About Mingli Paipan · Method and Classical Sources

1. Who we are

The calculation rules and readings on this site are compiled from a systematic study of the classical texts of Chinese astrology: the Complete Book of Zi Wei Dou Shu (紫微斗数全书) for the nature of the stars, the twelve palaces and the Four Transformations; the Yuan Hai Zi Ping (渊海子平) and San Ming Tong Hui (三命通会) for the Ten Gods, auxiliary stars (shensha) and Na Yin; the Zi Ping Zhen Quan (子平真诠) for chart structures and the Useful God; the Di Tian Sui (滴天髓) for strength and the flow of the Five Elements; and the Qiong Tong Bao Jian (穷通宝鉴) for seasonal climate adjustment.

The classics do not agree on every detail, and later editions contain textual variants. Our rule is simple: every calculation rule traces back to a specific classical or calendrical source, and wherever the schools differ, this page states which reading we follow and why.

The engine is publicly verifiable: the Python Zi Wei engine iztro-py is published on PyPI and the MCP server mingli-mcp is open source on GitHub. The website and the MCP server are checked against the same set of golden test vectors, so the same birth data produces an identical chart on both.

2. Classical sources

These are the main texts the site draws on, and what each one contributes.

• Complete Book of Zi Wei Dou Shu (attributed to Chen Xiyi of the Song; compiled in the Ming): the nature of the 14 major and auxiliary stars, the twelve palaces, and the Four Transformations of the birth year. Our star readings, star pairs and pattern checks follow it.
• Yuan Hai Zi Ping (Xu Ziping’s method, edited by Xu Dasheng, Song): the foundation of the Zi Ping school — the Day Master as the self and the Ten Gods as its relationships. Our Ten God names and relations follow it.
• San Ming Tong Hui (Wan Minying, Ming): the standard compendium of shensha and Na Yin; our shensha and the Na Yin of the sixty Jiazi draw on it.
• Zi Ping Zhen Quan (Shen Xiaozhan, Qing): chart structures determined by the month branch; our pattern recognition follows its principle that the Useful God is sought in the month.
• Di Tian Sui (attributed to Jing Tu; annotated by Ren Tieqiao in the Qing as Di Tian Sui Chan Wei): the “Three Origins” of stem, branch and hidden stem, and the strength and flow of the elements; we follow it when judging Day Master strength.
• Qiong Tong Bao Jian (compiled by Yu Chuntai, Qing): seasonal adjustment by Day Master and birth month, used to explain how cold, heat, dryness and damp shape a chart.

3. Calculation conventions

Casting a chart looks like a table lookup. What actually makes different calculators disagree is how they handle the edge cases below. This is how we handle them — identically on the website and the MCP server.

• Late Zi hour (23:00–24:00): the day pillar advances at 23:00 (“Zi Chu” day change). Another school changes the day at midnight and treats 23:00–24:00 as the “night Zi hour” of the same day; both have a lineage. We follow the Zi Chu convention, consistent with the traditional view that a day begins at the Zi hour.
• Each two-hour period is represented by its midpoint — the Wu hour (11:00–13:00) is computed as 12:00. This only matters on a solar-term change day, which is exactly when charts are most often wrong.
• Solar terms use the exact moment, not the calendar date: the BaZi year pillar changes at the moment of Lichun (Start of Spring) and the month pillar at the moment of each of the twelve “Jie” terms. The site ships a minute-precision table of term moments for 1900–2100.
• The Zi Wei birth-year stem changes at Lunar New Year, while the BaZi year pillar changes at Lichun. Someone born between the two will see different year stems in the two charts — each discipline follows its own rule; it is not an error. In 2027, for example, Lichun falls on February 4 at 09:46 (UTC+8) and Lunar New Year on February 6.
• True solar time: the traditional hours were read from a sundial, so they are local solar time. The site can correct for the longitude of the birthplace and the equation of time. Lhasa (about 91.1°E) keeps Beijing time, so a clock time of 12:00 there is around 10:00 in true solar time, give or take a quarter of an hour by season — the Si hour rather than the Wu hour.
• Birth time zone: a solar term is a single astronomical instant, and the site's term table is in Beijing time (UTC+8). For births elsewhere, the birth moment is converted to Beijing time before checking whether the term has passed, which decides the year and month pillars; the day and hour pillars still follow local time at the birthplace. Without a birthplace, the time you enter is read as Beijing time, so if you were born outside UTC+8, switch on birthplace correction under Advanced options and choose your birth city.

4. Why different calculators give different charts

When two charts disagree, checking these points usually reveals the cause.

• Different late-Zi-hour conventions (day change at 23:00 vs. midnight).
• Solar terms by date vs. by exact moment — people born on a term-change day often get a month pillar that is off by one.
• Whether true solar time is applied, and which longitude is used.
• Zi Wei schools differ on a few star placements and transformations, for example the Science and Taboo transformations of certain year stems.
• Mixing up Lunar New Year and Lichun — using the lunar year for the BaZi year pillar, or Lichun for the Zi Wei year stem.

Independent measurement: Jade Almanac ran 13 boundary moments through eight BaZi calculators and documented which convention each applies for the Lichun year boundary, the 23:00 day change, true solar time and daylight saving, with the data released under CC0. We checked all 13 moments: this site's default output matches the implementations that likewise change the day at 23:00 and the year at Lichun. BaZi Calculator Convention Audit

5. What AI does and does not do here

• Charts are computed entirely by deterministic code. AI performs no calculation; the same birth data always yields the same chart.
• Free rule-based readings come from a hand-written rule library: the code selects entries for your chart, and the text was written in advance — it is not AI-generated.
• Paid AI readings and consultations have the AI read the already-computed chart data. Answers cite the palaces, stars and stems they rely on, so you can check each point against your own chart.
• Readings are offered for cultural interest and self-reflection. They are not medical, legal, financial or psychological advice, and the AI is instructed not to make fatalistic predictions.

6. Corrections and contact

If you find an error in a rule, quotation or reading, write to [email protected] with the birth data (date and hour are enough) and the source you believe is correct. Once verified, we fix it and update the date on this page.

Frequently asked questions

If I was born between 11 pm and midnight, which day is my day pillar?

This site uses the Zi Chu convention: the day pillar advances to the next day at 23:00. Another school changes the day at midnight and calls 23:00–24:00 the “night Zi hour” of the same day. If another calculator gives you a day pillar one day off from ours, this is the most likely reason.

Why do different BaZi calculators give different results?

The four usual causes are: different late-Zi-hour conventions; changing the month by calendar date instead of the exact solar-term moment; whether true solar time is applied; and using Lunar New Year instead of Lichun for the year pillar. Checking these four points usually explains the difference.

Do I need true solar time? Does the site use my current location?

True solar time is off by default: the chart uses the clock time you enter, and the site does not read your location. To apply it, open Advanced options, switch on true solar time and enter your birthplace. The “Auto-detect” button there uses where you are now, so it only helps if you are near your birthplace. If you were born outside UTC+8, switch it on and choose your birth city: the year and month pillars depend on your birth time zone.

I was born around Chinese New Year. Which date decides my year pillar and zodiac?

The BaZi year pillar changes at the exact moment of Lichun (Start of Spring, around February 4); the Zi Wei birth year changes at Lunar New Year. If you were born between the two, the year stems in the two charts differ — each system follows its own rule, and neither is an error.