How bone weight is calculated, what counts as light or heavy, what to do without a birth hour, and why calculators disagree.
How is Chinese bone weight calculated?
First convert the Gregorian birth date to the Chinese lunar calendar. The year is read by its stem-and-branch name (for example Geng Wu, 庚午), the month and day by the lunar calendar, and the time by the 12 two-hour periods. Look up each of the four weights in its table and add them; 10 qian make 1 liang. For example, 10:30 a.m. on March 15, 1990 falls in a Geng Wu year, on day 19 of the 2nd lunar month, in the Si (巳) hour: 0.9 + 0.7 + 0.5 + 1.6 = 3.7 liang, or 3 liang 7 qian.
What are the lightest and heaviest possible bone weights?
With the standard four tables, the lightest total is 2.1 liang and the heaviest is 7.1 liang. The verses run from 2.1 to 7.2 liang, 52 in all, but 7.2 cannot be reached with these tables.
What counts as a light or heavy bone weight?
In Chinese folk usage, a total around 3 liang is often called "light" and 5 liang or more "heavy", but that is only a manner of speaking: there is no agreed standard and no statistical basis. Broadly, the verses for lighter totals describe harder lives and the heavier ones talk of wealth and status, though not every verse is better than the one before it.
Are people with a light bone weight more easily troubled by spirits?
That is a common folk belief in Taiwan, but the verses say nothing of the kind and there is no evidence for it. Your bone weight is simply four table values added together; it does not describe your constitution, your health or your luck.
Can I calculate my bone weight without knowing my birth hour?
Yes. Without a birth hour, only the year, month and day weights are fixed, so the calculator lists the total for each of the 12 two-hour periods and the range from lightest to heaviest. It never assumes a noon birth. If you roughly remember when you were born, you can focus on those few periods. A birth after 23:00 uses the next lunar day, so it gets its own line.
If I was born after 11 p.m., which day counts?
The Zi hour runs from 11 p.m. to 1 a.m. We follow the common practice of counting a birth at 11 p.m. or later as the next lunar day. If counting it as the same day would change your result, that version is shown too, so you can compare it with other calculators.
How is a birth in a leap month calculated?
The common practice, which we use, is to look up days 1–15 of a leap month under that month and days 16 onward under the following month. Another practice treats the whole leap month as the same month; when the two give different results, both are shown.
Do I need to adjust for daylight saving time?
Yes. The two-hour periods are based on standard time, so if daylight saving time was in effect when you were born, one hour is taken off before the period is looked up. The result shows the recorded time and how much was taken off.
Why do bone weight calculators give different results?
There are four common reasons: whether the year changes at Lunar New Year or at the Start of Spring (Lichun), how leap months are handled, which day a birth after 11 p.m. belongs to, and whether a site looks up the Gregorian month instead of the lunar month. A few table cells also vary between sources; the Ji Chou (己丑) year, for example, appears as either 0.7 or 0.8 liang. We use the value most tables agree on and flag the variant.
Is bone weight fortune telling accurate?
Bone weight is a folk lookup method traditionally attributed to Yuan Tiangang of the Tang dynasty, but the official histories do not record it, and the earliest dated printed version we have found is from 1946. It has no statistical or empirical support, so it is best treated as a cultural reference, not a basis for life decisions. For a closer look at career, relationships and year-by-year change, see a full Bazi chart.
How is bone weight different from a Bazi chart?
Bone weight simply adds four weights for the year, month, day and hour, and sums up a life in a single verse. A Bazi chart looks at the heavenly stems and earthly branches of the Four Pillars, the Five Elements, the Ten Gods and the Luck Pillars, so it can speak to different areas of life and different years. They are separate methods, and results for the same birthday do not need to confirm each other.
