Does Bone-Weight Divination Follow Solar Terms or Lunar Months? Decoding the Different Algorithms Results

Many friends encountering Bone-Weight Divination (Cee Gu) for the first time face a puzzling dilemma. Before deciphering the cryptic lyrics, they must decide on just one element: the month. For the same birth date, switching to a different online tool instantly changes the total bone weight and its subsequent interpretation.

The core question remains: which algorithm truly adheres to the original regulations?

First, let's separate two concepts. In BaZi (Four Pillars of Destiny), assigning months follows the Solar Terms as the boundary. Li Chun marks the start of the Yin month, Jing Zhe the Mao month, established in Zi Ping BaZi as an enduring rule. Consequently, many assumed that since Bone-Weight shares roots with BaZi, its months should logically follow the Solar Terms too.

However, turning to early vintage manuscripts reveals that the original tables listed months as the First, Second, and Twelfth Lunar Months. This contrast between the Solar logic of BaZi and the practical Lunar Month labels is where the discrepancy begins.

In essence, Bone-Weight has two distinct lineages, each with its own rationale, making it difficult to judge absolute correctness between them:

1. The Simplistic Lunar Approach The earliest circulated manuscripts favored a direct, user-friendly system using the Lunar Month. From the first day of the First Lunar Month through the thirtieth day, it was categorized as the First Month, corresponding to six money units. Similarly, the Second Lunar Month counted until the end of that month for seven money units. This method prioritized convenience; by the Ming Dynasty, commoners used it for casual reference, simply flipping open a Lunar Almanac without needing to cross-reference the precise hour of a Solar Term.

This remains the path adopted by most modern, simplified lookup charts.

2. The Refined Solar Logic Later practitioners applied the BaZi month logic to Bone-Weight. They argued that the shift in heavenly and earthly energy is defined by the Solar Term, not the Lunar New Year's Day. Even if someone was born in the First Lunar Month, if they hadn't yet passed Li Chun, their Qi still belonged to the previous year's winter, suggesting they should count for the Twelve (Winter) Month.

This approach aligns with the Four Pillars system, setting boundaries at the "Jie" (Node) points of the Twenty-Four Solar Terms.

The Conflict Zone For a specific birth date falling on the intersection of a Lunar Month and a Solar Term, the difference becomes apparent. Take a common example: in one year, Li Chun fell on the fifth day of the Lunar First Month. Born on the second day, that person was assigned to the First Month (Six Money) by the Lunar algorithm, but to the Twelve Month (Five Money) by the Solar algorithm because they hadn't yet passed the Term. A single unit of weight difference results in a significantly different total bone weight and prophecy. Those born in leap months often face even more pronounced conflicts.

But which one was the original intent of the ancient texts?

Objectively, early Lunar Bone-Weight was designed as a popular, straightforward art rather than the rigorous celestial branch system of Zi Ping BaZi. The lyrics simply listed twelve months and their weights, without a footnote specifying "Switch months by Solar Term." Dividing months by Terms was a later refinement added by scholars referencing BaZi principles.

Nevertheless, divination allows for both "Theory" (Li) and "Custom" (Su). One path prioritizes easy propagation using Lunar Months; the other emphasizes Qi flow using Solar boundaries. Both lineages have dedicated followers and no single winner.

The Year's Role A further detail complicates matters: the judgment of the Year Pillar in many versions already defaults to Li Chun, matching BaZi perfectly. Yet, only the month standard remains split between the two methods. This creates logical contradictions in many online tools—they count the year by Solar Terms but the month by Lunar New Year—mixing two different scales to produce confusing results.

How Should You Choose? For those merely dipping their toes into this traditional folk divination, the mainstream Lunar Month charts suffice. If you are deeply versed in BaZi and accustomed to observing energy shifts via Solar Terms, adopting that boundary maintains internal consistency.

The goal isn't to proclaim a winner, but to lock onto one rule set and apply it consistently from start to finish.

Many mistake Bone-Weight for an absolute fate. In reality, the bone weight serves as just one analogy in a symbolic framework built by ancients. As the measuring scales shift, so do the results.

The true artistry lies in these subtle boundaries. Outsiders see merely a few taels and money units, yet the understanding person knows these numbers represent two distinct ways of viewing time: the waxing and waning of Moon phases versus the solar cycle of cold and heat.

Next time you encounter conflicting results between websites, don't rush to judge authenticity. Simply observe which monthly rule it employs. Once you grasp the scale, your judgment will naturally come into focus.