossom Numerology Divination by Numbers?

The Basic Logic of Divination by Numbers

Divination by numbers is one of the most common entry points into Plum Blossom Numerology (Meihua Yishu). Some people cast a reading from a house number, others from the last few digits of a phone number, and others simply use the date. That last approach raises an unavoidable question: which calendar?

Plum Blossom Numerology (Meihua Yishu) is traditionally attributed to Shao Yong, and its core idea is that "all things are numbers, and within numbers lies principle." Anything that can be counted — sounds, colors, directions, even a randomly spoken number — can serve as the raw material for a reading. Methods broadly fall into two types: pure-number methods and date-based methods. The calendar question only becomes real when you bring date information into the reading.

With a pure-number approach — say, someone tells you "I'm thinking of the number 35" — there is no calendar involved at all. You simply use 35 and move on. The genuine disagreement only surfaces when you bring in "what's today's date" as part of the casting.

Why the Lunar Calendar Has Always Been the Default

The classical texts of Plum Blossom Numerology (Meihua Yishu) were written entirely within a lunar-calendar frame of reference. Shao Yong lived during the Northern Song dynasty; the Gregorian calendar did not come into widespread use in China until after the founding of the Republic. The concepts discussed in those texts — "at the Winter Solstice, the first Yang line is born," the system of monthly lords (Yue Jiang) — are all built around the Chinese lunar calendar and its solar terms. From the standpoint of textual tradition, the lunar calendar is simply the native coordinate system of this art.

The most common date-based method works like this: add the year's Earthly Branch number, the month number, and the day number together to get the upper trigram; add the hour number to get the lower trigram; divide the sum of the three by six to find the moving line. The "month" and "day" figures here have always referred, in the traditional framework, to the lunar month and lunar day. Lunar month one is 1, lunar month eleven is 11 — clean and direct.

The lunar calendar also has a relatively stable relationship with the solar terms. The first lunar month usually falls around Li Chun (Start of Spring), the eleventh month around Da Xue (Major Snow), and this relationship has held fairly steady over centuries. The Gregorian calendar also corresponds to the seasons, but the dates of the solar terms shift by a day or two from year to year in the Gregorian system, making things slightly less convenient.

Is There Any Case for Using the Gregorian Calendar?

Some practitioners will ask: I live entirely by the Gregorian calendar, I have no intuitive sense of the lunar date, and converting is itself a source of errors. Can I just use the Gregorian date?

This deserves a genuine answer rather than a reflexive "the tradition says lunar, so it must be lunar."

The underlying mechanism of Plum Blossom Numerology (Meihua Yishu) is a resonance between number, mind, and the quality of the present moment. A Gregorian date is a real number that exists in your awareness right now — it is not invented or arbitrary. If your honest mental reality at the moment of casting is "today is November 18, 2024," then that number is a genuine expression of your present perception, and using it is not inherently illegitimate.

Some practitioners do in fact use Gregorian dates consistently and have developed their own coherent framework around that choice. Their argument is that Plum Blossom Numerology (Meihua Yishu) emphasizes the immediate resonance of heart, number, and principle, and that the calendar system is merely a labeling tool for time. What matters is focused sincerity at the moment of casting. This argument has some merit, but it can also easily become a rationalization for convenience — essentially "use whatever is easiest."

My own view is this: if you are using the traditional year-month-day-hour formula, stay with the lunar calendar. That formula's internal numerical structure was designed for lunar dates; substituting Gregorian figures breaks the internal logic. If you are using a pure-number or impression-based approach — a number you heard, a flash of perception — calendar system is not relevant in the first place.

The Practical Pitfalls

The most common mistake is this: the practitioner is uncomfortable converting to the lunar calendar, so they quietly use a Gregorian date while still applying the traditional year-month-day-hour formula. This is the worst of both worlds. You are feeding Gregorian numbers into a structure built for lunar numbers, and the mismatch is real.

There is also a subtler issue with the lunar calendar: intercalary months. When an intercalary month occurs — say, an intercalary eighth month — different lineages handle it differently. Some count the second eighth month as 9 and shift everything forward; others have their own conventions. There is no universal standard. When you encounter this, the most practical approach is to observe how your teacher or your reference text handles it and stay consistent. Being consistent matters more than winning the argument about which convention is correct.

Time of day, by the way, is not affected by any of this. Zi Shi (the Rat hour) begins at 11 p.m. in both the old and modern reckoning — there is no conversion ambiguity there.

One more thing worth saying: the accuracy of a Plum Blossom Numerology (Meihua Yishu) reading is not primarily determined by which calendar you used. Among experienced practitioners working with the same method, accuracy varies considerably — and the variance comes overwhelmingly from skill in reading the trigrams and hexagrams, not from the calendar choice. Treating the calendar question as the decisive factor is putting the cart before the horse.

If you are just starting out, the simplest and most defensible approach is to commit to one system and follow it throughout: either use the lunar calendar from start to finish, or find a teacher who explicitly teaches with the Gregorian calendar and adopt their full framework. Mixing the two on your own, before you have enough experience to evaluate your results, makes it nearly impossible to tell whether any error came from a calendar mismatch or from your interpretation of the reading itself.